Three dimensionally synthetizing a digital audio signal

Abstract

Methods are provided of three dimensionally synthetizing a digital audio signal depending on spatial commands and filter instructions. Such methods comprise: performing, depending on the spatial commands, a spatialization method at audio rate on the digital audio signal to spatialize it and therefore produce a spatialized audio signal whose reproduction implements, in a three dimensional, 3D, audible space, spatialized virtual sound sources defined by spatial parameters; performing, depending on the filter instructions, digital filtering on the spatialized audio signal to produce an evolved or synthetised audio signal whose reproduction implements, in the 3D audible space, evolved virtual sound sources; and providing the evolved audio signal to a plurality of loudspeakers or headphones to reproduce the evolved audio signal and, therefore, implement the evolved virtual sound sources in the 3D audible space. Systems, computer systems and computer programs that are suitable for performing such methods are also provided.

Description

[0001] The present disclosure relates to methods of three dimensionally synthetizing a digital audio signal, and to systems, computer programs and computing systems suitable for performing said methods.BACKGROUND

[0002] Digital sound / audio synthetisers are known which digitally synthetise input digital audio signal(s) to generate output synthetised digital audio signal(s) whose reproduction results in corresponding sounds or sound effects within audible space. These current synthetisers show limitations or limited aspects whose enhancement may be desirable to implement applications thereof in more optimal or effective manner, or even new applications unknown or non-implementable so far.

[0003] One of these limitations is that current synthetisers yield synthetised audio signals whose reproduction shows low or limited immersivity effect on listeners within audible space. In other words, sound resulting from such a reproduction is received by listeners with rather moderate immersion perception and, therefore, enhancement of said effect may be interesting for applications thereof. Current synthetisers also do not output synthetised audio signals that are (fully) directly reproducible by multidimensional reproduction systems to generate multidimensional sound in multidimensional space. Another limitation is that current synthetisers do not provide users thereof with an instant or near instant interactivity with ongoing sound that is being reproduced within multidimensional space. This (near) instant interactivity between user ruling and running sound may be very interesting in user driven applications in which (near) instant implementation or influence of user instructing into ongoing sound may be very useful. That is, minimum or near-zero delay between user instructing and its reflection into ongoing sound may be especially valuable in certain applications.

[0004] Current synthetisers also offer reduced or limited performance in generation of new (innovative, even unpredictable) sounds over spectral sound-domain combined with spatial sound-domain. Present synthetisers are rather ineffective to synergically combine spectral and multi-spatial sound-domains to generate sounds "never heard before". Improving such a limitation regarding multi-sound-dimensionality in present synthetisers may be an interesting challenge to be faced. Furthermore, already known synthetisers provide reduced or limited range of user-rulable parameters (via, e.g., keys, knobs, sliders or combinations thereof in existing synthetisers), and said limited range necessarily restricts user's capacity of generating sounds and / or influencing ongoing sounds in multidimensional audible space.

[0005] An object of this disclosure is to provide new methods, systems and computer programs aimed at improving prior art manners of three dimensionally synthetizing a digital audio signal.SUMMARY

[0006] In an aspect, methods are provided of three dimensionally synthetizing a digital audio signal depending on spatial commands and filter instructions.

[0007] These methods (also denominated synthetizing methods herein) comprise performing, depending on (or as commanded by) the spatial commands, a spatialization method at audio rate on the digital audio signal to spatialize it and therefore produce a spatialized audio signal whose reproduction implements, in a 3D audible space, spatialized virtual sound sources defined by or including spatial parameters (also herein denominated spatial-params).

[0008] Synthetizing methods further comprise performing, depending on (or as instructed by) the filter instructions, digital filtering on the spatialized audio signal to produce an evolved audio signal whose reproduction implements, in the 3D audible space, evolved virtual sound sources.

[0009] Synthetizing methods still further comprise providing the evolved audio signal to a plurality of loudspeakers or headphones to reproduce the evolved audio signal and, therefore, implement the evolved virtual sound sources in the 3D audible space.

[0010] Audio rate is defined herein as the speed at which (user) control commands (i.e., spatial commands and filter instructions) are processed. More specifically, audio rate relates to the speed at which the audio is sampled digitally or, in other words, the speed at which a new-next digital audio sample is available in the digital audio signal which, in the technical context described herein, is the input signal to be three-dimensionally synthetised by synthetising methods according to present disclosure. This means that new (user) control command(s), or control value(s), is / are processed with every audio sample, i.e. at the same rate as the audio is sampled.

[0011] Such synthetizing methods thus receive one or more (input) digital audio signals and process them to produce one or more (output) evolved or synthetised digital audio signals whose reproduction overcomes at least some of the aforementioned drawbacks related to immersivity effect, direct multidimensional reproduction, user-sound interactivity, synergic spectral and multi-spatial combination, range of user-rulable parameters. Taking this into account, the providing of the evolved or synthetised audio signal(s) to loudspeakers or headphones may be optional, since nuclear aspect of synthetizing methods provided herein is how the one or more (input) digital audio signals are processed to yield the one or more evolved (or synthetised) audio signals whose reproduction implies at least some of the cited 3D-sound-related enhancements.

[0012] Regarding immersivity effect, synthetising methods according to present disclosure provide synthetised audio signal(s) whose reproduction may cause enhanced immersivity effect. This enhancement may be conceptually understood via the fact that such synthetising methods synthetise audio signal(s) with spatialization function at its operational core integrated with digital filtering. Indeed, spatialization at audio rate and digital filtering synergistically cooperate to improve immersivity effect.

[0013] In relation to user-sound interactivity and direct multidimensional reproduction, said aspects may also be enhanced by synthetising methods according to present disclosure. This upgrade may be conceptually understood through the fact that the aforementioned synergistic integration of spatialization at audio rate and digital filtering may imply reduction or even avoidance of processing layers or connections or interfaces in comparison to known assemblies that are mounted or mountable to synthetise sound / audio in 3D audible space

[0014] With respect to two-fold synthetising of sound based on "intimal" combination of spectral and multi-spatial sound-domains, this may be conceptually explained by the fact that the aforementioned combination of spatialization at audio rate and digital filtering in integral or monolithic manner permits influencing ongoing sound (i.e., sound that is being reproduced) from both spectral and multi-spatial perspectives in interlaced manner.

[0015] In reference to range of user-rulable parameters, said aspect may also be enhanced by synthetising methods according to present disclosure since (user-driven) spatial commands influencing spatialization and (user-driven) filter instructions influencing digital filtering may provide the user with a very broad range of user-rulable parameters and combinations thereof.

[0016] In implementations, the spatialization method may be or may include or may be based on Vector Base Amplitude Panning, VBAP, method, or an Ambisonics method, or a Wavefield Synthesis, WFS, method, or a binaural method, or any other known spatialization method for spatializing a digital audio signal in a 3D audible space.

[0017] The performing of the spatialization method may comprise modulating, depending on (or as commanded by) the spatial commands, the spatial-params defining the spatialized virtual sound sources at audio rate. Said modulating may be performed by or may include applying modulating functions to the spatial-params. These spatial-params may comprise one or more of among rotation speed, rotation acceleration, rotation axis orientation, rotation radius, spread or dimensional amplitude of the spatialized virtual sound sources. Such a modulating may cause sound effects such as, e.g., varying frequency split along rotation axes on a one per one basis.

[0018] The applying of modulating functions may comprise applying, depending on (or as commanded by) first spatial commands included in the spatial commands, High Frequency Oscillations (HFOs) on at least some of the spatial-params. Said HFOs may be performed in continuous and uniform manner at audio rate over time with an oscillation or variation rate above (or equal to) 20 Hz. Such a performing of HFOs may cause generation of sound effects such as, e.g., harmonic or non-harmonic spectrum generation or any combination thereof. HFOs ruled / commanded by user (in or through first spatial commands) are just one of the many options the user may have to interact with and, therefore, influence the running sound. Hence, first (or HFO) commands may contribute to provide user with broad range of user-rulable parameters to influence ongoing sound, thereby improving and promoting immersivity effect and synergies in combination of spectral and multi-spatial sound-domains.

[0019] The applying of modulating functions may comprise applying, depending on (or as commanded by) second spatial commands included in the spatial commands, Low Frequency Oscillations (LFOs) on one or more of the spatial-params. Said LFOs may be performed in continuous and uniform manner at audio rate over time with an oscillation or variation rate below (or equal to) 20 Hz. This performing of LFOs may generate sound effects such as, e.g., phase or vibrato or tremolo or frequency shifting or any combination thereof. LFOs ruled / commanded by user (in or through second spatial commands) are just one of the many possibilities the user may have to interact with and, hence, influence the ongoing sound. Then, second (or LFO) commands may help to provide user with very broad set of user-rulable parameters to affect ongoing sound, and this may support improvement and / or promotion of immersivity effect and / or synergetic combination of spectral and multi-spatial sound-domains.

[0020] The applying of modulating functions may comprise applying, depending on (or as commanded by) third spatial commands included in the spatial commands, combination or combinations of oscillations (HFOs and / or LFOs) at audio rate on all or part of the spatial-params. Oscillations (HFOs and / or LFOs) may be combined according to parallel or in-series approach. Parallel approach means that HFOs / LFOs are applied simultaneously (i.e., in parallel). In-series approach means that oscillations (HFOs / LFOs) are applied one after another and, therefore, one oscillation influences / modulates another previously applied oscillation. For example, first HFO / LFO may be applied to a spatial-param, so that the spatial-param starts to oscillate according to said first HFO / LFO; then, second HFO / LFO may be applied to the first HFO / LFO, so that said first HFO / LFO results influenced / modulated by the second HFO / LFO, and so on (e.g., until an n-th HFO / LFO). This performing of combined or mixed oscillations (HFOs / LFOs) may result in complex modulation of the spatial-params affected (by third spatial commands), thereby causing generation of sound effects including, e.g., complex spectra generation. Similar benefits and effects as those explained regarding HFOs (and related first spatial commands) and LFOs (and related second spatial commands) may be attributed or attributable to combination of HFOs and / or LFOs. Indeed, said combinations of oscillations may also contribute to improve limitations of present synthetisers: immersivity effect, user-sound interactivity, synergic spectral and multi-spatial combination, range of user-rulable parameters.

[0021] The applying of modulating functions may comprise applying, depending on (or as commanded by) fourth spatial commands included in the spatial commands, one or more envelopes on at least part of the spatial-params. This enveloping may cause the spatial-params affected (by fourth spatial commands) to change at audio rate over time following a waveform including one or more of among attack phase, hold phase, decay phase, delay phase, sustain phase and release phase. Similar benefits and effects as those explained regarding HFOs (and related first spatial commands), LFOs (and related second spatial commands) and combinations of oscillations (and related third spatial commands) may be attributed or attributable to envelopes (and related fourth spatial commands ruling them). Since envelopes have a temporal beginning and end, which may be defined / triggered by user through fourth spatial commands, user-sound interactivity is further enhanced. In a keyboard-based synthetiser, such beginning and end may be ordered / commanded by user via key pressing and releasing, respectively, in such a manner that said pressing may trigger fourth spatial command indicating beginning and said releasing may trigger fourth spatial command indicating end.

[0022] The above modulations or application of modulating functions based on LFO(s), HFO(s), mixed oscillation(s) and envelope(s) or combination(s) thereof may be performed on corresponding spatial-params per rotation axis or per spatial dimension or both in the 3D audible space. Improvable aspects of current synthetisers (immersivity effect, user-sound interactivity, synergic spectral and multi-spatial combination, range of user-rulable parameters) may be further enhanced with said feature or combination of features.

[0023] The performing of the digital filtering on the spatialized audio signal may comprise applying, depending on (or as instructed by) the filter instructions, one or more digital filters to the spatialized virtual sound sources or, in particular, to spatial region that each of the spatialized virtual sound sources occupies over time. Such digital filters may include one or more of among: High-pass Filter, Low-pass Filter, Band-pass Filter, Band-stop Filter, Notch Filter, All-pass Filter, Equalization Filter, Comb Filter, Amplifier, Compressor, Limiter, Distortion, Delay, Echo, Chorus, Flanger, Reverberation, Blurring, Widening, Sharpening, Mirroring, Rotation, Windowing, Warping. This broad digital filtering (broad in the sense that filtering is implementable in many different manners) may open / extend even more the range of user-rulable parameters through which user may intervene on running sound with zero or near zero delay between user ruling and its reflection on reproducing sound. Such a broadly customizable filtering of spatially distributed or spread sound may also contribute to enhance immersivity effect, as well as the other aspects of present synthetisers that are enhanced by synthetising methods according to present disclosure.

[0024] Each of said digital filters includes filter parameters (also herein denominated filter-params). Said filter-params may include, e.g., Centre Frequency, Gain and Q (Quality), which are filter-params of High-pass Filter or Low-Pass Filter or Band-pass Filter or Band-stop Filter or Notch Filter. In general, aforementioned digital filters may be operated depending on filter-params that are known to influence or characterize their behaviour. Since the filter-params that each of the cited digital filters may have associated are known in the technical field at hand, no more details thereon are provided herein.

[0025] The performing of the digital filtering on the spatialized audio signal may comprise generating or creating, depending on (or as instructed by) first filter instructions included in the filter instructions, spatialized parameters (also herein denominated spatialized-params) or instances thereof. Each of said spatialized-params or instances thereof may include or refer to one of the filter-params (of one of the digital filters to be applied) and one or more associated meta-parameters (also herein denominated filter-meta-params) defining a region of / in the 3D audible space in which its associated filter-param has or will have or can have effect. Different instances of same filter-param may thus have an independent or distinct effect on disjoint or fully or partially overlapping regions in the 3D audible space. Such spatialized-params, mainly their respective filter-meta-params, may especially extend the many manners in which user may influence on running sound. With the spatialized-params, filter-params may be altered not only regarding their values but also spatially, i.e., filter-params' values may be tuned and, additionally, said tuning's effect may be restricted to particular region(s) in the audible 3D space. Limitations of current synthetisers regarding, e.g., immersivity effect, user-sound interactivity, synergic spectral and multi-spatial combination and range of user-rulable parameters may thus be enhanced at least in part due to the proposed spatialized-params and their use. For example, the fact that user can impact not only on filter-params' values but also on particular effect regions within 3D audible space, increases the granularity under / with which user can influence ongoing sound. This increased granularity under / with which user can drive / rule the synthetising of sound may also contribute to improve immersion effect, user-sound interactivity, etc.

[0026] The performing of the digital filtering may comprise setting, depending on (or as instructed by) one or more of the first filter instructions, the filter-meta-params (in spatialized-params) with data defining its associated filter-param's effect region in the 3D audible space. Said filter-meta-params or, in other words, its related effect region data may include or denote or refer to one or more of among: spatial coordinates in the 3D audible space defining said effect region, 2D or 3D angle within rotation circular or spherical bound(s) to which said effect region is restricted, transition rate of the filter-param associated to the filter-meta-param either within said effect region or between different effect regions in the 3D audible space. This setting of filter-meta-params may contribute to improve limitations of prior art synthetisers for same or similar reasons as the ones commented with respect to spatialized-params creation.

[0027] The performing of the digital filtering may comprise applying, depending on (or as instructed by) second filter instructions included in the filter instructions, one or more envelopes on at least some of the filter-params in the spatialized-params. Each of said envelopes may be a localized envelope or a non-localized envelope. A localized envelope may be an envelope with one or more meta-parameters (also herein denominated envelope-meta-params) defining a region of / in the 3D audible space in which said localized envelope has or will have or can have effect. A non-localized envelope may be an envelope not restricted spatially, i.e., without envelope-meta-param(s).

[0028] A localized envelope may be applied to a filter-param to cause its value to vary or, in other words, to be influenced by or according to said localized envelope in spatially restricted manner. If the filter-param is not a spatially restricted filter-param (i.e., with no associated filter-meta-param), then said spatial restriction only depends on the effect region defined by the envelope-meta-param of the localized envelope applied to the filter-param. Otherwise, if the filter-param is a spatially restricted filter-param (i.e., with associated filter-meta-param), then said spatial restriction depends on combination of the effect region defined by the envelope-meta-param and the effect region defined by the filter-meta-param. This combination of both effect regions may be their intersection in the 3D audible space.

[0029] A non-localized envelope may be applied to any of a filter-param's value, a filter-meta-param, an envelope-meta-param, an LFO-meta-param (defined in other parts of the disclosure). Application of non-localized envelope to filter-param implies that the filter-param's value is varied or influenced by said non-localized envelope. Application of non-localized envelope to filter-meta-param implies that the filter-meta-param's effect region is varied or influenced by said non-localized envelope. Application of non-localized envelope to envelope-meta-param implies that the envelope-meta-param's effect region is varied or influenced by said non-localized envelope. Application of non-localized envelope to LFO-meta-param implies that the LFO-meta-param's effect region is varied or influenced by said non-localized envelope.

[0030] With such advanced envelopes (i.e., localized and non-localized envelopes) user's leeway to actuate on in-progress sound may be widened even more. Hence, range of user-ruling parameters is extended and other aspects such as, e.g., immersivity effect, user-sound interactivity, synergic spectral and multi-spatial combination are also accordingly enhanced.

[0031] The performing of the digital filtering may comprise applying, depending on (or as instructed by) third filter instructions included in the filter instructions, one or more Low Frequency Oscillations (LFOs) on at least part of the filter-params in the spatialized-params. Each of said LFOs may be a localized LFO or a non-localized LFO. A localized LFO may be an LFO with one or more meta-parameters (also herein denominated LFO-meta-params) defining a region of / in the 3D audible space in which said localized LFO has or will have or can have effect. A non-localized LFO may be an LFO not restricted spatially, i.e., without LFO-meta-param(s).

[0032] A localized LFO may be applied to a filter-param to cause its value to vary or, in other words, to be influenced by or according to said localized LFO in spatially restricted manner. If the filter-param is not a spatially restricted filter-param (i.e., with no associated filter-meta-param), then said spatial restriction only depends on the effect region defined by the LFO-meta-param of the localized LFO applied to the filter-param. Otherwise, if the filter-param is a spatially restricted filter-param (i.e., with associated filter-meta-param), then said spatial restriction depends on combination of the effect region defined by the LFO-meta-param and the effect region defined by the filter-meta-param. This combination of both effect regions may be their intersection in the 3D audible space.

[0033] A non-localized LFO may be applied to any of a filter-param's value, a filter-meta-param, an envelope-meta-param, an LFO-meta-param. Application of non-localized LFO to filter-param implies that the filter-param's value is varied or influenced by said non-localized LFO. Application of non-localized LFO to filter-meta-param implies that the filter-meta-param's effect region is varied or influenced by said non-localized LFO. Application of non-localized LFO to envelope-meta-param implies that the envelope-meta-param's effect region is varied or influenced by said non-localized LFO. Application of non-localized LFO to LFO-meta-param implies that the LFO-meta-param's effect region is varied or influenced by said non-localized LFO.

[0034] With such advanced LFOs (i.e., localized and non-localized LFOs) user's capacity to influence on in-progress sound may be even further extended for similar reasons as the ones provided in relation to localized and non-localized envelopes.

[0035] In a further aspect, systems are provided for three dimensionally synthetizing a digital audio signal depending on spatial commands and filter instructions. Such systems (also denominated synthetizing systems herein) comprise a spatializer module, a filterer module and a reproducer module. The spatializer module is configured to perform, depending on (or as commanded by) the spatial commands, a spatialization method at audio rate on the digital audio signal to spatialize it and therefore produce a spatialized audio signal whose reproduction implements, in a three dimensional, 3D, audible space, spatialized virtual sound sources defined by or including spatial-params. The filterer module is configured to perform, depending on (or as instructed by) the filter instructions, digital filtering on the spatialized audio signal to produce an evolved audio signal whose reproduction implements, in the 3D audible space, evolved virtual sound sources. The reproducer module is (or may be) configured to provide the evolved audio signal to a plurality of loudspeakers or headphones to reproduce the evolved audio signal and, therefore, implement the evolved virtual sound sources in the 3D audible space.

[0036] Synthetizing systems are suitable or configured to perform synthetizing methods proposed herein, so same or similar functional principles and advantages as the ones described with reference to synthetizing methods may be attributed to such synthetizing systems.

[0037] In a still further aspect, computer programs are provided comprising program instructions for causing a system or computer system to perform synthetizing methods of three dimensionally synthetizing a digital audio signal, such as those described in other parts of the disclosure. These computer programs (also denominated synthetizing computer programs herein) may be embodied on a storage medium and / or carried on a carrier signal. Since synthetizing computer programs are suitable or configured to perform synthetizing methods proposed herein, same or similar functional fundamentals and advantages as the ones described with reference to synthetizing methods may be attributed to such synthetizing computer programs.

[0038] In a yet further aspect, computing systems are provided for three dimensionally synthetizing a digital audio signal, said computing systems comprising a memory and a processor, embodying instructions stored in the memory and executable by the processor, and the instructions comprising functionality or functionalities to execute methods of three dimensionally synthetizing a digital audio signal such as those described in other parts of the disclosure. Such computing systems (also denominated synthetizing computing systems herein) are suitable or configured to perform synthetizing methods described herein, so same or similar functional principles and advantages as the ones described with reference to synthetizing methods may be attributed to such synthetizing computing systems.BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Non-limiting examples of the disclosure will be described in the following, with reference to the appended drawings, in which: Figure 1 is a block diagram schematically illustrating synthetizing systems for three dimensionally synthetizing a digital audio signal, according to examples. Figure 2 is a flow chart schematically illustrating synthetizing methods of three dimensionally synthetizing a digital audio signal, according to examples. DETAILED DESCRIPTION OF EXAMPLES

[0040] Figure 1 is a block diagram schematically illustrating synthetizing systems or synthetisers 100 for three dimensionally (3D) synthetizing a digital audio signal, according to examples. Synthetizing systems 100 may be configured to receive the digital audio signal 112 from, e.g., digital audio signal source 111, and to perform the 3D synthetizing depending on spatial commands 109 and filter instructions 110 from, e.g., user device 108. Synthetizing systems 100 may include a spatializer module 101, a (multidimensional) filterer module 102 and a reproducer module 103.

[0041] Spatializer module 101 may be configured to perform, depending on or as commanded by the spatial commands 109, a spatialization method at audio rate on the digital audio signal 112 to spatialize it and therefore produce a spatialized audio signal 104 whose reproduction implements, in a three dimensional (3D) audible space, spatialized virtual sound sources defined by or including spatial-params. The spatialization method may be (or may include or may be based on) Vector Base Amplitude Panning, VBAP, method, or an Ambisonics method, or a Wavefield Synthesis, WFS, method, or a binaural method, or any other known spatialization method suitable for spatializing a digital audio signal in a 3D audible space.

[0042] In examples, the performing of the spatialization method may comprise modulating, depending on the spatial commands 109, the spatial-params defining the spatialized virtual sound sources. Such a modulating may be performed at audio rate to keep coherence with whole synthetising process. The spatial-params may comprise rotation speed, or rotation acceleration, or rotation axis orientation, or rotation radius, or spread or dimensional amplitude of the spatialized virtual sound sources.

[0043] The modulating of the spatial-params may comprise applying, depending on spatial commands 109, different types of modulations or applications of modulating functions such as, e.g., How Frequency Oscillations (HFOs), Low Frequency Oscillations (LFOs), combinations of HFOs and / or LFOs, envelopes, etc., or any combination thereof on spatial-params. Such modulating functions including HFOs, LFOs, HFO-LFO combinations, envelopes, etc. are properly described functionally and technically in other parts of the disclosure, so no more details thereon are provided here for reasons of redundancy avoidance. HFOs may be user-commanded via first spatial commands indicating said modulating function and parameters thereof defining how and / or according to which conditions said modulating function is to be performed. LFOs may be user-commanded via second spatial commands indicating said modulating function and parameters thereof defining how and / or according to which conditions said modulating function is to be performed. Combinations of HFOs and LFOs may be user-commanded via third spatial commands indicating said modulating function and parameters thereof defining how and / or according to which conditions said modulating function is to be performed. Envelopes may be user-commanded via fourth spatial commands indicating said modulating function and parameters thereof defining how and / or according to which conditions said modulating function is to be performed.

[0044] First, second, third and fourth spatial commands instructing the spatializer module 101 to perform such modulations or modulating functions may include single-modulation commands and multi-modulation commands. Single-modulation command may correspond to spatial command instructing (the spatializer module 101) to perform only one of the cited modulations or modulating functions. Multi-modulation command may correspond to spatial command instructing (the spatializer module 101) to perform several of the cited modulations at same time, or delayed from each other, or weighted combined, etc.

[0045] First, second, third and fourth multi-modulation spatial commands may not be disjoint multi-modulation spatial commands, since same type of modulation (i.e., HFO, LFO, HFO-LFO combination, envelope) may be commanded by any of said first, second, third and fourth multi-modulation spatial commands in combination with other types of modulating functions. Flexibility of these proposed multi-modulation spatial commands is clear, which may permit generating synthetized sounds never experienced before.

[0046] Multidimensional filterer module 102 may be configured to perform, depending on or as instructed by the filter instructions 110, digital filtering of the spatialized audio signal 104 to produce an evolved or synthetised audio signal 105 whose reproduction implements, in the 3D audible space, evolved virtual sound sources. Such a performing of the digital filtering may include applying, depending on the filter instructions, one or more digital filters to the spatialized virtual sound sources or, in particular, to spatial region that each of the spatialized virtual sound sources occupies over time. Each of said digital filters includes filter-params through which behaviour or operation of the digital filter may be ruled.

[0047] Digital filters that are applicable to the spatialized audio signal 104 and, therefore, to the spatialized virtual sound sources one or more of among: High-pass Filter, Low-pass Filter, Band-pass Filter, Band-stop Filter, Notch Filter, All-pass Filter, Equalization Filter, Comb Filter, Amplifier, Compressor, Limiter, Distortion, Delay, Echo, Chorus, Flanger, Reverberation, Blurring, Widening, Sharpening, Mirroring, Rotation, Windowing, Warping. Filter-params through which behaviour or operation of each of said digital filters may be ruled are already known, so no further details thereon are provided.

[0048] The performing of the digital filtering may comprise performing, depending on or as instructed by filter instructions 110, different types of filter-related functions. Examples of filter-related functions are: creation of spatialized-params or instances thereof; setting of filter-meta-params of / in spatialized-params; spatially restricted enveloping (localized enveloping) of filter-param values of / in spatialized-params; spatially non-restricted enveloping (non-localized enveloping) of filter-param values, filter-meta-params, envelope-meta-params, LFO-meta-params, etc.; spatially restricted LFO application (localized LFOs) to filter-param values of / in spatialized-params; spatially non-restricted LFO application (non-localized LFOs) to filter-param values, filter-meta-params, envelope-meta-params, LFO-meta-params, etc. Since said filter-related functions are properly described functionally and technically in other parts of the disclosure, no more details thereon are provided here for reasons of redundancy avoidance.

[0049] Filter-related functions of creating spatialized-params and of setting filter-meta-params may be user-instructed via first filter instructions indicating the filter-related function to be performed and parameters thereof defining how and / or according to which conditions the indicated filter-related function is to be performed. Filter-related functions of localized enveloping and of non-localized enveloping may be user-instructed via second filter instructions indicating the filter-related function to be performed and parameters thereof defining how and / or according to which conditions the indicated filter-related function is to be performed. Filter-related functions of localized LFO application and of non-localized LFO application may be user-instructed via third filter instructions indicating the filter-related function to be performed and parameters thereof defining how and / or according to which conditions the indicated filter-related function is to be performed.

[0050] First, second and third filter instructions commanding the (multidimensional) filterer module 102 to perform such filter-related functions may include single-function instructions and multi-function instructions. Single-function instruction may correspond to filter instruction commanding (the filterer module 102) to perform only one of the cited filter-related functions. Multi-function instruction may correspond to filter instruction commanding (the multidimensional filterer module 102) to perform several of the cited filter-related functions at same time, or delayed from each other, or weighted combined, etc.

[0051] First, second and third multi-function filter instructions may not be disjoint multi-function filter instructions, since same type of filter-related function (i.e., creation of spatialized-params, setting of filter-meta-params, localized enveloping non-localized enveloping, localized LFO application, non-localized LFO application) may be instructed by any of said first, second and third multi-function filter instructions in combination with other types of filter-related functions. Flexibility of these proposed multi-function filter instructions is clear, which may permit generating synthetized sounds never undergone before.

[0052] Reproducer module 103 may be configured to provide the evolved or synthetised audio signal 105 to a plurality of loudspeakers (or headphones) 107 to reproduce the evolved audio signal 106 and, therefore, implement the evolved virtual sound sources in the 3D audible space. If some kind of encoding has been performed in the spatialization of the digital audio signal and / or in the digital filtering of the spatialized audio signal, reproducer module 103 may include a decoder to decode the encoded filtered spatialized audio signal, so that it is reproducible by loudspeakers (or headphones) 107.

[0053] As used herein, the term "module" may be understood to refer to software, firmware, hardware and / or various combinations thereof. It is noted that the modules are exemplary. The modules may be combined, integrated, separated, and / or duplicated to support various applications. Also, a function described herein as being performed by a particular module may be performed by one or more other modules and / or by one or more other devices instead of or in addition to the function performed by the described particular module.

[0054] The modules may be implemented across multiple devices, associated or linked to corresponding synthetizing systems proposed herein, and / or to other components that may be local or remote to one another. Additionally, the modules may be moved from one device and added to another device, and / or may be included in both devices, associated to corresponding synthetizing systems proposed herein. Any software implementations may be tangibly embodied in one or more storage media, such as, e.g., a memory device, a floppy disk, a compact disk (CD), a digital versatile disk (DVD), or other devices that may store computer code.

[0055] Synthetizing systems according to present disclosure may be implemented by computing means, electronic means or a combination thereof. The computing means may be a set of instructions (e.g., a computer program) and then synthetizing systems may comprise a memory and a processor, embodying said set of instructions stored in the memory and executable by the processor. These instructions may comprise functionality or functionalities to execute corresponding synthetizing methods such as those described in other parts of the disclosure.

[0056] In synthetizing systems implemented only by electronic means, a controller of the system may be, for example, a CPLD (Complex Programmable Logic Device), an FPGA (Field Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit).

[0057] In synthetizing systems that are a combination of electronic and computing means, the computing means may be a set of instructions (e.g., a computer program) and the electronic means may be any electronic circuit capable of implementing corresponding steps of synthetizing methods proposed herein, such as those described in other parts of the disclosure.

[0058] The computer programs may be embodied in / on a storage medium (for example, a CD-ROM, a DVD, a USB drive, a computer memory or a read-only memory) or carried on a carrier signal (for example, on an electrical or optical carrier signal).

[0059] The computer programs may be in the form of source code, object code, a code intermediate source and object code such as in partially compiled form, or in any other form suitable for use in implementing synthetizing methods according to present disclosure. The carrier may be any entity or device capable of carrying the computer programs.

[0060] For example, the carrier may comprise a storage medium, such as a ROM, for example a CD ROM or a semiconductor ROM, or a magnetic recording medium, for example a hard disk. Further, the carrier may be a transmissible carrier such as an electrical or optical signal, which may be conveyed via electrical or optical cable or by radio or other means.

[0061] When the computer programs is / are embodied in a signal that may be conveyed directly by a cable or other device or means, the carrier may be constituted by such cable or other device or means. Alternatively, the carrier may be an integrated circuit in which the computer programs is / are embedded, the integrated circuit being adapted for performing, or for use in the performance of, synthetizing methods proposed herein.

[0062] Figure 2 is a flow chart schematically illustrating synthetizing methods of three dimensionally synthetizing a digital audio signal depending on spatial commands and filter instructions, according to examples. Since synthetizing methods according to Figure 2 are performable by or at synthetizing systems according to Figure 1, number references from said Figure 1 may be reused in following description of Figure 2.

[0063] Synthetizing methods may be initiated (e.g., at block 200) upon detection of a starting condition such as, e.g., a user request to start the synthetizing method.

[0064] Synthetizing methods may further include (e.g., at method-block 201) performing, depending on the spatial commands, a spatialization method at audio rate on the digital audio signal to spatialize it and therefore produce a spatialized audio signal whose reproduction implements, in a 3D audible space, spatialized virtual sound sources defined by or including spatial-params. This spatializing functionality implemented or implementable at method-block 201 may be performed by, e.g., spatializer module 101 as previously described with reference to Figure 1. Functional details and considerations explained about spatializer module 101 may thus be similarly attributed or attributable to method-block 201.

[0065] Synthetizing methods may still further include (e.g., at method-block 202) performing, depending on the filter instructions, multidimensional digital filtering on the spatialized audio signal to produce an evolved audio signal whose reproduction implements, in the 3D audible space, evolved virtual sound sources. This filtering functionality implemented or implementable at method-block 202 may be performed by, e.g., multidimensional filterer module 102 previously described with reference to Figure 1. Functional details and considerations explained about multidimensional filterer module 102 may thus be similarly attributed or attributable to method-block 202.

[0066] Synthetizing methods may yet further include (e.g., at method-block 203) providing the evolved audio signal to a plurality of loudspeakers or headphones to reproduce the evolved audio signal and, therefore, implement the evolved virtual sound sources in the 3D audible space. This reproducing functionality implemented or implementable at method-block 203 may be performed by, e.g., reproducer module 103 previously described with reference to Figure 1. Functional details and considerations explained about reproducer module 103 may thus be similarly attributed or attributable to method-block 203.

[0067] Synthetizing methods may additionally include (e.g., at decision block 204) verifying whether an ending condition occurs or is satisfied. In case of positive or true result Y of said verification, synthetizing method may proceed to method-block 205 to terminate execution of the method. Otherwise N, synthetizing method may loop back to previous method-block 201 to perform a new iteration to, e.g., synthetize further audio samples of the digital audio signal or a new digital audio signal as described before regarding combination of spatializing function 201, filtering function 202 and reproducing function 203.

[0068] Synthetising methods, systems and computer programs, or simply synthetisers, according to present disclosure may be applied in industries and sectors including (but not limited to) entertainment, education, therapy, well-being, analysis and sonification, etc. Similar to how current synthesizers are used as, e.g., musical instruments in combination with and alongside more traditional instruments, synthetisers according to present disclosure may also be used for musical applications in / with extended capacity or more powerful manner. Synthetisers described herein, which provide enhancements regarding synergetic spectral and multi-spatial combinations, increased sensation of immersion, easier direct multidimensional reproduction, may be of particular interest for currently emerging field of 3D or spatial audio. Moreover, synthesizers according to present disclosure may be used by producers and DJs, especially for productions and compositions for spatial audio, and live concerts or shows with 3D audio loudspeaker setups. Naturally, such a synthesizers could also be used in cinema and TV productions to be played in theatres with 3D audio setup, or TV stations or streaming services that offer spatial audio as a service.

[0069] Furthermore, synthetisers according to present disclosure may be used as teaching tool in museums or planetariums, e.g. to demonstrate physics principles or to make educational content more engaging. Heightened immersive effect provided by synthetisers disclosed herein may also allow patients of applicable therapies to immerse themselves more in the sound or environmental acoustic 3D space. In addition, therapeutic effects of Binaural Beats is currently under investigation in several studies, and synthetisers disclosed herein may be used in more powerful manner to create such an illusion and test in deeper and more accurate manner said potential therapeutic effects with upgraded Binaural Beats generated by / through synthetisers disclosed herein. In addition, advantage may be taken from the broad range of user-rulable parameters and enhanced user-sound interaction provided by synthetisers according to present disclosure to, e.g., implement new auditory displays that can present any type of data in novel sonification approach.

[0070] Although only a number of examples have been disclosed herein, other alternatives, modifications, uses and / or equivalents thereof are possible. Furthermore, all possible combinations of the described examples are also covered. Thus, the scope of the disclosure should not be limited by particular examples, but it should be determined only by a fair reading of the claims that follow.

Examples

Embodiment Construction

[0040]Figure 1 is a block diagram schematically illustrating synthetizing systems or synthetisers 100 for three dimensionally (3D) synthetizing a digital audio signal, according to examples. Synthetizing systems 100 may be configured to receive the digital audio signal 112 from, e.g., digital audio signal source 111, and to perform the 3D synthetizing depending on spatial commands 109 and filter instructions 110 from, e.g., user device 108. Synthetizing systems 100 may include a spatializer module 101, a (multidimensional) filterer module 102 and a reproducer module 103.

[0041]Spatializer module 101 may be configured to perform, depending on or as commanded by the spatial commands 109, a spatialization method at audio rate on the digital audio signal 112 to spatialize it and therefore produce a spatialized audio signal 104 whose reproduction implements, in a three dimensional (3D) audible space, spatialized virtual sound sources defined by or including spatial-params. The spatializat...

[0001] The present disclosure relates to methods of three dimensionally synthetizing a digital audio signal, and to systems, computer programs and computing systems suitable for performing said methods.BACKGROUND

[0002] Digital sound / audio synthetisers are known which digitally synthetise input digital audio signal(s) to generate output synthetised digital audio signal(s) whose reproduction results in corresponding sounds or sound effects within audible space. These current synthetisers show limitations or limited aspects whose enhancement may be desirable to implement applications thereof in more optimal or effective manner, or even new applications unknown or non-implementable so far.

[0003] One of these limitations is that current synthetisers yield synthetised audio signals whose reproduction shows low or limited immersivity effect on listeners within audible space. In other words, sound resulting from such a reproduction is received by listeners with rather moderate immersion perception and, therefore, enhancement of said effect may be interesting for applications thereof. Current synthetisers also do not output synthetised audio signals that are (fully) directly reproducible by multidimensional reproduction systems to generate multidimensional sound in multidimensional space. Another limitation is that current synthetisers do not provide users thereof with an instant or near instant interactivity with ongoing sound that is being reproduced within multidimensional space. This (near) instant interactivity between user ruling and running sound may be very interesting in user driven applications in which (near) instant implementation or influence of user instructing into ongoing sound may be very useful. That is, minimum or near-zero delay between user instructing and its reflection into ongoing sound may be especially valuable in certain applications.

[0004] Current synthetisers also offer reduced or limited performance in generation of new (innovative, even unpredictable) sounds over spectral sound-domain combined with spatial sound-domain. Present synthetisers are rather ineffective to synergically combine spectral and multi-spatial sound-domains to generate sounds "never heard before". Improving such a limitation regarding multi-sound-dimensionality in present synthetisers may be an interesting challenge to be faced. Furthermore, already known synthetisers provide reduced or limited range of user-rulable parameters (via, e.g., keys, knobs, sliders or combinations thereof in existing synthetisers), and said limited range necessarily restricts user's capacity of generating sounds and / or influencing ongoing sounds in multidimensional audible space.

[0005] An object of this disclosure is to provide new methods, systems and computer programs aimed at improving prior art manners of three dimensionally synthetizing a digital audio signal.SUMMARY

[0006] In an aspect, methods are provided of three dimensionally synthetizing a digital audio signal depending on spatial commands and filter instructions.

[0007] These methods (also denominated synthetizing methods herein) comprise performing, depending on (or as commanded by) the spatial commands, a spatialization method at audio rate on the digital audio signal to spatialize it and therefore produce a spatialized audio signal whose reproduction implements, in a 3D audible space, spatialized virtual sound sources defined by or including spatial parameters (also herein denominated spatial-params).

[0008] Synthetizing methods further comprise performing, depending on (or as instructed by) the filter instructions, digital filtering on the spatialized audio signal to produce an evolved audio signal whose reproduction implements, in the 3D audible space, evolved virtual sound sources.

[0009] Synthetizing methods still further comprise providing the evolved audio signal to a plurality of loudspeakers or headphones to reproduce the evolved audio signal and, therefore, implement the evolved virtual sound sources in the 3D audible space.

[0010] Audio rate is defined herein as the speed at which (user) control commands (i.e., spatial commands and filter instructions) are processed. More specifically, audio rate relates to the speed at which the audio is sampled digitally or, in other words, the speed at which a new-next digital audio sample is available in the digital audio signal which, in the technical context described herein, is the input signal to be three-dimensionally synthetised by synthetising methods according to present disclosure. This means that new (user) control command(s), or control value(s), is / are processed with every audio sample, i.e. at the same rate as the audio is sampled.

[0011] Such synthetizing methods thus receive one or more (input) digital audio signals and process them to produce one or more (output) evolved or synthetised digital audio signals whose reproduction overcomes at least some of the aforementioned drawbacks related to immersivity effect, direct multidimensional reproduction, user-sound interactivity, synergic spectral and multi-spatial combination, range of user-rulable parameters. Taking this into account, the providing of the evolved or synthetised audio signal(s) to loudspeakers or headphones may be optional, since nuclear aspect of synthetizing methods provided herein is how the one or more (input) digital audio signals are processed to yield the one or more evolved (or synthetised) audio signals whose reproduction implies at least some of the cited 3D-sound-related enhancements.

[0012] Regarding immersivity effect, synthetising methods according to present disclosure provide synthetised audio signal(s) whose reproduction may cause enhanced immersivity effect. This enhancement may be conceptually understood via the fact that such synthetising methods synthetise audio signal(s) with spatialization function at its operational core integrated with digital filtering. Indeed, spatialization at audio rate and digital filtering synergistically cooperate to improve immersivity effect.

[0013] In relation to user-sound interactivity and direct multidimensional reproduction, said aspects may also be enhanced by synthetising methods according to present disclosure. This upgrade may be conceptually understood through the fact that the aforementioned synergistic integration of spatialization at audio rate and digital filtering may imply reduction or even avoidance of processing layers or connections or interfaces in comparison to known assemblies that are mounted or mountable to synthetise sound / audio in 3D audible space

[0014] With respect to two-fold synthetising of sound based on "intimal" combination of spectral and multi-spatial sound-domains, this may be conceptually explained by the fact that the aforementioned combination of spatialization at audio rate and digital filtering in integral or monolithic manner permits influencing ongoing sound (i.e., sound that is being reproduced) from both spectral and multi-spatial perspectives in interlaced manner.

[0015] In reference to range of user-rulable parameters, said aspect may also be enhanced by synthetising methods according to present disclosure since (user-driven) spatial commands influencing spatialization and (user-driven) filter instructions influencing digital filtering may provide the user with a very broad range of user-rulable parameters and combinations thereof.

[0016] In implementations, the spatialization method may be or may include or may be based on Vector Base Amplitude Panning, VBAP, method, or an Ambisonics method, or a Wavefield Synthesis, WFS, method, or a binaural method, or any other known spatialization method for spatializing a digital audio signal in a 3D audible space.

[0017] The performing of the spatialization method may comprise modulating, depending on (or as commanded by) the spatial commands, the spatial-params defining the spatialized virtual sound sources at audio rate. Said modulating may be performed by or may include applying modulating functions to the spatial-params. These spatial-params may comprise one or more of among rotation speed, rotation acceleration, rotation axis orientation, rotation radius, spread or dimensional amplitude of the spatialized virtual sound sources. Such a modulating may cause sound effects such as, e.g., varying frequency split along rotation axes on a one per one basis.

[0018] The applying of modulating functions may comprise applying, depending on (or as commanded by) first spatial commands included in the spatial commands, High Frequency Oscillations (HFOs) on at least some of the spatial-params. Said HFOs may be performed in continuous and uniform manner at audio rate over time with an oscillation or variation rate above (or equal to) 20 Hz. Such a performing of HFOs may cause generation of sound effects such as, e.g., harmonic or non-harmonic spectrum generation or any combination thereof. HFOs ruled / commanded by user (in or through first spatial commands) are just one of the many options the user may have to interact with and, therefore, influence the running sound. Hence, first (or HFO) commands may contribute to provide user with broad range of user-rulable parameters to influence ongoing sound, thereby improving and promoting immersivity effect and synergies in combination of spectral and multi-spatial sound-domains.

[0019] The applying of modulating functions may comprise applying, depending on (or as commanded by) second spatial commands included in the spatial commands, Low Frequency Oscillations (LFOs) on one or more of the spatial-params. Said LFOs may be performed in continuous and uniform manner at audio rate over time with an oscillation or variation rate below (or equal to) 20 Hz. This performing of LFOs may generate sound effects such as, e.g., phase or vibrato or tremolo or frequency shifting or any combination thereof. LFOs ruled / commanded by user (in or through second spatial commands) are just one of the many possibilities the user may have to interact with and, hence, influence the ongoing sound. Then, second (or LFO) commands may help to provide user with very broad set of user-rulable parameters to affect ongoing sound, and this may support improvement and / or promotion of immersivity effect and / or synergetic combination of spectral and multi-spatial sound-domains.

[0020] The applying of modulating functions may comprise applying, depending on (or as commanded by) third spatial commands included in the spatial commands, combination or combinations of oscillations (HFOs and / or LFOs) at audio rate on all or part of the spatial-params. Oscillations (HFOs and / or LFOs) may be combined according to parallel or in-series approach. Parallel approach means that HFOs / LFOs are applied simultaneously (i.e., in parallel). In-series approach means that oscillations (HFOs / LFOs) are applied one after another and, therefore, one oscillation influences / modulates another previously applied oscillation. For example, first HFO / LFO may be applied to a spatial-param, so that the spatial-param starts to oscillate according to said first HFO / LFO; then, second HFO / LFO may be applied to the first HFO / LFO, so that said first HFO / LFO results influenced / modulated by the second HFO / LFO, and so on (e.g., until an n-th HFO / LFO). This performing of combined or mixed oscillations (HFOs / LFOs) may result in complex modulation of the spatial-params affected (by third spatial commands), thereby causing generation of sound effects including, e.g., complex spectra generation. Similar benefits and effects as those explained regarding HFOs (and related first spatial commands) and LFOs (and related second spatial commands) may be attributed or attributable to combination of HFOs and / or LFOs. Indeed, said combinations of oscillations may also contribute to improve limitations of present synthetisers: immersivity effect, user-sound interactivity, synergic spectral and multi-spatial combination, range of user-rulable parameters.

[0021] The applying of modulating functions may comprise applying, depending on (or as commanded by) fourth spatial commands included in the spatial commands, one or more envelopes on at least part of the spatial-params. This enveloping may cause the spatial-params affected (by fourth spatial commands) to change at audio rate over time following a waveform including one or more of among attack phase, hold phase, decay phase, delay phase, sustain phase and release phase. Similar benefits and effects as those explained regarding HFOs (and related first spatial commands), LFOs (and related second spatial commands) and combinations of oscillations (and related third spatial commands) may be attributed or attributable to envelopes (and related fourth spatial commands ruling them). Since envelopes have a temporal beginning and end, which may be defined / triggered by user through fourth spatial commands, user-sound interactivity is further enhanced. In a keyboard-based synthetiser, such beginning and end may be ordered / commanded by user via key pressing and releasing, respectively, in such a manner that said pressing may trigger fourth spatial command indicating beginning and said releasing may trigger fourth spatial command indicating end.

[0022] The above modulations or application of modulating functions based on LFO(s), HFO(s), mixed oscillation(s) and envelope(s) or combination(s) thereof may be performed on corresponding spatial-params per rotation axis or per spatial dimension or both in the 3D audible space. Improvable aspects of current synthetisers (immersivity effect, user-sound interactivity, synergic spectral and multi-spatial combination, range of user-rulable parameters) may be further enhanced with said feature or combination of features.

[0023] The performing of the digital filtering on the spatialized audio signal may comprise applying, depending on (or as instructed by) the filter instructions, one or more digital filters to the spatialized virtual sound sources or, in particular, to spatial region that each of the spatialized virtual sound sources occupies over time. Such digital filters may include one or more of among: High-pass Filter, Low-pass Filter, Band-pass Filter, Band-stop Filter, Notch Filter, All-pass Filter, Equalization Filter, Comb Filter, Amplifier, Compressor, Limiter, Distortion, Delay, Echo, Chorus, Flanger, Reverberation, Blurring, Widening, Sharpening, Mirroring, Rotation, Windowing, Warping. This broad digital filtering (broad in the sense that filtering is implementable in many different manners) may open / extend even more the range of user-rulable parameters through which user may intervene on running sound with zero or near zero delay between user ruling and its reflection on reproducing sound. Such a broadly customizable filtering of spatially distributed or spread sound may also contribute to enhance immersivity effect, as well as the other aspects of present synthetisers that are enhanced by synthetising methods according to present disclosure.

[0024] Each of said digital filters includes filter parameters (also herein denominated filter-params). Said filter-params may include, e.g., Centre Frequency, Gain and Q (Quality), which are filter-params of High-pass Filter or Low-Pass Filter or Band-pass Filter or Band-stop Filter or Notch Filter. In general, aforementioned digital filters may be operated depending on filter-params that are known to influence or characterize their behaviour. Since the filter-params that each of the cited digital filters may have associated are known in the technical field at hand, no more details thereon are provided herein.

[0025] The performing of the digital filtering on the spatialized audio signal may comprise generating or creating, depending on (or as instructed by) first filter instructions included in the filter instructions, spatialized parameters (also herein denominated spatialized-params) or instances thereof. Each of said spatialized-params or instances thereof may include or refer to one of the filter-params (of one of the digital filters to be applied) and one or more associated meta-parameters (also herein denominated filter-meta-params) defining a region of / in the 3D audible space in which its associated filter-param has or will have or can have effect. Different instances of same filter-param may thus have an independent or distinct effect on disjoint or fully or partially overlapping regions in the 3D audible space. Such spatialized-params, mainly their respective filter-meta-params, may especially extend the many manners in which user may influence on running sound. With the spatialized-params, filter-params may be altered not only regarding their values but also spatially, i.e., filter-params' values may be tuned and, additionally, said tuning's effect may be restricted to particular region(s) in the audible 3D space. Limitations of current synthetisers regarding, e.g., immersivity effect, user-sound interactivity, synergic spectral and multi-spatial combination and range of user-rulable parameters may thus be enhanced at least in part due to the proposed spatialized-params and their use. For example, the fact that user can impact not only on filter-params' values but also on particular effect regions within 3D audible space, increases the granularity under / with which user can influence ongoing sound. This increased granularity under / with which user can drive / rule the synthetising of sound may also contribute to improve immersion effect, user-sound interactivity, etc.

[0026] The performing of the digital filtering may comprise setting, depending on (or as instructed by) one or more of the first filter instructions, the filter-meta-params (in spatialized-params) with data defining its associated filter-param's effect region in the 3D audible space. Said filter-meta-params or, in other words, its related effect region data may include or denote or refer to one or more of among: spatial coordinates in the 3D audible space defining said effect region, 2D or 3D angle within rotation circular or spherical bound(s) to which said effect region is restricted, transition rate of the filter-param associated to the filter-meta-param either within said effect region or between different effect regions in the 3D audible space. This setting of filter-meta-params may contribute to improve limitations of prior art synthetisers for same or similar reasons as the ones commented with respect to spatialized-params creation.

[0027] The performing of the digital filtering may comprise applying, depending on (or as instructed by) second filter instructions included in the filter instructions, one or more envelopes on at least some of the filter-params in the spatialized-params. Each of said envelopes may be a localized envelope or a non-localized envelope. A localized envelope may be an envelope with one or more meta-parameters (also herein denominated envelope-meta-params) defining a region of / in the 3D audible space in which said localized envelope has or will have or can have effect. A non-localized envelope may be an envelope not restricted spatially, i.e., without envelope-meta-param(s).

[0028] A localized envelope may be applied to a filter-param to cause its value to vary or, in other words, to be influenced by or according to said localized envelope in spatially restricted manner. If the filter-param is not a spatially restricted filter-param (i.e., with no associated filter-meta-param), then said spatial restriction only depends on the effect region defined by the envelope-meta-param of the localized envelope applied to the filter-param. Otherwise, if the filter-param is a spatially restricted filter-param (i.e., with associated filter-meta-param), then said spatial restriction depends on combination of the effect region defined by the envelope-meta-param and the effect region defined by the filter-meta-param. This combination of both effect regions may be their intersection in the 3D audible space.

[0029] A non-localized envelope may be applied to any of a filter-param's value, a filter-meta-param, an envelope-meta-param, an LFO-meta-param (defined in other parts of the disclosure). Application of non-localized envelope to filter-param implies that the filter-param's value is varied or influenced by said non-localized envelope. Application of non-localized envelope to filter-meta-param implies that the filter-meta-param's effect region is varied or influenced by said non-localized envelope. Application of non-localized envelope to envelope-meta-param implies that the envelope-meta-param's effect region is varied or influenced by said non-localized envelope. Application of non-localized envelope to LFO-meta-param implies that the LFO-meta-param's effect region is varied or influenced by said non-localized envelope.

[0030] With such advanced envelopes (i.e., localized and non-localized envelopes) user's leeway to actuate on in-progress sound may be widened even more. Hence, range of user-ruling parameters is extended and other aspects such as, e.g., immersivity effect, user-sound interactivity, synergic spectral and multi-spatial combination are also accordingly enhanced.

[0031] The performing of the digital filtering may comprise applying, depending on (or as instructed by) third filter instructions included in the filter instructions, one or more Low Frequency Oscillations (LFOs) on at least part of the filter-params in the spatialized-params. Each of said LFOs may be a localized LFO or a non-localized LFO. A localized LFO may be an LFO with one or more meta-parameters (also herein denominated LFO-meta-params) defining a region of / in the 3D audible space in which said localized LFO has or will have or can have effect. A non-localized LFO may be an LFO not restricted spatially, i.e., without LFO-meta-param(s).

[0032] A localized LFO may be applied to a filter-param to cause its value to vary or, in other words, to be influenced by or according to said localized LFO in spatially restricted manner. If the filter-param is not a spatially restricted filter-param (i.e., with no associated filter-meta-param), then said spatial restriction only depends on the effect region defined by the LFO-meta-param of the localized LFO applied to the filter-param. Otherwise, if the filter-param is a spatially restricted filter-param (i.e., with associated filter-meta-param), then said spatial restriction depends on combination of the effect region defined by the LFO-meta-param and the effect region defined by the filter-meta-param. This combination of both effect regions may be their intersection in the 3D audible space.

[0033] A non-localized LFO may be applied to any of a filter-param's value, a filter-meta-param, an envelope-meta-param, an LFO-meta-param. Application of non-localized LFO to filter-param implies that the filter-param's value is varied or influenced by said non-localized LFO. Application of non-localized LFO to filter-meta-param implies that the filter-meta-param's effect region is varied or influenced by said non-localized LFO. Application of non-localized LFO to envelope-meta-param implies that the envelope-meta-param's effect region is varied or influenced by said non-localized LFO. Application of non-localized LFO to LFO-meta-param implies that the LFO-meta-param's effect region is varied or influenced by said non-localized LFO.

[0034] With such advanced LFOs (i.e., localized and non-localized LFOs) user's capacity to influence on in-progress sound may be even further extended for similar reasons as the ones provided in relation to localized and non-localized envelopes.

[0035] In a further aspect, systems are provided for three dimensionally synthetizing a digital audio signal depending on spatial commands and filter instructions. Such systems (also denominated synthetizing systems herein) comprise a spatializer module, a filterer module and a reproducer module. The spatializer module is configured to perform, depending on (or as commanded by) the spatial commands, a spatialization method at audio rate on the digital audio signal to spatialize it and therefore produce a spatialized audio signal whose reproduction implements, in a three dimensional, 3D, audible space, spatialized virtual sound sources defined by or including spatial-params. The filterer module is configured to perform, depending on (or as instructed by) the filter instructions, digital filtering on the spatialized audio signal to produce an evolved audio signal whose reproduction implements, in the 3D audible space, evolved virtual sound sources. The reproducer module is (or may be) configured to provide the evolved audio signal to a plurality of loudspeakers or headphones to reproduce the evolved audio signal and, therefore, implement the evolved virtual sound sources in the 3D audible space.

[0036] Synthetizing systems are suitable or configured to perform synthetizing methods proposed herein, so same or similar functional principles and advantages as the ones described with reference to synthetizing methods may be attributed to such synthetizing systems.

[0037] In a still further aspect, computer programs are provided comprising program instructions for causing a system or computer system to perform synthetizing methods of three dimensionally synthetizing a digital audio signal, such as those described in other parts of the disclosure. These computer programs (also denominated synthetizing computer programs herein) may be embodied on a storage medium and / or carried on a carrier signal. Since synthetizing computer programs are suitable or configured to perform synthetizing methods proposed herein, same or similar functional fundamentals and advantages as the ones described with reference to synthetizing methods may be attributed to such synthetizing computer programs.

[0038] In a yet further aspect, computing systems are provided for three dimensionally synthetizing a digital audio signal, said computing systems comprising a memory and a processor, embodying instructions stored in the memory and executable by the processor, and the instructions comprising functionality or functionalities to execute methods of three dimensionally synthetizing a digital audio signal such as those described in other parts of the disclosure. Such computing systems (also denominated synthetizing computing systems herein) are suitable or configured to perform synthetizing methods described herein, so same or similar functional principles and advantages as the ones described with reference to synthetizing methods may be attributed to such synthetizing computing systems.BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Non-limiting examples of the disclosure will be described in the following, with reference to the appended drawings, in which: Figure 1 is a block diagram schematically illustrating synthetizing systems for three dimensionally synthetizing a digital audio signal, according to examples. Figure 2 is a flow chart schematically illustrating synthetizing methods of three dimensionally synthetizing a digital audio signal, according to examples. DETAILED DESCRIPTION OF EXAMPLES

[0040] Figure 1 is a block diagram schematically illustrating synthetizing systems or synthetisers 100 for three dimensionally (3D) synthetizing a digital audio signal, according to examples. Synthetizing systems 100 may be configured to receive the digital audio signal 112 from, e.g., digital audio signal source 111, and to perform the 3D synthetizing depending on spatial commands 109 and filter instructions 110 from, e.g., user device 108. Synthetizing systems 100 may include a spatializer module 101, a (multidimensional) filterer module 102 and a reproducer module 103.

[0041] Spatializer module 101 may be configured to perform, depending on or as commanded by the spatial commands 109, a spatialization method at audio rate on the digital audio signal 112 to spatialize it and therefore produce a spatialized audio signal 104 whose reproduction implements, in a three dimensional (3D) audible space, spatialized virtual sound sources defined by or including spatial-params. The spatialization method may be (or may include or may be based on) Vector Base Amplitude Panning, VBAP, method, or an Ambisonics method, or a Wavefield Synthesis, WFS, method, or a binaural method, or any other known spatialization method suitable for spatializing a digital audio signal in a 3D audible space.

[0042] In examples, the performing of the spatialization method may comprise modulating, depending on the spatial commands 109, the spatial-params defining the spatialized virtual sound sources. Such a modulating may be performed at audio rate to keep coherence with whole synthetising process. The spatial-params may comprise rotation speed, or rotation acceleration, or rotation axis orientation, or rotation radius, or spread or dimensional amplitude of the spatialized virtual sound sources.

[0043] The modulating of the spatial-params may comprise applying, depending on spatial commands 109, different types of modulations or applications of modulating functions such as, e.g., How Frequency Oscillations (HFOs), Low Frequency Oscillations (LFOs), combinations of HFOs and / or LFOs, envelopes, etc., or any combination thereof on spatial-params. Such modulating functions including HFOs, LFOs, HFO-LFO combinations, envelopes, etc. are properly described functionally and technically in other parts of the disclosure, so no more details thereon are provided here for reasons of redundancy avoidance. HFOs may be user-commanded via first spatial commands indicating said modulating function and parameters thereof defining how and / or according to which conditions said modulating function is to be performed. LFOs may be user-commanded via second spatial commands indicating said modulating function and parameters thereof defining how and / or according to which conditions said modulating function is to be performed. Combinations of HFOs and LFOs may be user-commanded via third spatial commands indicating said modulating function and parameters thereof defining how and / or according to which conditions said modulating function is to be performed. Envelopes may be user-commanded via fourth spatial commands indicating said modulating function and parameters thereof defining how and / or according to which conditions said modulating function is to be performed.

[0044] First, second, third and fourth spatial commands instructing the spatializer module 101 to perform such modulations or modulating functions may include single-modulation commands and multi-modulation commands. Single-modulation command may correspond to spatial command instructing (the spatializer module 101) to perform only one of the cited modulations or modulating functions. Multi-modulation command may correspond to spatial command instructing (the spatializer module 101) to perform several of the cited modulations at same time, or delayed from each other, or weighted combined, etc.

[0045] First, second, third and fourth multi-modulation spatial commands may not be disjoint multi-modulation spatial commands, since same type of modulation (i.e., HFO, LFO, HFO-LFO combination, envelope) may be commanded by any of said first, second, third and fourth multi-modulation spatial commands in combination with other types of modulating functions. Flexibility of these proposed multi-modulation spatial commands is clear, which may permit generating synthetized sounds never experienced before.

[0046] Multidimensional filterer module 102 may be configured to perform, depending on or as instructed by the filter instructions 110, digital filtering of the spatialized audio signal 104 to produce an evolved or synthetised audio signal 105 whose reproduction implements, in the 3D audible space, evolved virtual sound sources. Such a performing of the digital filtering may include applying, depending on the filter instructions, one or more digital filters to the spatialized virtual sound sources or, in particular, to spatial region that each of the spatialized virtual sound sources occupies over time. Each of said digital filters includes filter-params through which behaviour or operation of the digital filter may be ruled.

[0047] Digital filters that are applicable to the spatialized audio signal 104 and, therefore, to the spatialized virtual sound sources one or more of among: High-pass Filter, Low-pass Filter, Band-pass Filter, Band-stop Filter, Notch Filter, All-pass Filter, Equalization Filter, Comb Filter, Amplifier, Compressor, Limiter, Distortion, Delay, Echo, Chorus, Flanger, Reverberation, Blurring, Widening, Sharpening, Mirroring, Rotation, Windowing, Warping. Filter-params through which behaviour or operation of each of said digital filters may be ruled are already known, so no further details thereon are provided.

[0048] The performing of the digital filtering may comprise performing, depending on or as instructed by filter instructions 110, different types of filter-related functions. Examples of filter-related functions are: creation of spatialized-params or instances thereof; setting of filter-meta-params of / in spatialized-params; spatially restricted enveloping (localized enveloping) of filter-param values of / in spatialized-params; spatially non-restricted enveloping (non-localized enveloping) of filter-param values, filter-meta-params, envelope-meta-params, LFO-meta-params, etc.; spatially restricted LFO application (localized LFOs) to filter-param values of / in spatialized-params; spatially non-restricted LFO application (non-localized LFOs) to filter-param values, filter-meta-params, envelope-meta-params, LFO-meta-params, etc. Since said filter-related functions are properly described functionally and technically in other parts of the disclosure, no more details thereon are provided here for reasons of redundancy avoidance.

[0049] Filter-related functions of creating spatialized-params and of setting filter-meta-params may be user-instructed via first filter instructions indicating the filter-related function to be performed and parameters thereof defining how and / or according to which conditions the indicated filter-related function is to be performed. Filter-related functions of localized enveloping and of non-localized enveloping may be user-instructed via second filter instructions indicating the filter-related function to be performed and parameters thereof defining how and / or according to which conditions the indicated filter-related function is to be performed. Filter-related functions of localized LFO application and of non-localized LFO application may be user-instructed via third filter instructions indicating the filter-related function to be performed and parameters thereof defining how and / or according to which conditions the indicated filter-related function is to be performed.

[0050] First, second and third filter instructions commanding the (multidimensional) filterer module 102 to perform such filter-related functions may include single-function instructions and multi-function instructions. Single-function instruction may correspond to filter instruction commanding (the filterer module 102) to perform only one of the cited filter-related functions. Multi-function instruction may correspond to filter instruction commanding (the multidimensional filterer module 102) to perform several of the cited filter-related functions at same time, or delayed from each other, or weighted combined, etc.

[0051] First, second and third multi-function filter instructions may not be disjoint multi-function filter instructions, since same type of filter-related function (i.e., creation of spatialized-params, setting of filter-meta-params, localized enveloping non-localized enveloping, localized LFO application, non-localized LFO application) may be instructed by any of said first, second and third multi-function filter instructions in combination with other types of filter-related functions. Flexibility of these proposed multi-function filter instructions is clear, which may permit generating synthetized sounds never undergone before.

[0052] Reproducer module 103 may be configured to provide the evolved or synthetised audio signal 105 to a plurality of loudspeakers (or headphones) 107 to reproduce the evolved audio signal 106 and, therefore, implement the evolved virtual sound sources in the 3D audible space. If some kind of encoding has been performed in the spatialization of the digital audio signal and / or in the digital filtering of the spatialized audio signal, reproducer module 103 may include a decoder to decode the encoded filtered spatialized audio signal, so that it is reproducible by loudspeakers (or headphones) 107.

[0053] As used herein, the term "module" may be understood to refer to software, firmware, hardware and / or various combinations thereof. It is noted that the modules are exemplary. The modules may be combined, integrated, separated, and / or duplicated to support various applications. Also, a function described herein as being performed by a particular module may be performed by one or more other modules and / or by one or more other devices instead of or in addition to the function performed by the described particular module.

[0054] The modules may be implemented across multiple devices, associated or linked to corresponding synthetizing systems proposed herein, and / or to other components that may be local or remote to one another. Additionally, the modules may be moved from one device and added to another device, and / or may be included in both devices, associated to corresponding synthetizing systems proposed herein. Any software implementations may be tangibly embodied in one or more storage media, such as, e.g., a memory device, a floppy disk, a compact disk (CD), a digital versatile disk (DVD), or other devices that may store computer code.

[0055] Synthetizing systems according to present disclosure may be implemented by computing means, electronic means or a combination thereof. The computing means may be a set of instructions (e.g., a computer program) and then synthetizing systems may comprise a memory and a processor, embodying said set of instructions stored in the memory and executable by the processor. These instructions may comprise functionality or functionalities to execute corresponding synthetizing methods such as those described in other parts of the disclosure.

[0056] In synthetizing systems implemented only by electronic means, a controller of the system may be, for example, a CPLD (Complex Programmable Logic Device), an FPGA (Field Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit).

[0057] In synthetizing systems that are a combination of electronic and computing means, the computing means may be a set of instructions (e.g., a computer program) and the electronic means may be any electronic circuit capable of implementing corresponding steps of synthetizing methods proposed herein, such as those described in other parts of the disclosure.

[0058] The computer programs may be embodied in / on a storage medium (for example, a CD-ROM, a DVD, a USB drive, a computer memory or a read-only memory) or carried on a carrier signal (for example, on an electrical or optical carrier signal).

[0059] The computer programs may be in the form of source code, object code, a code intermediate source and object code such as in partially compiled form, or in any other form suitable for use in implementing synthetizing methods according to present disclosure. The carrier may be any entity or device capable of carrying the computer programs.

[0060] For example, the carrier may comprise a storage medium, such as a ROM, for example a CD ROM or a semiconductor ROM, or a magnetic recording medium, for example a hard disk. Further, the carrier may be a transmissible carrier such as an electrical or optical signal, which may be conveyed via electrical or optical cable or by radio or other means.

[0061] When the computer programs is / are embodied in a signal that may be conveyed directly by a cable or other device or means, the carrier may be constituted by such cable or other device or means. Alternatively, the carrier may be an integrated circuit in which the computer programs is / are embedded, the integrated circuit being adapted for performing, or for use in the performance of, synthetizing methods proposed herein.

[0062] Figure 2 is a flow chart schematically illustrating synthetizing methods of three dimensionally synthetizing a digital audio signal depending on spatial commands and filter instructions, according to examples. Since synthetizing methods according to Figure 2 are performable by or at synthetizing systems according to Figure 1, number references from said Figure 1 may be reused in following description of Figure 2.

[0063] Synthetizing methods may be initiated (e.g., at block 200) upon detection of a starting condition such as, e.g., a user request to start the synthetizing method.

[0064] Synthetizing methods may further include (e.g., at method-block 201) performing, depending on the spatial commands, a spatialization method at audio rate on the digital audio signal to spatialize it and therefore produce a spatialized audio signal whose reproduction implements, in a 3D audible space, spatialized virtual sound sources defined by or including spatial-params. This spatializing functionality implemented or implementable at method-block 201 may be performed by, e.g., spatializer module 101 as previously described with reference to Figure 1. Functional details and considerations explained about spatializer module 101 may thus be similarly attributed or attributable to method-block 201.

[0065] Synthetizing methods may still further include (e.g., at method-block 202) performing, depending on the filter instructions, multidimensional digital filtering on the spatialized audio signal to produce an evolved audio signal whose reproduction implements, in the 3D audible space, evolved virtual sound sources. This filtering functionality implemented or implementable at method-block 202 may be performed by, e.g., multidimensional filterer module 102 previously described with reference to Figure 1. Functional details and considerations explained about multidimensional filterer module 102 may thus be similarly attributed or attributable to method-block 202.

[0066] Synthetizing methods may yet further include (e.g., at method-block 203) providing the evolved audio signal to a plurality of loudspeakers or headphones to reproduce the evolved audio signal and, therefore, implement the evolved virtual sound sources in the 3D audible space. This reproducing functionality implemented or implementable at method-block 203 may be performed by, e.g., reproducer module 103 previously described with reference to Figure 1. Functional details and considerations explained about reproducer module 103 may thus be similarly attributed or attributable to method-block 203.

[0067] Synthetizing methods may additionally include (e.g., at decision block 204) verifying whether an ending condition occurs or is satisfied. In case of positive or true result Y of said verification, synthetizing method may proceed to method-block 205 to terminate execution of the method. Otherwise N, synthetizing method may loop back to previous method-block 201 to perform a new iteration to, e.g., synthetize further audio samples of the digital audio signal or a new digital audio signal as described before regarding combination of spatializing function 201, filtering function 202 and reproducing function 203.

[0068] Synthetising methods, systems and computer programs, or simply synthetisers, according to present disclosure may be applied in industries and sectors including (but not limited to) entertainment, education, therapy, well-being, analysis and sonification, etc. Similar to how current synthesizers are used as, e.g., musical instruments in combination with and alongside more traditional instruments, synthetisers according to present disclosure may also be used for musical applications in / with extended capacity or more powerful manner. Synthetisers described herein, which provide enhancements regarding synergetic spectral and multi-spatial combinations, increased sensation of immersion, easier direct multidimensional reproduction, may be of particular interest for currently emerging field of 3D or spatial audio. Moreover, synthesizers according to present disclosure may be used by producers and DJs, especially for productions and compositions for spatial audio, and live concerts or shows with 3D audio loudspeaker setups. Naturally, such a synthesizers could also be used in cinema and TV productions to be played in theatres with 3D audio setup, or TV stations or streaming services that offer spatial audio as a service.

[0069] Furthermore, synthetisers according to present disclosure may be used as teaching tool in museums or planetariums, e.g. to demonstrate physics principles or to make educational content more engaging. Heightened immersive effect provided by synthetisers disclosed herein may also allow patients of applicable therapies to immerse themselves more in the sound or environmental acoustic 3D space. In addition, therapeutic effects of Binaural Beats is currently under investigation in several studies, and synthetisers disclosed herein may be used in more powerful manner to create such an illusion and test in deeper and more accurate manner said potential therapeutic effects with upgraded Binaural Beats generated by / through synthetisers disclosed herein. In addition, advantage may be taken from the broad range of user-rulable parameters and enhanced user-sound interaction provided by synthetisers according to present disclosure to, e.g., implement new auditory displays that can present any type of data in novel sonification approach.

[0070] Although only a number of examples have been disclosed herein, other alternatives, modifications, uses and / or equivalents thereof are possible. Furthermore, all possible combinations of the described examples are also covered. Thus, the scope of the disclosure should not be limited by particular examples, but it should be determined only by a fair reading of the claims that follow.

Examples

Embodiment Construction

[0040]Figure 1 is a block diagram schematically illustrating synthetizing systems or synthetisers 100 for three dimensionally (3D) synthetizing a digital audio signal, according to examples. Synthetizing systems 100 may be configured to receive the digital audio signal 112 from, e.g., digital audio signal source 111, and to perform the 3D synthetizing depending on spatial commands 109 and filter instructions 110 from, e.g., user device 108. Synthetizing systems 100 may include a spatializer module 101, a (multidimensional) filterer module 102 and a reproducer module 103.

[0041]Spatializer module 101 may be configured to perform, depending on or as commanded by the spatial commands 109, a spatialization method at audio rate on the digital audio signal 112 to spatialize it and therefore produce a spatialized audio signal 104 whose reproduction implements, in a three dimensional (3D) audible space, spatialized virtual sound sources defined by or including spatial-params. The spatializat...

Claims

1. Method of three dimensionally synthetizing a digital audio signal depending on spatial commands and filter instructions, the method comprising performing, depending on or as commanded by the spatial commands, a spatialization method at audio rate on the digital audio signal to spatialize it and therefore produce a spatialized audio signal whose reproduction implements, in a three dimensional, 3D, audible space, spatialized virtual sound sources defined by or including spatial parameters; performing, depending on or as instructed by the filter instructions, digital filtering on the spatialized audio signal to produce an evolved or synthetised audio signal whose reproduction implements, in the 3D audible space, evolved virtual sound sources; and providing the evolved audio signal to a plurality of loudspeakers or headphones to reproduce the evolved audio signal and, therefore, implement the evolved virtual sound sources in the 3D audible space.

2. Method of three dimensionally synthetizing a digital audio signal according to claim 1, wherein the spatialization method is or includes or is based on Vector Base Amplitude Panning, VBAP, method, or an Ambisonics method, or a Wavefield Synthesis, WFS, method, or a binaural method, or any other known spatialization method for spatializing a digital audio signal in a 3D audible space.

3. Method of three dimensionally synthetizing a digital audio signal according to any of claims 1 or 2, wherein the performing of the spatialization method comprises modulating, depending on the spatial commands, the spatial parameters defining the spatialized virtual sound sources, said modulating being performed by applying at audio rate modulating functions to the spatial parameters.

4. Method of three dimensionally synthetizing a digital audio signal according to claim 3, wherein the spatial parameters comprise one or more of among rotation speed, rotation acceleration, rotation axis orientation, rotation radius, spread or dimensional amplitude of the spatialized virtual sound sources.

5. Method of three dimensionally synthetizing a digital audio signal according to any of claims 3 or 4, wherein the applying of modulating functions comprises applying, depending on first spatial commands included in the spatial commands, one or more High Frequency Oscillations, HFO(s), to at least some of the spatial parameters in continuous and uniform manner at audio rate over time with an oscillation or variation rate above or equal 20 Hz; and / or applying, depending on second spatial commands included in the spatial commands, one or more Low Frequency Oscillations, LFO(s), to one or more of the spatial parameters in continuous and uniform manner at audio rate over time with an oscillation or variation rate below or equal to 20 Hz; and / or applying, depending on third spatial commands included in the spatial commands, combination or combinations of one or more HFOs and / or one or more LFOs at audio rate to all or part of the spatial parameters; and / or applying, depending on fourth spatial commands included in the spatial commands, one or more envelopes at audio rate to at least part of the spatial parameters to cause them to change over time following a waveform including one or more of among attack phase, hold phase, decay phase, delay phase, sustain phase and release phase.

6. Method of three dimensionally synthetizing a digital audio signal according to any of claims 3 to 5, wherein the modulating functions are applied to the spatial parameters per rotation axis or per spatial dimension or both in the 3D audible space.

7. Method of three dimensionally synthetizing a digital audio signal according to any of claims 1 to 6, wherein the performing of the digital filtering on the spatialized audio signal comprises applying, depending on the filter instructions, one or more digital filters to the spatialized virtual sound sources, each of said digital filters including filter parameters.

8. Method of three dimensionally synthetizing a digital audio signal according to claim 7, wherein the one or more digital filters includes one or more of among: High-pass Filter, Low-pass Filter, Band-pass Filter, Band-stop Filter, Notch Filter, All-pass Filter, Equalization Filter, Comb Filter, Amplifier, Compressor, Limiter, Distortion, Delay, Echo, Chorus, Flanger, Reverberation, Blurring, Widening, Sharpening, Mirroring, Rotation, Windowing, Warping.

9. Method of three dimensionally synthetizing a digital audio signal according to any of claims 7 or 8, wherein the performing of the digital filtering comprises generating or creating, depending on first filter instructions included in the filter instructions, one or more spatialized parameters or instances thereof, each of said spatialized parameters or instances thereof including or referring to one of the filter parameters of one of the digital filters to be applied and an associated meta parameter defining a region of / in the 3D audible space in which its associated filter parameter has or will have or can have effect.

10. Method of three dimensionally synthetizing a digital audio signal according to claim 9, wherein the performing of the digital filtering comprises setting, depending on one or more of the first filter instructions, the meta parameters in the spatialized parameters with data defining its associated filter parameter's effect region in the 3D audible space, said data including one or more of among: spatial coordinates in the 3D audible space defining said effect region, 2D or 3D angle within rotation circular or spherical bound to which said effect region is restricted, transition rate of the filter parameter linked to its associated meta parameter within said effect region or between different effect regions in the 3D audible space.

11. Method of three dimensionally synthetizing a digital audio signal according to any of claims 9 or 10, wherein the performing of the digital filtering comprises applying, depending on second filter instructions included in the filter instructions, one or more envelopes on at least some of the filter parameters in the spatialized parameters, each of said envelopes being a localized envelope or a non-localized envelope; wherein a localized envelope is an envelope restricted spatially, with one or more envelope meta parameters defining a region of / in the 3D audible space in which said localized envelope has or will have or can have effect, and a non-localized envelope is an envelope not restricted spatially, with no envelope meta parameter.

12. Method of three dimensionally synthetizing a digital audio signal according to any of claims 9 to 11, wherein the performing of the digital filtering comprises applying, depending on third filter instructions included in the filter instructions, one or more Low Frequency Oscillations, LFO(s), on at least some of the filter parameters in the spatialized parameters, each of said LFOs being a localized LFO or a non-localized LFO; wherein a localized LFO is an LFO restricted spatially, with one or more LFO meta parameters defining a region of / in the 3D audible space in which said localized LFO has or will have or can have effect, and a non-localized LFO is an LFO not restricted spatially, with no LFO meta parameter.

13. Computer program comprising computer program code means adapted to perform all the steps of the method according to any of claims 1-12 when said program is run on a computer system.

14. Computer program according to claim 13, embodied on a computer readable medium.

15. System for three dimensionally synthetizing a digital audio signal depending on spatial commands and filter instructions, the system comprising a spatializer module configured to perform, depending on or as commanded by the spatial commands, a spatialization method at audio rate on the digital audio signal to spatialize it and therefore produce a spatialized audio signal whose reproduction implements, in a three dimensional, 3D, audible space, spatialized virtual sound sources defined by or including spatial parameters; a filterer module configured to perform, depending on or as instructed by the filter instructions, digital filtering on the spatialized audio signal to produce an evolved audio signal whose reproduction implements, in the 3D audible space, evolved virtual sound sources; and a reproducer module configured to provide the evolved audio signal to a plurality of loudspeakers or headphones to reproduce the evolved audio signal and, therefore, implement the evolved virtual sound sources in the 3D audible space.

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