Modal reverberation effects in acoustic space

Abstract

A method and system for performing modified reverberation techniques on an audio signal is described. The method may involve receiving an audio signal, a modal reverberation effect to be applied to the audio signal, and an indication of a plurality of frequencies. The vibration modes of a space to be simulated by the reverberation effect may be separated into a set of frequencies that are included in the input and a set of frequencies that are not included in the input. The modal reverberation effect may be modified by individually adjusting the separated sets of vibration modes. The modified effect may then be applied to the audio signal.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application is a continuation of U.S. Patent Application No. 16 / 585,036, filed September 27, 2019, the disclosure of which is incorporated herein by reference. [Background technology]

[0002] Audio engineers, musicians, and even the general public (collectively "users") are familiar with creating and manipulating audio signals. For example, audio engineers edit stereo signals by mixing mono audio signals together using effects such as pan and gain to position the mono audio signals within the stereo field. Users also manipulate individual components of audio signals for effect, processing them using multiband structures such as crossover networks for multiband processing. In addition, musicians and audio engineers regularly use audio effects such as compression, distortion, delay, reverberation, and the like to create acoustically pleasing and sometimes unpleasant sounds. Audio signal manipulation is usually performed using specialized software or hardware. The type of hardware and software used to manipulate audio signals generally depends on the user's wishes. Users are constantly looking for new ways to create and manipulate audio signals.

[0003] Reverberation is one of the most common effects that users apply to audio signals. The reverberation effect simulates the reverberation of a particular room or acoustic space, so that the audio signal sounds as if it was recorded in a room with a particular impulse response.

[0004] One way to apply reverberation to an audio signal is to use a technique called convolution. Convolution reverberation applies the impulse response of a given acoustic space to the audio signal, so that the audio signal sounds as if it was generated in that given space. However, techniques for manipulating the parameters of convolution reverberation are relatively limited. For example, using convolution reverberation, it may not be possible to isolate and manipulate a single frequency resonance in the audio signal. In addition, using convolution reverberation, it may not be possible to adjust or manipulate a single characteristic of the simulated physical space (e.g., the length of the space, the width of the space).

[0005] An alternative way of applying reverberation to an audio signal is to use a technique called modal reverb. Unlike convolutional reverberation, modal reverberation analyzes the impulse response of a given space, identifies vibration modes in the given space based on this analysis, and then synthesizes the individual vibration modes of the space. As a result, individual frequencies of the reverberation can be edited in isolation, and techniques that manipulate the parameters of modal reverberation are more robust than techniques that manipulate the parameters of convolutional reverberation techniques.

[0006] One challenge in audio production arises in audio signals with many instruments playing simultaneously with reverberation. The reverberation may be a characteristic of the situation in which the audio signal was recorded, or it may be added by audio engineering. In either case, it may be difficult to balance these various audio signal sources with each other, especially when they have reverberation.

[0007] Currently available products for audio signal manipulation and equalization allow the user to equalize either the input signal or the output signal. In some cases, the impulse response applied to the audio signal can be equalized. However, in all such cases, the overlap between multiple audio signal sources prevents the known equalizers from balancing the audio signal sources. Summary of the Invention

[0008] The present technology relates to a system for controlling the characteristics of a reverberation effect applied to an audio signal. The present technology also relates to a software application for managing such a system to improve the resulting signal and, optionally, to interface with a user to give the user more control over the reverberation effect and the resulting signal. This can improve on known reverberation techniques by individually controlling specific frequencies at which one or more audio signal sources are known to reverberate. In some cases, when a reverberation effect is applied, the energy of the audio signal at those specific frequencies can be selectively reduced so that the applied reverberation enhances the signal rather than clashing with the audio source. In other cases, when a reverberation effect is applied, the energy at specific frequencies can be selectively boosted to give the impression of an audio source that is equally tempered. Other example effects are described herein.

[0009] The technology can be implemented on a computer or network of computers in the form of software or machine instructions on a server or electronic device that communicates with an application on the electronic device. The computer or network of computers can include one or more processors and a memory that stores one or more programs configured to be executed by the one or more processors. The memory can further store data used in executing the one or more programs. In operation, the one or more programs can receive an audio signal and input from a user, and can adjust characteristics of a reverberation effect applied to the audio signal based on the user input.

[0010] When a modal reverberation effect is applied to an audio signal, the modal reverberation effect can be generated by calculating individual vibration modes of the acoustic space from an analysis of the impulse response of the acoustic space. Each vibration mode can include a modal frequency and a mode shape. The one or more programs can then adjust the mode shape of the particular vibration mode that corresponds to the frequency indicated by the user input. Adjusting the mode shape can involve reducing or increasing the energy of the particular vibration mode in the modal reverberation effect, depending on the effect desired by the user. The modified modal reverberation effect can then be applied to the audio signal.

[0011] A similar concept can be applied to modify a convolutional reverberation effect applied to an audio signal, in which the impulse response of the acoustic space can be transformed using a Fast Fourier Transform (FFT) to represent the acoustic space in the frequency domain, and portions of the frequency domain signal that correspond to one or more frequencies of the user input can be adjusted.

[0012] The user input may include one or more frequencies. The frequencies may correspond to frequencies of a collection of notes played in the recording. The collection of notes may be the key of the recording, a scale, or one or more instruments played in the recording. In some cases, the one or more frequencies may include harmonics of the notes (e.g., second harmonics, etc.) and inharmonic frequencies of the notes.

[0013] In operation, the system can be used to achieve a reverberation effect on an audio signal without adding energy that is inconsistent with some instruments in the audio signal. For example, if a user wishes to apply a reverberation effect to an audio recording in which a piano is being played (among other instruments and / or sounds), the user can provide the audio recording to the system, select the desired reverberation effect, and further select "piano" as a user input. The program can then modify the selected reverberation effect based on specific frequencies associated with the "piano" input (e.g., piano notes, harmonics, etc.). The selected reverberation effect can be attenuated at or near the specific frequencies of the user input so as not to interfere with the sounds of other instruments in the recording. This achieves a reverberation effect that is applied to the recording, but in a way that envelopes and enhances the piano sounds without causing inconsistencies with the other instruments.

[0014] In another example, instead of selecting a particular instrument, a user may select a key, such as C major, in which case the energy of the selected reverb effect may be attenuated at or near frequencies associated with the key of C major, while maintaining the energy of the reverb effect at the remaining frequencies.

[0015] In another example, instead of attenuating the energy of a selected reverberation effect at certain frequencies, the energy can be boosted at certain frequencies to create the effect of an equally tempered instrument or acoustic space.

[0016] One aspect of the disclosure provides a method executed by one or more processors, comprising: receiving an audio signal; receiving a modal reverberation effect to be applied to the audio signal, the modal reverberation effect including one or more vibration modes of a given acoustic space, each vibration mode having a corresponding modal frequency; determining a plurality of frequencies for modifying the modal reverberation effect; generating a first set and a second set of vibration modes from the one or more vibration modes of the modal reverberation effect, each vibration mode in the first set having a modal frequency corresponding to one of the plurality of frequencies and each vibration mode in the second set having a modal frequency not corresponding to any of the plurality of frequencies; modifying the modal reverberation effect by adjusting the first set of vibration modes of the modal reverberation effect in isolation from the second set of vibration modes of the modal reverberation effect; and applying the modified modal reverberation effect to the audio signal.

[0017] In some examples, the plurality of frequencies may correspond to the frequencies of notes of a chromatic scale within a specified range. In some examples, the plurality of frequencies may include two or more frequencies corresponding to notes of a microtonal scale. In some examples, the plurality of frequencies may correspond to a subset of the frequencies of notes of a chromatic scale. The step of determining a plurality of frequencies for modifying the modal reverberation effect may involve receiving, by the one or more processors, an input indicative of a musical tonality or a musical scale, each of the plurality of frequencies corresponding to a frequency of a note included in the musical tonality or the musical scale. Additionally or alternatively, the step of determining a plurality of frequencies for modifying the modal reverberation effect may involve receiving, by the one or more processors, an input indicative of one or more musical instruments, the plurality of frequencies being associated with the one or more musical instruments. The one or more musical instruments may include any one or combination of a piano having a plurality of keys, each key corresponding to a frequency, the plurality of frequencies including the corresponding frequencies of the keys, and a guitar having a plurality of strings, each string having a plurality of frets, each fret of each string corresponding to a frequency, the plurality of frequencies including the corresponding frequencies of the frets.

[0018] In some examples, the multiple frequencies can include one or more fundamental frequencies and harmonics of the fundamental frequencies. In some examples, adjusting the first set of modes can involve adjusting a mode shape of each mode in the first set of modes, e.g., reducing, by the one or more processors, an energy of each mode in the first set of modes, or increasing, by the one or more processors, an energy of each mode in the first set of modes, etc.

[0019] In some examples, determining a plurality of frequencies that modify the modal reverberation effect may involve deriving, by the one or more processors, the plurality of frequencies from an analysis of the audio signal.

[0020] Another aspect of the disclosure provides a system comprising one or more processing devices and a memory storing one or more programs configured to be executed by the one or more processing devices, the one or more programs including instructions executed by the one or more processing devices to receive an audio signal, a modal reverberation effect to be applied to the audio signal, the modal reverberation effect including one or more vibration modes of a given acoustic space, each vibration mode having a corresponding modal frequency, determine a plurality of frequencies for modifying the modal reverberation effect, generate a first set and a second set of vibration modes from the one or more vibration modes of the modal reverberation effect, each vibration mode in the first set having a modal frequency corresponding to one of the plurality of frequencies and each vibration mode in the second set having a modal frequency not corresponding to any of the plurality of frequencies, modifying the modal reverberation effect by adjusting the first set of vibration modes of the modal reverberation effect in isolation from the second set of vibration modes of the modal reverberation effect, and applying the modified modal reverberation effect to the audio signal.

[0021] In some examples, the multiple frequencies can correspond to the frequencies of chromatic notes within a specified range. In some examples, the multiple frequencies can include two or more frequencies corresponding to microtonal notes. The multiple frequencies can correspond to a subset of the frequencies of chromatic notes. The one or more processing devices can be configured to receive an input indicative of a musical tonality or musical scale, each of the multiple frequencies corresponding to a frequency of a note included in the musical tonality or musical scale. Additionally or alternatively, the one or more processing devices can be configured to receive an input indicative of one or more musical instruments, the multiple frequencies being associated with the one or more musical instruments. The one or more musical instruments can include any one or combination of a piano having multiple keys, each key corresponding to a frequency, the multiple frequencies including the corresponding frequencies of the keys, and a guitar having multiple strings, each string having multiple frets, each fret of each string corresponding to a frequency, the multiple frequencies including the corresponding frequencies of the frets.

[0022] In some examples, the multiple frequencies may include one or more fundamental frequencies and harmonics of the fundamental frequency.

[0023] In some examples, the one or more processing devices may be configured to adjust the mode shape of each mode in the first set of modes, for example, by adjusting the mode shape to reduce the energy of each mode in the first set of modes, or by adjusting the mode shape to increase the energy of each mode in the first set of modes.

[0024] In some examples, the one or more processing devices may be configured to analyze the audio signal and determine at least one of a tonality, a scale, or an instrument of the audio signal based on the analysis, and the determined frequencies that modify the modal reverberation effect may correspond to frequencies of the determined tonality, scale, or instrument.

[0025] The above aspects, features and advantages of the present invention will be further understood upon consideration of the following description of exemplary embodiments and the accompanying drawings, in which like reference numerals represent like elements. In describing the embodiments of the present invention illustrated in the drawings, specific terminology may be used for the sake of clarity. However, it is not intended that aspects of the present invention be limited to the specific terminology used. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a block diagram of an example system according to an aspect of the present disclosure. [Diagram 2] FIG. 2 is a flow diagram of an exemplary method according to an aspect of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] FIG. 1 illustrates an exemplary system 100 for performing the modal reverberation techniques described in this application. The system 100 may include one or more processing devices 110 configured to execute a set of instructions or executable programs. The processor may be a general-purpose CPU or a dedicated component such as an application specific integrated circuit ("ASIC") or other hardware-based processor. Although not required, specialized hardware components may be included to perform certain computational processes faster and more efficiently. For example, the operations of the present disclosure may be performed in parallel on a computer architecture having multiple cores with parallel processing capabilities. Each element in the figure may be singular or plural.

[0028] The instructions are described in more detail with respect to the flow diagram of FIG. 2. The system may further include one or more storage devices or memories 120 that store instructions 130 and programs executed by the one or more processors 110. In addition, the memory 120 may be configured to store data 140, such as one or more audio signals 142 and one or more reverberation effects 144 that may be applied to these audio signals. For example, the reverberation effects 144 may be selected to make the audio signals sound as if they were recorded in different acoustic spaces. Some reverberation effects may apply convolution, while other reverberation effects may work by identifying and synthesizing various vibration modes of a selected impulse response (IR).

[0029] The system 100 may further include an interface 150 for input and output of data. For example, an audio signal and a selected reverberation effect may be input to the system via the interface 150. In addition, as described in more detail below, modifications to the selected reverberation effect may also be input to the system via the interface 150. The system may also output the audio signal with the modified or unmodified reverberation effect applied via the interface 150. Other parameters and instructions may be provided to or from the system via the interface 150.

[0030] In some examples, system 100 may include a user's personal computer, laptop, tablet, or other computing device, within which both the processor and memory are housed. Operations performed by the system are described in more detail with respect to the routine of FIG.

[0031] FIG. 2 is a flow diagram illustrating an example routine 200 .

[0032] At block 210, the system may receive an audio signal. The audio signal may be a recorded audio file having one or more audio sources, such as musical instruments.

[0033] At block 220, the system may receive a selected modal reverberation effect to be applied to the audio signal. In some examples, the modal reverberation effect may include one or more vibration modes of a given acoustic space, such that applying the modal reverberation to the audio signal may cause the audio signal to sound as if it was recorded in the given acoustic space. Each vibration mode may be characterized by its respective properties, such as its shape and frequency. The frequency of a vibration mode may be the frequency at which the mode is centered or the frequency at which the maximum amount of energy of the mode is concentrated. The shape of the mode for each given frequency may define how the selected modal reverberation effect affects the portion of the audio signal located at the corresponding given frequency.

[0034] At block 230, the system may receive an input indicating one or more selected frequencies. The selected frequencies may correspond to the frequencies of several modes for which application of a reverberation effect to the audio signal may be desired to be individually controlled. For example, in the case of an audio signal including music from one or more instruments, the selected frequencies may be selected based on the tonality or scale of the music, notes that may be played on one or more instruments, other factors, or any combination thereof.

[0035] In block 240, the system can separate certain vibration modes of the selected modal reverberation effect into a first set and a second set. The first set can include vibration modes corresponding to modal frequencies included in the selected plurality of frequencies. The second set can include vibration modes corresponding to modal frequencies not included in the selected plurality of frequencies.

[0036] In block 250, the system can modify the selected modal reverberation effect by individually controlling the first and second sets of vibration modes. For example, the energy of the first set of vibration modes can be modified (e.g., increased, decreased) separately from the energy of the second set of vibration modes. As a result, a modified modal reverberation effect can be obtained that, when applied to an audio signal, can provide reverberation without causing disharmony in the reverberation effect between different audio sources contained in the audio signal. In block 260, the system can apply the modified modal reverberation effect to the audio signal.

[0037] In one example embodiment of the routine 200 of FIG. 2, the audio signal may be a recording of several instruments, and the selected frequencies may be preselected, so that no manual input is required. The preselected frequencies may correspond to the frequencies of notes included in a chromatic scale within a specified range (e.g., audio frequencies). In the recording, it may be expected that the instruments play primarily chromatic notes such that most of the energy in the audio signal from those instrument sources in the recording is concentrated around the frequencies of the chromatic notes. Therefore, it may also be expected that adding the energy of modal reverberation effects at those frequencies will cause overlaps that hinder the engineer's ability to equalize or balance the instruments in the audio signal. By isolating those frequencies, the modal reverberation effects can be emphasized at other frequencies, thus avoiding undesirable overlaps.

[0038] In another example, instead of selecting all frequencies that correspond to notes of a chromatic scale, a subset of frequencies can be selected or pre-selected, which may be preferable when the audio recording is in a known key or scale, or when it is known that the audio recording contains several instruments capable of reproducing a relatively limited number of notes.

[0039] For example, if an audio recording is known to be played in the key of C major, one can reasonably expect that reducing the energy of modal reverberation effects only in frequencies corresponding to notes of the tonality of C major will be sufficient to avoid undesirable overlaps. These concepts can be applied to other tonalities or scales such as the pentatonic scale.

[0040] As a further example, if the audio recording is known to include a particular instrument, the selected frequencies may correspond to center frequencies of notes produced by that instrument. By way of illustration, if the audio recording includes a piano, the notes may be the notes played by the keys of the piano.

[0041] In some examples, the selection of instrument notes and the selection of musical tonality or scale notes can be combined with each other. Taking the piano example again (although this example can be applied to any other musical instruments as well), the piano and other instruments in the audio recording may be playing a piece in a particular tonality or musical scale. Thus, the selected frequencies may correspond to particular notes in that tonality or scale, and to the center frequencies of the piano notes. In this way, both the tonality and the piano notes can be taken into account. For example, the selected frequencies may correspond to frequencies that are both piano notes and notes of a tonality or scale.

[0042] In any of the above examples, the energy at selected frequencies can be reduced to avoid reverberation at the selected notes causing disharmony between the instruments in the recording. However, due to the timbre of each instrument, the frequencies radiated by those instruments are not limited to the selected notes, so the reverberation will not be removed because energy will still be present at other frequencies surrounding the selected notes. As a result, the remaining energy can envelope or sweeten each instrument's note without disturbing the balance of the other instruments in the audio recording.

[0043] By way of example, it is expected that a similar effect can be produced for a guitar, in which case each string of the guitar can be used to play a number of notes defined by the frets on the guitar's fretboard. The number of selected frequencies can then correspond to all the center frequencies of notes that can be produced by the strings and frets. As with the piano or any other instrument, the number of selected frequencies can be further limited to the center frequencies of notes contained in a particular key or scale of a given recording. The energy at the selected frequencies can then be reduced to avoid the guitar's reverberation creating disharmony with other instruments in the recording. Due to the guitar's timbre, the frequencies radiated by the guitar are not limited to the selected notes, so the reverberation will not be eliminated, since there will still be energy at frequencies around the selected notes. As a result, the remaining energy can wrap or soften the guitar's notes without disturbing the balance of the other instruments.

[0044] On the other hand, guitars present another aspect of manipulating reverberation effects using the routines of the present disclosure. A user can adjust the frequency of a note on a guitar by bending the strings of the guitar while playing. This causes more energy to be concentrated in the vicinity of the frequencies surrounding the selected frequency, resulting in a sudden and abundant reverberation effect. Since the reverberation is not present at the selected frequency, it can be expected not to disturb the balance of other instruments in the recording.

[0045] The above example describes reducing the energy around a given frequency to avoid clashes between instruments, while in other examples the energy at the selected frequency can be increased, which can give the impression that the source of the note at the selected frequency is equally tempered, while suppressing the reverberation effects of the surrounding environment.

[0046] The above examples generally describe selecting a single set of frequencies and reducing or increasing the energy at those frequencies in isolation from other vibration modes included in the selected mode reverberation effect. The same concept can be used to divide the selected frequencies into individual sets and control those sets separately. In this regard, notes of a first instrument (e.g., piano) can be assigned to a first set and notes of a second instrument (e.g., guitar) can be assigned to a second set. In a similar regard, an audio recording may change tonality, whereby the frequencies of notes of the first tonality can correspond to the first set of selected frequencies and the frequencies of notes of the second tonality played subsequently can correspond to the second set of selected frequencies. The reverberation effect can then be adjusted for different portions of the audio recording depending on the instruments, tonalities, or any combination thereof playing in each portion of the recording.

[0047] In some examples, the selected frequencies may include not only those that correspond to the dominant frequencies of the notes of the instrument or audio recording, but also harmonics or dissonant frequencies of those dominant frequencies. Where the selected frequencies correspond to the dominant frequencies of the notes, the harmonics may correspond to octaves higher and lower than the notes. The same or similar principles may be applied to other frequencies, and may even be applied to any number of harmonics (second harmonic, third harmonic, etc.) or dissonant frequencies of a given dominant frequency.

[0048] In some examples, the selected frequencies may include frequencies that do not correspond to notes of a chromatic scale. In one such example, the audio recording may be played in a microtonal scale, whereby the selected frequencies may be frequencies that correspond to notes of the microtonal scale.

[0049] The routine of FIG. 2 can be applied manually, automatically, or a combination thereof. In the case of manual modification, a user can input a desired reverberation setting and a set of selected frequencies (which may correspond to a key, a scale, an instrument, or some combination thereof), and the reverberation signal can be modified based on the input information. In the case of automatic modification, one or more processors can analyze the audio recording or another audio recording to determine a particular note of the audio source. Such analysis can involve identifying the key or scale of the recording. In some cases, the analysis can involve determining the type of instrument being played in the recording. Furthermore, if the instrument, key, or scale of the recording changes during recording, the analysis can identify when the change occurred, and the audio recording can be separated into separate portions based on the main frequency in each portion, and different modifications can be applied to the reverberation effect for each of the separate portions. The system can further be capable of receiving manual modifications to the automated decisions to provide a combination of both manual and automatic input.

[0050] For example, if an audio recording includes a first instrument (e.g., piano) and a second instrument (e.g., guitar), the recording can be analyzed to identify the frequencies of the notes of the first instrument and to de-emphasize the reverberation effect of those frequencies. This can have the effect of emphasizing the reverberation effect of the frequencies of the notes of the second instrument that are different from the frequencies of the notes of the first instrument. Similarly, those skilled in the art will recognize that multiple audio recordings can be combined to create a combined audio recording. Thus, controlling the reverberation effect of one recording based on the frequency of another recording can be useful, for example, when it is expected or desired to combine the two recordings together.

[0051] The above example generally describes the application of the routine of FIG. 2 to a modal reverberation effect. Using modal reverberation is particularly useful since the modal reverberation is composed of several vibration modes of a simulated or real acoustic space, and the selected frequencies can correspond to the frequencies of a select group of vibration modes. However, similar principles can be used to modify convolutional reverberation. For example, a Fast Fourier Transform (FFT) can be applied to the impulse response of the simulated space to represent the impulse response of the space in the frequency domain. The energy at specific frequencies of the frequency domain representation of the impulse response can then be increased or decreased in the same or similar manner as described above to derive a modified impulse response. The modified impulse response can then be applied to an audio recording using convolutional reverberation, thus resulting in a modified reverberation effect.

[0052] Overall, the present disclosure may enable a user to more effectively manipulate the reverberation effect of an audio recording that includes multiple audio sources without interfering with the user's ability to balance the audio sources. A user may start with an audio recording of several instruments, manually or automatically identify the notes played in the recording, and isolate the vibration modes of those notes from other vibration modes in a selected modal reverberation effect. The modal reverberation may then be accentuated or muted according to the user's preferences at the particular identified notes, resulting in a different sound in the audio recording.

[0053] Although the invention has been described herein with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications can be made to the illustrative embodiments and other arrangements can be devised without departing from the spirit and scope of the invention as defined by the appended claims. In order to maintain the disclosure matters at the time of filing of the present application, the contents of claims 1 to 26 at the time of filing of the present application are added as follows. (Claim 1) receiving an audio signal; receiving a modal reverberation effect to be applied to the audio signal, the modal reverberation effect comprising one or more vibration modes of a given acoustic space, each vibration mode having a corresponding modal frequency; determining a number of frequencies that modify the modal reverberation effect; generating a first set and a second set of vibration modes from the one or more vibration modes of the modal reverberation effect, each vibration mode in the first set having a modal frequency corresponding to one of the plurality of frequencies and each vibration mode in the second set having a modal frequency not corresponding to any of the plurality of frequencies; modifying the modal reverberation effect by adjusting the first set of vibration modes of the modal reverberation effect in isolation from the second set of vibration modes of the modal reverberation effect; applying the modified modal reverberation effect to the audio signal; A method executed by one or more processors, comprising: (Claim 2) The method of claim 1 , wherein the plurality of frequencies corresponds to the frequencies of notes of a chromatic scale within a specified range. (Claim 3) The method of claim 1 , wherein the plurality of frequencies includes two or more frequencies corresponding to notes of a microtonal scale. (Claim 4) The method of claim 1 , wherein the plurality of frequencies corresponds to a subset of the frequencies of notes of a chromatic scale. (Claim 5) 5. The method of claim 4, wherein determining a plurality of frequencies for modifying the modal reverberation effect includes receiving, by the one or more processors, an input indicative of a musical tonality or a musical scale, each of the plurality of frequencies corresponding to a frequency of a note included in the musical tonality or the musical scale. (Claim 6) 5. The method of claim 4, wherein determining a plurality of frequencies for modifying the modal reverberation effect includes receiving, by the one or more processors, an input indicative of one or more musical instruments, the plurality of frequencies being associated with the one or more musical instruments. (Claim 7) 7. The method of claim 6, wherein the one or more musical instruments include a piano having a plurality of keys, each key corresponding to a frequency, and the plurality of frequencies includes the corresponding frequencies of the keys. (Claim 8) 7. The method of claim 6, wherein the one or more musical instruments include a guitar having a plurality of strings, each string having a plurality of frets, each fret of each string corresponding to a frequency, and the plurality of frequencies includes the corresponding frequencies of the frets. (Claim 9) The method of claim 1 , wherein the multiple frequencies include one or more fundamental frequencies and harmonics of the fundamental frequency. (Claim 10) The method of claim 1 , wherein adjusting the first set of modes comprises adjusting a mode shape of each mode included in the first set of modes. (Claim 11) 8. The method of claim 7, wherein adjusting the first set of modes includes reducing, by the one or more processors, an energy of each mode included in the first set of modes. (Claim 12) 8. The method of claim 7, wherein adjusting the first set of vibrational modes includes increasing, by the one or more processors, an energy of each mode in the first set of modes. (Claim 13) The method of claim 1 , wherein determining a plurality of frequencies that modify the modal reverberation effect comprises deriving, by the one or more processors, the plurality of frequencies from an analysis of the audio signal. (Claim 14) one or more processing devices; a memory storing one or more programs configured to be executed by the one or more processing devices; A system comprising: The one or more programs include Receiving an audio signal; receiving a modal reverberation effect to be applied to the audio signal, the modal reverberation effect including one or more vibration modes of a given acoustic space, each vibration mode having a corresponding modal frequency; determining a plurality of frequencies that modify the modal reverberation effect; generating a first set and a second set of vibration modes from the one or more vibration modes of the modal reverberation effect, each vibration mode in the first set having a modal frequency corresponding to one of the plurality of frequencies, and each vibration mode in the second set having a modal frequency not corresponding to any of the plurality of frequencies; modifying the modal reverberation effect by adjusting the first set of vibration modes of the modal reverberation effect separately from the second set of vibration modes of the modal reverberation effect; applying the modified modal reverberation effect to the audio signal; and and instructions for execution by the one or more processing devices. (Claim 15) 15. The system of claim 14, wherein the plurality of frequencies correspond to the frequencies of notes of a chromatic scale within a specified range. (Claim 16) 15. The system of claim 14, wherein the plurality of frequencies includes two or more frequencies corresponding to notes of a microtonal scale. (Claim 17) 15. The system of claim 14, wherein the plurality of frequencies corresponds to a subset of the frequencies of notes of a chromatic scale. (Claim 18) 20. The system of claim 17, wherein the one or more processing devices are configured to receive an input indicative of a musical key or a musical scale, and each of the plurality of frequencies corresponds to a frequency of a note included in the musical key or musical scale. (Claim 19) 20. The system of claim 17, wherein the one or more processing devices are configured to receive input indicative of one or more musical instruments, and the multiple frequencies are associated with the one or more musical instruments. (Claim 20) 20. The system of claim 19, wherein the one or more musical instruments include a piano having a plurality of keys, each key corresponding to a frequency, and the plurality of frequencies includes the corresponding frequencies of the keys. (Claim 21) 20. The system of claim 19, wherein the one or more musical instruments include a guitar having a plurality of strings, each string having a plurality of frets, each fret of each string corresponding to a frequency, and the plurality of frequencies includes the corresponding frequencies of the frets. (Claim 22) 15. The system of claim 14, wherein the multiple frequencies include one or more fundamental frequencies and harmonics of the fundamental frequency. (Claim 23) 15. The system of claim 14, wherein the one or more processing devices are configured to adjust a mode shape of each mode in the first set of modes. (Claim 24) 24. The system of claim 23, wherein the one or more processing devices are configured to adjust the vibration modes of the modal reverberation effect by adjusting the mode shapes to reduce energy of each mode included in the first set of modes. (Claim 25) 24. The system of claim 23, wherein the one or more processing devices are configured to adjust the vibration modes of the modal reverberation effect by adjusting the mode shapes to increase energy of each mode in the first set of modes. (Claim 26) The one or more processing devices analyzing the audio signal; determining at least one of a tonality, a scale, or an instrument of the audio signal based on said analysis;

[0023] 15. The system of claim 14, wherein the determined frequencies for modifying the modal reverberation effect correspond to the determined tonal, musical scale, or instrumental frequencies.

Claims

1. receiving an audio signal; receiving a modal reverberation effect to be applied to the audio signal, the modal reverberation effect comprising one or more vibration modes of a given acoustic space, each vibration mode having a corresponding modal frequency; determining a number of frequencies that modify the modal reverberation effect; generating a first set and a second set of vibration modes from the one or more vibration modes of the modal reverberation effect, each vibration mode in the first set having a modal frequency corresponding to one of the plurality of frequencies, and each vibration mode in the second set having a modal frequency not corresponding to any of the plurality of frequencies; modifying the modal reverberation effect by adjusting a first set of vibration modes of the modal reverberation effect in isolation from a second set of vibration modes of the modal reverberation effect; applying the modified modal reverberation effect to the audio signal; comprising The plurality of frequencies are said frequencies of chromatic notes within a specified range; two or more frequencies corresponding to notes of a microtonal scale; a subset of said frequencies of chromatic notes; one or more fundamental frequencies and harmonics of the fundamental frequencies; A method executed by one or more processors, the method corresponding to at least one of:

2. The method of claim 1 , wherein the plurality of frequencies corresponds to the frequencies of notes of a chromatic scale within a specified range.

3. The method of claim 1 , wherein the plurality of frequencies includes two or more frequencies corresponding to notes of a microtonal scale.

4. The method of claim 1 , wherein the plurality of frequencies corresponds to a subset of the frequencies of notes of a chromatic scale.

5. 5. The method of claim 4, wherein determining a plurality of frequencies for modifying the modal reverberation effect comprises receiving, by the one or more processors, an input indicative of a musical tonality or a musical scale, each of the plurality of frequencies corresponding to a frequency of a note included in the musical tonality or the musical scale.

6. 5. The method of claim 4, wherein determining a plurality of frequencies for modifying the modal reverberation effect comprises receiving, by the one or more processors, input indicative of one or more musical instruments, the plurality of frequencies being associated with the one or more musical instruments.

7. The method of claim 6 , wherein the one or more musical instruments include a piano having a plurality of keys, each key corresponding to a frequency, and the plurality of frequencies includes the corresponding frequencies of the keys.

8. 7. The method of claim 6, wherein the one or more musical instruments include a guitar having a plurality of strings, each string having a plurality of frets, each fret of each string corresponding to a frequency, and the plurality of frequencies includes the corresponding frequencies of the frets.

9. The method of claim 1 , wherein the multiple frequencies include one or more fundamental frequencies and harmonics of the fundamental frequency.

10. The method of claim 1 , wherein adjusting the first set of modes comprises adjusting a mode shape of each mode included in the first set of modes.

11. The method of claim 7 , wherein adjusting the first set of modes comprises reducing, by the one or more processors, an energy of each mode included in the first set of modes.

12. The method of claim 7 , wherein adjusting the first set of vibrational modes includes increasing, by the one or more processors, an energy of each mode in the first set of modes.

13. The method of claim 1 , wherein determining a plurality of frequencies that modify the modal reverberation effect comprises deriving, by the one or more processors, the plurality of frequencies from an analysis of the audio signal.

14. one or more processing devices; a memory storing one or more programs configured to be executed by the one or more processing devices; A system comprising: The one or more programs are Receiving an audio signal; receiving a modal reverberation effect to be applied to the audio signal, the modal reverberation effect including one or more vibration modes of a given acoustic space, each vibration mode having a corresponding modal frequency; determining a plurality of frequencies for modifying the modal reverberation effect, the plurality of frequencies comprising: said frequencies of chromatic notes within a specified range; two or more frequencies corresponding to notes of a microtonal scale; a subset of said frequencies of chromatic notes; one or more fundamental frequencies and harmonics of the fundamental frequencies; and generating a first set and a second set of vibration modes from the one or more vibration modes of the modal reverberation effect, each vibration mode in the first set having a modal frequency corresponding to one of the plurality of frequencies, and each vibration mode in the second set having a modal frequency not corresponding to any of the plurality of frequencies; modifying the modal reverberation effect by adjusting a first set of vibration modes of the modal reverberation effect in isolation from a second set of vibration modes of the modal reverberation effect; applying the modified modal reverberation effect to the audio signal; and and instructions for execution by the one or more processing devices.

15. The system of claim 14 , wherein the plurality of frequencies correspond to the frequencies of notes of a chromatic scale within a specified range.

16. The system of claim 14 , wherein the plurality of frequencies includes two or more frequencies corresponding to notes of a microtonal scale.

17. The system of claim 14 , wherein the plurality of frequencies corresponds to a subset of the frequencies of notes of a chromatic scale.

18. 20. The system of claim 17, wherein the one or more processing devices are configured to receive an input indicative of a musical key or a musical scale, and each of the plurality of frequencies corresponds to a frequency of a note included in the musical key or musical scale.

19. 20. The system of claim 17, wherein the one or more processing devices are configured to receive input indicative of one or more musical instruments, and the multiple frequencies are associated with the one or more musical instruments.

20. 20. The system of claim 19, wherein the one or more musical instruments include a piano having a plurality of keys, each key corresponding to a frequency, and the plurality of frequencies includes the corresponding frequencies of the keys.

21. 20. The system of claim 19, wherein the one or more musical instruments include a guitar having multiple strings, each string having multiple frets, each fret of each string corresponding to a frequency, and the multiple frequencies include the corresponding frequencies of the frets.

22. The system of claim 14 , wherein the multiple frequencies include one or more fundamental frequencies and harmonics of the fundamental frequency.

23. The system of claim 14 , wherein the one or more processing devices are configured to adjust a mode shape of each mode in the first set of modes.

24. 24. The system of claim 23, wherein the one or more processing devices are configured to adjust the vibration modes of the modal reverberation effect by adjusting the mode shapes to reduce energy of each mode in the first set of modes.

25. 24. The system of claim 23, wherein the one or more processing devices are configured to adjust the vibration modes of the modal reverberation effect by adjusting the mode shapes to increase energy of each mode in the first set of modes.

26. The one or more processing devices analyzing the audio signal; determining at least one of a tonality, a scale, or an instrument of the audio signal based on said analysis; [0023] 15. The system of claim 14, wherein the determined frequencies for modifying the modal reverberation effect correspond to the determined tonal, musical scale, or instrumental frequencies.

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