Modal reverberation effects of an acoustic space

Abstract

Methods and systems for a method of modifying a reverb technique for audio signals are described. The method can include receiving an audio signal, a modal reverb effect to be applied to the audio signal, and an indication of a plurality of frequencies. Spatial vibration modes simulated by the reverb effect can be separated into a set of frequencies included in the input and a set of frequencies not included in the input. The modal reverb effect can be modified by individually adjusting individual sets of vibration modes. The modified effect can then be applied to the audio signal.

Description

[0001] Cross-reference to related applications

[0002] This application is a continuation of U.S. Patent Application No. 16 / 585036, filed on September 27, 2019, the disclosure of which is incorporated herein by reference. Background Technology

[0003] Audio engineers, musicians, and even the general public (collectively referred to as "users") are all accustomed to generating and processing audio signals. For example, audio engineers edit stereo signals by mixing mono audio signals together using effects such as shifting and gaining, thereby positioning them within a stereo field. Users can also process audio signals as separate components for effects processing using multi-band structures such as crossover networks, achieving multi-band processing. Furthermore, musicians and audio engineers frequently use audio effects such as compression, distortion, delay, and reverb to produce pleasing sounds, and sometimes even unpleasant ones. Audio signal processing is typically performed using specialized software or hardware. The type of hardware and software used to manipulate audio signals usually depends on the user's intent. Users are constantly seeking new methods to create and process audio signals.

[0004] Reverb is one of the most common effects that users apply to audio signals. Reverb effects simulate the reverberation of a specific room or acoustic space, making the audio signal sound as if it was recorded in a room with a specific impulse response.

[0005] One way to apply reverberation to audio signals is by using a technique called convolution. Convolutional reverberation applies the impulse response of a given acoustic space to an audio signal, causing the audio signal to sound as if it were generated in that given space. However, the techniques for controlling convolutional reverberation parameters are relatively limited. For example, using convolutional reverberation, it may be impossible to isolate and manipulate the resonance of individual frequencies in the audio signal. Furthermore, using convolutional reverberation may also make it impossible to adjust or manipulate single properties of the simulated physical space (e.g., the length or width of the space).

[0006] Another method for applying reverberation to audio signals is to use a technique called modal reverberation. Unlike convolutional reverberation, modal reverberation analyzes the impulse response of a given space, determines the vibrational modes in that space based on the analysis, and then synthesizes the individual vibrational modes in the space. Therefore, the individual frequencies of the reverberation can be isolated and edited, and the techniques used to manipulate modal reverberation parameters are more robust than those used to manipulate convolutional reverberation parameters.

[0007] One challenge in audio production arises when multiple instruments are playing simultaneously with reverb in an audio signal. Reverb can be a property of the recording setup or it can be added by the audio engineer. In either case, especially when multiple sources in the audio signal have reverb, balancing these different sources can be difficult.

[0008] Currently available audio signal processing and equalization products allow users to equalize input or output signals. In some cases, the impulse response applied to an audio signal can be equalized. However, in all these cases, overlap between multiple sources hinders the ability of known equalizers to balance the sources. Summary of the Invention

[0009] This technology relates to systems for controlling the characteristics of reverberation effects applied to audio signals. It also relates to managing such systems to improve the generated signal, and optionally, software applications that interact with the user to give the user more control over the reverberation effect and the generated signal. This can improve known reverberation techniques by individually controlling specific frequencies of the reverberation from one or more sources of a known audio signal. In some cases, when a reverberation effect is applied, the energy of the audio signal at these 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 to give the impression of a favorable source, the energy at specific frequencies can be selectively enhanced. Other example effects are described in this document.

[0010] This technology can be implemented on a server or electronic device communicating with an application on an electronic device in the form of software or machine instructions on a computer or computer network. The computer or computer network may include one or more processors and memory storing one or more programs configured to be executed by the one or more processors. The memory may also store data used during the execution of the one or more programs. In operation, one or more programs can receive audio signals and input from a user and can adjust the characteristics of reverberation effects applied to the audio signals based on user input.

[0011] When applying modal reverberation effects to an audio signal, the effect is generated by calculating the individual vibration modes of the acoustic space through analysis of the impulse response. Each vibration mode can include a modal frequency and a modal shape. One or more programs can then adjust the modal shape of a specific vibration mode corresponding to a frequency indicated by user input. Adjusting the modal shape may involve reducing or increasing the energy of a specific vibration mode in the modal reverberation effect, depending on the desired effect. The modified modal reverberation effect can then be applied to the audio signal.

[0012] A similar concept can be used to modify convolutional reverberation effects applied to audio signals. In the case of convolutional reverberation effects, a Fast Fourier Transform (FFT) can be used to transform the impulse response of the acoustic space to represent the acoustic space in the frequency domain. Then, portions of the frequency domain signal corresponding to one or more frequencies input by the user can be adjusted.

[0013] User input may include one or more frequencies. These frequencies may correspond to the frequencies of a set of notes played in the recording. The set of notes may be the pitch, scale, or one or more instruments played in the recording. In some cases, one or more frequencies may include harmonics of the notes (e.g., second harmonics, etc.) as well as the non-harmonic frequencies of the notes.

[0014] In operation, this system can be used to achieve reverberation effects on audio signals without adding energy that clashes with certain instruments in the audio signal. For example, if a user wants to apply a reverberation effect to an audio recording of a piano (and other instruments and / or sounds) being played, the user can provide the system with the audio recording, select the desired reverberation effect, and further select "piano" as the 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 around the specific frequencies input by the user to avoid interfering with the sounds of other instruments in the recording. This achieves a reverberation effect applied to the recording, but in a way that surrounds and enhances the piano sound without clashing with other instruments.

[0015] In another example, instead of selecting a specific instrument, the user can choose a key, such as C major. In this case, the energy of the selected reverb effect can decay at or around the frequencies associated with C major, while the energy of the reverb effect at the remaining frequencies can be maintained.

[0016] In other examples, instead of attenuating the energy of a selected reverb effect at a specific frequency, the energy can be amplified at a specific frequency to produce a well-harmonious instrumental or acoustic space effect.

[0017] One aspect of the present invention 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 comprising 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, including 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 one of the plurality of frequencies; adjusting to modify the modal reverberation effect by separating the first set of vibration modes of the modal reverberation effect from the second set of vibration modes of the modal reverberation effect; and applying the modified modal reverberation effect to the audio signal.

[0018] In some examples, multiple frequencies may correspond to the frequencies of chromatic notes within a specified range. In some examples, multiple frequencies may include two or more frequencies corresponding to notes in a microtone. In some examples, multiple frequencies may correspond to a subset of the frequencies of chromatic notes. Determining multiple frequencies for modifying a modal reverberation effect may include receiving input from one or more processors indicating a pitch or scale, each of the multiple frequencies corresponding to the frequency of a note included in that pitch or scale. Alternatively or additionally, determining multiple frequencies for modifying a modal reverberation effect may include receiving input from one or more processors indicating one or more instruments, the multiple frequencies being associated with one or more instruments. One or more instruments may include any one or a combination of: a piano with multiple keys, each key corresponding to a frequency, the multiple frequencies including the corresponding frequencies of the multiple keys; and a guitar with 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 multiple frets.

[0019] In some examples, the multiple frequencies may include one or more fundamental frequencies, as well as harmonics of the fundamental frequencies. In some examples, adjusting the first set of modes may include adjusting the modal shape of each mode included in the first set of modes, for example, by reducing the energy of each mode included in the first set of modes by one or more processors, or by increasing the energy of each mode included in the first set of modes by one or more processors.

[0020] In some examples, determining multiple frequencies used to modify the modal reverberation effect may include deriving multiple frequencies from the analysis of the audio signal by one or more processors.

[0021] Another aspect of the invention 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 may include instructions for execution by the one or more processing devices: 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 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, including 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 one of the plurality of frequencies; adjusting to modify the modal reverberation effect by separating the first set of vibration modes of the modal reverberation effect from the second set of vibration modes of the modal reverberation effect; and applying the modified modal reverberation effect to the audio signal.

[0022] In some examples, multiple frequencies may correspond to the frequencies of chromatic notes within a specified range. In some examples, multiple frequencies may include two or more frequencies corresponding to notes in a microtone. Multiple frequencies may correspond to a subset of the frequencies of chromatic notes. One or more processing devices may be configured to receive input indicating a tone or scale, each of the multiple frequencies corresponding to the frequency of a note included in that tone or scale. Alternatively or additionally, one or more processing devices may be configured to receive input indicating one or more musical instruments, wherein the multiple frequencies are associated with one or more musical instruments. One or more musical instruments may include any one or a combination of: a piano with multiple keys, each key corresponding to a frequency, the multiple frequencies including the corresponding frequencies of the multiple keys; and a guitar with 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 multiple frets.

[0023] In some examples, multiple frequencies may include one or more fundamental frequencies, as well as harmonics of the fundamental frequencies.

[0024] In some examples, one or more processing devices may be configured to adjust the modal shape of each mode included in the first set of modes, for example, by adjusting the modal shape to reduce the energy of each mode included in the first set of modes, or by adjusting the modal shape to increase the energy of each mode included in the first set of modes.

[0025] In some examples, one or more processing devices may be configured to analyze an audio signal and, based on the analysis, determine at least one of the pitch, scale, or instrument of the audio signal. The determined frequencies used to modify the modal reverberation effect may correspond to the frequencies of the determined pitch, scale, or instrument. Attached Figure Description

[0026] The foregoing aspects, features, and advantages of the invention will be further understood when considered with reference to the following description and accompanying drawings of exemplary embodiments, wherein like reference numerals denote like elements. Specific terminology may be used for clarity in describing embodiments of the invention illustrated in the drawings. However, aspects of the invention are not intended to be limited to the specific terminology used.

[0027] Figure 1 This is a block diagram of an example system according to one aspect of the present invention.

[0028] Figure 2 This is a flowchart of an example method according to one aspect of the present invention. Detailed Implementation

[0029] Figure 1 An example system 100 for performing the modal reverberation techniques described in this application is illustrated. System 100 may include one or more processing devices 110 configured to execute a set of instructions or an executable program. The processor may be a dedicated component such as a general-purpose CPU or an application-specific integrated circuit (“ASIC”), or it may be other hardware-based processors. Although not required, specialized hardware components may be included to perform specific computational processes faster or more efficiently. For example, the operations of the present invention can be performed in parallel on a computer architecture having multiple cores with parallel processing capabilities.

[0030] Combination Figure 2 The flowchart describes the illustration in more detail. The system may also include one or more storage devices or memories 120 for storing instructions 130 and programs executed by one or more processors 110. Furthermore, 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 can be applied to the audio signals. For example, reverberation effects 144 can be selected to make the audio signal sound as if it were recorded in different acoustic spaces. Some reverberation effects may apply convolution, while others may work by identifying and synthesizing various vibrational modes and selected impulse responses (IR).

[0031] System 100 may also include an interface 150 for data input and output. For example, an audio signal and a selected reverb effect may be input to the system via interface 150. Furthermore, as described in more detail below, modifications to the selected reverb effect may also be input to the system via interface 150. The system may also output an audio signal with or without the applied modified reverb effect via interface 150. Other parameters and commands may be provided to or from the system via interface 150.

[0032] In some examples, system 100 may include a personal computer, laptop, tablet, or other computing device belonging to the user, which includes a processor and memory. Figure 2 The routines describe the operations performed by the system in more detail.

[0033] Figure 2 This is a flowchart illustrating example routine 200.

[0034] In box 210, the system can receive audio signals. The audio signal may be a recorded audio file with one or more audio sources (such as musical instruments).

[0035] In box 220, the system may receive a selected modal reverberation effect to be applied to an audio signal. In some examples, the modal reverberation effect may include one or more vibrational modes of a given acoustic space, thereby making the audio signal sound as if it were recorded in the given acoustic space. Each vibrational mode may be characterized by its own properties, such as its shape and frequency. The frequency of the vibrational mode may be the center frequency of the mode or the frequency at which the mode's maximum energy is concentrated. The shape of the mode at each given frequency may indicate how the selected modal reverberation effect affects the portion of the audio signal located at the corresponding given frequency.

[0036] In box 230, the system may receive input indicating one or more selected frequencies. The selected frequencies may correspond to frequencies of certain patterns for which the application of reverberation effects to the audio signal may need to be controlled individually. For example, in the case of an audio signal containing music from one or more instruments, the selected frequencies may be chosen based on the pitch or scale of the music, notes that can be played on one or more instruments, other factors, or any combination thereof.

[0037] In box 240, the system can separate specific vibration modes of a selected modal reverberation effect into a first group and a second group. The first group may include those vibration modes corresponding to modal frequencies included in the selected plurality of frequencies. The second group may include those vibration modes corresponding to modal frequencies not included in the plurality of selected frequencies.

[0038] In box 250, the system can modify the selected modal reverberation effect by controlling the first and second sets of vibration modes separately. For example, the energy of the first set of vibration modes can be modified separately from the energy of the second set of vibration modes (e.g., increased or decreased). The result can be a modified modal reverberation effect that, when applied to an audio signal, can generate reverberation between different sources included in the audio signal without conflict. In box 260, the system can apply the modified modal reverberation effect to the audio signal.

[0039] exist Figure 2In one example embodiment of routine 200, the audio signal may be a recording of multiple instruments, and multiple selected frequencies may be pre-selected, thus eliminating the need for manual input. The pre-selected frequencies may correspond to note frequencies (e.g., audible frequencies) included in a specified range of chromatic frequencies. In a recording, one might expect the instruments to primarily play chromatic notes, so much of the energy in the audio signal from these instrument sources in the recording will be concentrated around the frequencies of the chromatic notes. Therefore, one might also expect to add energy to modal reverberation effects at these frequencies to cause overlap, thereby interfering with the engineer's ability to equalize or balance the instruments in the audio signal. By separating these frequencies, modal reverberation effects can be emphasized at other frequencies, thus avoiding unnecessary overlap.

[0040] In another example, instead of selecting all frequencies corresponding to chromatic notes, a subset of frequencies can be selected or pre-selected. This may be preferred if the audio recording uses a known tone or scale, or if the audio recording is known to include certain instruments capable of playing a relatively limited number of notes.

[0041] For example, if an audio recording is known to be played in C major, it is reasonable to expect that reducing the energy of the modal reverberation effect only at the frequencies corresponding to C major notes would be sufficient to avoid unnecessary overlap. A similar concept can be applied to other keys or scales, such as the pentatonic scale.

[0042] For example, if an audio recording is known to include a specific instrument, then several selected frequencies may correspond to the center frequencies of the notes produced by that instrument. For instance, if the recording includes a piano, then these notes might be the notes played on the piano keys.

[0043] In some examples, the selection of musical notes and the notes of a tone or scale can be combined with each other. Again, using the piano as an example (although this example can be applied to any other instrument), a recording of a piano and other instruments may be playing a piece in a specific tone or scale. Therefore, multiple selected frequencies can correspond to the center frequency of a specific note included in the tone or scale, as well as the piano note itself. In this way, both the piano tone and the note can be considered simultaneously. For example, a selected frequency could correspond to a frequency that is both a piano note and a tone or scale note.

[0044] In any of the examples above, the energy at a selected frequency might be reduced to prevent reverberation at the selected note from clashing between instruments in the recording. However, due to the timbre of each instrument, the frequencies emitted by the instrument are not limited to the selected note, so the reverberation is not eliminated because there is still energy at other frequencies around the selected note. Therefore, the remaining energy may mask or enhance the tone of each instrument without interfering with the balance of other instruments in the audio recording.

[0045] For example, one might expect to produce a similar effect for a guitar. In the case of a guitar, each string can be used to play multiple notes indicated by the frets on the fretboard. These multiple selected frequencies can then correspond to the center frequencies of all the notes that can be produced by the strings and frets. As with a piano or any other instrument, these selected frequencies can be further limited to the center frequencies of notes included in a specific key or scale within a given recording. The energy of these selected frequencies can then be reduced to avoid the guitar reverberation clashing with other instruments in the recording. Because of the guitar's timbre, the frequencies it emits are not limited to the selected notes, so the reverberation is not eliminated because the frequencies around the selected notes still have energy. As a result, the remaining energy can mask or enhance the guitar's notes without interfering with the balance of other instruments.

[0046] However, the guitar offers an additional aspect for manipulating reverb effects using the routines of this invention. Users can adjust the frequency of notes on the guitar by bending the strings while playing. This causes more energy to concentrate on frequencies around the selected frequency, which in turn causes a sudden burst of reverb. Because the reverb is not at the selected frequency, one might assume it won't interfere with the balance of other instruments in the recording.

[0047] The example above describes reducing energy near a given frequency to avoid conflict between instruments. However, in other examples, energy at a selected frequency can be increased. This might give the impression that the note source at the selected frequency is well tuned, while the reverberation of the surrounding environment might be reduced.

[0048] The examples above typically describe selecting a single group of frequencies and then individually decreasing or increasing the energy at those frequencies, along with other vibrational modes included in the selected modal reverberation effect. The same concept can be used to divide selected frequencies into separate sets and control these sets individually. In this respect, notes from a first instrument (e.g., a piano) can be designated as the first group, and notes from a second instrument (e.g., a guitar) can be designated as the second group. Similarly, an audio recording can change the pitch, so that the frequencies of notes in a first pitch can correspond to the selected frequencies in the first group, and the frequencies of notes in a subsequently played second pitch can correspond to the selected frequencies in the second group. The reverberation effect can then be adjusted for different parts of the recording based on the instrument, pitch, or any combination thereof played in each part of the recording.

[0049] In some examples, the selected frequencies may include not only the frequencies corresponding to the tonic frequencies of the notes on the instrument or audio recording, but also the harmonics or aharmonics of those tonic frequencies. Where the selected frequency corresponds to the tonic frequency of the note, the harmonics may correspond to the octave above and below the note. The same or similar principles can be applied to other frequencies, and further to any number of harmonics (second harmonic, third harmonic, etc.) or aharmonics of a given tonic frequency.

[0050] In some examples, the selected frequencies may include frequencies that do not correspond to chromatic notes. In one such example, the audio recording may be played in microtones, where the selected frequencies could be frequencies that correspond to microtone notes.

[0051] Figure 2 The routines can be applied manually, automatically, or in combination. In the case of manual modification, the user can input the desired reverb settings and a selected set of frequencies (potentially corresponding to pitch, scale, instrument, or some combination thereof), and can modify the reverb signal based on the input information. In the case of automatic modification, one or more processors can analyze an audio recording or another audio recording to determine specific notes of the source. This analysis may include determining the pitch or scale of the recording. In some cases, the analysis may include determining the type of instrument played in the recording. Furthermore, if the instrument, pitch, or scale of the recording changes during recording, the analysis can identify the time of the change, can separate the audio recording into individual sections based on the dominant frequency in each section, and can apply different modifications to the reverb effect of each individual section. The system is also capable of receiving manual modifications to automatically determined parameters to provide a combination of manual and automatic input.

[0052] For example, if an audio recording includes each of a first instrument (e.g., a piano) and a second instrument (e.g., a guitar), the recording can be analyzed to identify the frequencies of the notes from the first instrument and to reduce the reverberation at those frequencies. This, in turn, can have a reverberation effect that enhances the frequencies of the notes from the second instrument, which are different from the first instrument. Similarly, those skilled in the art will recognize that multiple audio recordings can be combined to produce a combined audio recording. Therefore, controlling the reverberation of a recording based on the frequencies of another recording can be useful, for example, if it is desired or desired to combine two recordings with each other.

[0053] The above examples typically describe... Figure 2The routines described above are applied to modal reverberation effects. Modal reverberation is particularly advantageous because it consists of multiple vibrational modes of a simulated or real acoustic space, and selected frequencies can correspond to the frequencies of a selected group of vibrational 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 a simulated space to represent the impulse response in the frequency domain. The energy at specific frequencies in the frequency domain representation of the impulse response can then be increased or decreased in the same or similar manner to derive a modified impulse response. This modified impulse response can then be applied to an audio recording using convolutional reverberation to produce a modified reverberation effect.

[0054] In summary, this invention enables users to more effectively manipulate the reverberation effects of audio recordings containing multiple sound sources without compromising their ability to balance the sound sources. Users can begin with audio recordings of multiple instruments, manually or automatically identify the notes played in the recording, and separate the vibrational modes of these notes from other vibrational modes within a selected modal reverberation effect. Then, according to the user's preference, the modal reverberation can be emphasized or muted at specific identified notes, thereby producing a sound different from the audio recording.

[0055] Although the invention described herein has been illustrated with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. Therefore, it should be understood that many 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 in the appended claims.

Claims

1. A method performed by one or more processors, the method comprising: including: receiving an audio signal; receiving a modal reverb effect to be applied to the audio signal, the modal reverb effect comprising one or more modes of vibration of a given acoustic space, each mode of vibration having a corresponding modal frequency; determining a plurality of frequencies for modifying the modal reverb effect; generating a first set and a second set of modes of vibration from the one or more modes of vibration of the modal reverb effect, wherein each mode of vibration included in the first set has a modal frequency corresponding to one of the plurality of frequencies, and wherein each mode of vibration included in the second set has a modal frequency that does not correspond to any of the plurality of frequencies; adjusting to modify the modal reverb effect by separating the first set of modes of vibration of the modal reverb effect from the second set of modes of vibration of the modal reverb effect, wherein adjusting the first set of modes includes adjusting a modal shape of each mode in the first set of modes; and applying the modified modal reverb effect to the audio signal.

2. The method of claim 1, wherein, The plurality of frequencies corresponds to frequencies of semitone scale notes 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 frequencies of semitone scale notes.

5. The method of claim 4, wherein, Determining the plurality of frequencies for modifying the modal reverb effect includes receiving, by the one or more processors, input indicative of a key or scale, wherein each of the plurality of frequencies corresponds to a frequency of a note included in the key or scale.

6. The method of claim 4, wherein, Determining the plurality of frequencies for modifying the modal reverb effect includes receiving, by the one or more processors, input indicative of one or more musical instruments, wherein the plurality of frequencies are 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 wherein the plurality of frequencies include the corresponding frequencies of the plurality of keys.

8. 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 wherein the plurality of frequencies include the corresponding frequencies of the plurality of frets.

9. The method of claim 1, wherein, The plurality of frequencies includes one or more fundamental frequencies and harmonics of the fundamental frequencies.

10. 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.

11. The method of claim 7, wherein, Adjusting the first set of modes of vibration includes increasing, by the one or more processors, an energy of each mode including the first set of modes.

12. The method of claim 1, wherein, Determining the plurality of frequencies for modifying the modal reverb effect includes deriving, by the one or more processors, the plurality of frequencies from an analysis of the audio signal.

13. A system, characterized by including: one or more processing devices; and memory storing one or more programs configured to be executed by the one or more processing devices, the one or more programs comprising instructions for execution by the one or more processing devices: receiving an audio signal; receiving a modal reverb effect to be applied to the audio signal, the modal reverb effect comprising one or more modes of vibration of a given acoustic space, each mode of vibration having a corresponding modal frequency; determining a plurality of frequencies for modifying the modal reverb effect; generating a first set and a second set of modes of vibration from the one or more modes of vibration of the modal reverb effect, wherein each mode of vibration included in the first set has a modal frequency corresponding to one of the plurality of frequencies, and wherein each mode of vibration included in the second set has a modal frequency that does not correspond to any of the plurality of frequencies; adjusting to modify the modal reverb effect by separating the first set of modes of vibration of the modal reverb effect from the second set of modes of vibration of the modal reverb effect, wherein adjusting the first set of modes includes adjusting a modal shape of each mode in the first set of modes; and applying the modified modal reverb effect to the audio signal. generating a first set and a second set of vibration modes from one or more vibration modes of a modal reverb effect, wherein each vibration mode included in the first set has a modal frequency corresponding to one of a plurality of frequencies, and wherein each vibration mode included in the second set has a modal frequency that does not correspond to any of the plurality of frequencies; adjusting to modify the modal reverb effect by separating the first set of vibration modes of the modal reverb effect from the second set of vibration modes of the modal reverb effect, wherein the one or more processing devices are configured to adjust a modal shape of each mode included in the first set of modes; and applying the modified modal reverb effect to the audio signal.

14. The system of claim 13, wherein, The plurality of frequencies corresponds to frequencies of notes of a chromatic scale within a specified range.

15. The system of claim 13, wherein, The plurality of frequencies includes two or more frequencies corresponding to notes of a microtonal scale.

16. The system of claim 13, wherein, The plurality of frequencies corresponds to a subset of frequencies of notes of a chromatic scale.

17. The system of claim 16, wherein, The one or more processing devices are configured to receive input indicative of a key or a scale, wherein each of the plurality of frequencies corresponds to a frequency of a note included in the key or the scale.

18. The system of claim 16, wherein, The one or more processing devices are configured to receive input indicative of one or more musical instruments, wherein the plurality of frequencies are associated with the one or more musical instruments.

19. The system of claim 18, wherein, The one or more musical instruments include a piano having a plurality of keys, each key corresponding to a frequency, wherein the plurality of frequencies includes the respective frequencies of the plurality of keys.

20. The system of claim 18, 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 wherein the plurality of frequencies includes the corresponding frequencies of the plurality of frets.

21. The system of claim 13, wherein, The plurality of frequencies includes one or more fundamental frequencies, and harmonics of the fundamental frequencies.

22. The system of claim 13, wherein, The one or more processing devices are configured to adjust the vibration modes of the modal reverb effect by adjusting the modal shape to reduce an energy of each mode included in the first set of modes.

23. The system of claim 13, wherein, The one or more processing devices are configured to adjust the vibration modes of the modal reverb effect by adjusting the modal shape to increase an energy of each mode included in the first set of modes.

24. The system of claim 13, wherein, The one or more processing devices are configured to: analyze the audio signal; and determine at least one of a key, a scale, or a musical instrument of the audio signal from the analysis, wherein the determined plurality of frequencies used to modify the modal reverb effect correspond to frequencies of the determined key, scale, or musical instrument.

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