System and method for augmenting an acoustic space
A method and system for real-time auralization is described in which room sounds are reverberated and presented over loudspeakers, thereby augmenting the acoustics of the space. Room microphones are used to capture room sound sources, with their outputs processed in a canceler to remove the synthetic reverberation also present in the room. Doing so gives precise control over the auralization while suppressing feedback. It also allows freedom of movement and creates a more natural acoustic environment for performers or participants in music, theater, gaming, home entertainment, and virtual reality applications. Canceler design methods are described, including techniques for handling varying loudspeaker-microphone transfer functions such as would be present in the context of a performance or installation.
1. A system for reducing feedback resulting from a sound produced by a speaker being captured by a microphone, the sound including auralization effects, the system comprising:
an auralizer for producing the auralization effects; and
a canceler, wherein the canceler includes a cancellation filter that is based on an impulse response between the microphone and the speaker, and wherein the impulse response is formed according to acoustics of a live acoustic space in which the microphone and the speaker are separately placed, and wherein the acoustics include at least an acoustic propagation delay between the speaker and the microphone.
2. The system of claim 1 , wherein the cancellation filter is calibrated based on relative positions of the microphone and the speaker in the live acoustic space.
3. The system of claim 1 , wherein the microphone is one of a plurality of microphones, and wherein the speaker is one of a plurality of speakers, and wherein the cancellation filter is based on impulse responses between each microphone-speaker pair of the plurality of microphones and the plurality of speakers.
4. The system of claim 1 , wherein the auralization effects include artificial reverberation.
5. The system of claim 4 , wherein the artificial reverberation is performed in accordance with a target acoustic space that is different from the live acoustic space.
6. The system of claim 1 , wherein the microphone further captures live sound, the canceler being operative to reduce feedback caused by the acoustics of the live acoustic space before the live sound is processed by the auralizer and output to the speaker as the sound with the auralization effects.
7. The system of claim 1 , wherein the auralizer and the canceler are implemented by a digital audio workstation.
8. A method for reducing feedback resulting from a sound produced by a speaker being captured by a microphone, the sound including auralization effects, the system comprising:
capturing live sound by the microphone; and
performing cancelation on the live sound using a cancellation filter that is based on an impulse response between the microphone and the speaker, the cancelation resulting in a live sound estimate, and wherein the impulse response is formed according to acoustics of a live acoustic space in which the microphone and the speaker are separately placed, and wherein the acoustics include at least an acoustic propagation delay between the speaker and the microphone.
9. The method of claim 8 , further including adding the auralization effects to the live sound estimate and providing the live sound estimate with the added auralization effects to the speaker.
10. The method of claim 8 , wherein the cancellation filter is calibrated based on relative positions of the microphone and the speaker in the live acoustic space.
11. The method of claim 8 , wherein the microphone is one of a plurality of microphones, and wherein the speaker is one of a plurality of speakers, and wherein the cancellation filter is based on impulse responses between each microphone-speaker pair of the plurality of microphones and the plurality of speakers.
12. The method of claim 9 , wherein adding the auralization effects includes performing artificial reverberation.
13. The method of claim 12 , wherein the artificial reverberation is performed in accordance with a target acoustic space that is different from the live acoustic space.
14. A method for reducing feedback resulting from a sound produced by a speaker being captured by a microphone, the sound including auralization effects, the method comprising:
generating a live sound without auralization effects from the speaker in a live acoustic space;
capturing the live sound by the microphone;
measuring an impulse response between the microphone and the speaker using the captured live sound; and
using the measured impulse response to obtain characteristics of a cancellation filter wherein the cancellation filter is configured to reduce effects of at least acoustics of a live acoustic space in which the microphone and the speaker are separately placed, and wherein the acoustics include at least an acoustic propagation delay between the speaker and the microphone.
15. The method of claim 14 , wherein the measured impulse response is a function of frequency and time.
16. The method of claim 14 , wherein the characteristics of the cancellation filter further include a windowing function.