System and method for providing a quiet zone
A system and method for quieting unwanted sound. As a non-limiting example, various aspects of this disclosure provide a system and method, for example implemented in a premises-based or home audio system, for quieting unwanted sound at a particular location.
1. An audio system comprising:
a microphone;
a loudspeaker; and
circuitry operable to:
identify an unwanted sound at a particular location;
filter the unwanted sound to pass a local audio signal comprising a frequency band of sound to be counteracted, wherein a lower frequency of the frequency band is characterized by a particular wavelength;
receive, via the microphone, a remote audio signal, wherein the microphone is positioned at least one fourth of the particular wavelength away from the particular location;
characterize a relationship between the local audio signal and the remote audio signal; and
generate, based at least in part on the local audio signal and the characterized relationship, a cancellation signal that, when output by the loudspeaker, will counteract, at least in part, the unwanted sound.
2. The audio system of claim 1 , wherein the circuitry is operable to characterize the relationship by, at least in part, operating to:
generate a test stimulus signal to cause the loudspeaker to output a test sound;
receive the test sound at the location; and
analyze the test stimulus signal and the received test sound to determine a functional relationship between the test stimulus signal and the received test sound.
3. The audio system of claim 2 , wherein the test stimulus signal comprises a pseudo-random noise signal comprising a pink noise signal.
4. The audio system of claim 2 , wherein the test stimulus signal comprises a swept frequency signal comprising frequencies in a range up to at least twice a quieting passband of the audio system.
5. The audio system of claim 1 , wherein a magnitude of the cancellation signal is set 6-10 dB lower than a level determined for an ideal cancellation.
6. The audio system of claim 1 , wherein the circuitry is operable to characterize the relationship between the sound signal and the received sound by, at least in part, utilizing a plurality of microphones where each of the plurality of microphones is positioned at a respective fixed geographical location.
7. The audio system of claim 6 , wherein each of the respective fixed geographical locations is within a same room of a premises.
8. An audio system comprising:
a plurality of microphones;
a loudspeaker; and
circuitry operable to:
identify an unwanted sound at a particular location;
filter the unwanted sound to pass a local audio signal comprising a frequency band of sound to be counteracted, wherein a lower frequency of the frequency band is characterized by a particular wavelength;
receive, via the plurality of microphones, a plurality of remote audio signals, wherein each of the plurality of microphone is positioned at least one fourth of the particular wavelength away from the particular location;
characterize a relationship between the local audio signal and the plurality of remote audio signals; and
generate, based at least in part on the local audio signal and the characterized relationship, a cancellation signal that, when output by the loudspeaker, will counteract, at least in part, the unwanted sound.
9. The audio system of claim 8 , wherein each of the plurality of microphone is positioned within a same room of a premises.
10. The audio system of claim 8 , wherein the circuitry is operable to characterize the relationship by, at least in part, operating to:
generate a test stimulus signal to cause the loudspeaker to output a test sound;
receive the test sound at the location; and
analyze the test stimulus signal and the received test sound to determine a functional relationship between the test stimulus signal and the received test sound.
11. The audio system of claim 10 , wherein the test stimulus signal comprises a pseudo-random noise signal comprising a pink noise signal.
12. The audio system of claim 10 , wherein the test stimulus signal comprises a swept frequency signal comprising frequencies in a range up to at least twice a quieting passband of the audio system.
13. The audio system of claim 8 , wherein a magnitude of the cancellation signal is set 6-10 dB lower than a level determined for an ideal cancellation.
14. An audio system comprising:
a microphone;
a loudspeaker; and
circuitry operable to:
receive, via the microphone, a remote audio signal, wherein the microphone is positioned at least one fourth of a particular wavelength away from a particular location;
identify an unwanted sound in the remote audio signal;
filter the remote audio signal to pass a frequency band of sound to be counteracted, wherein a lower frequency of the frequency band is characterized by the particular wavelength;
characterize a relationship between a local audio signal, at the particular location, and the filtered remote audio signal; and
generate, based at least in part on the local audio signal and the characterized relationship, a cancellation signal that, when output by the loudspeaker, will counteract, at least in part, the unwanted sound.
15. The audio system of claim 14 , wherein the circuitry is operable to characterize the relationship by, at least in part, operating to:
generate a test stimulus signal to cause the loudspeaker to output a test sound;
receive the test sound at the location; and
analyze the test stimulus signal and the received test sound to determine a functional relationship between the test stimulus signal and the received test sound.
16. The audio system of claim 15 , wherein the test stimulus signal comprises a pseudo-random noise signal comprising a pink noise signal.
17. The audio system of claim 15 , wherein the test stimulus signal comprises a swept frequency signal comprising frequencies in a range up to at least twice a quieting passband of the audio system.
18. The audio system of claim 14 , wherein a magnitude of the cancellation signal is set 6-10 dB lower than a level determined for an ideal cancellation.
19. The audio system of claim 14 , wherein the circuitry is operable to characterize the relationship between the sound signal and the received sound by, at least in part, utilizing a microphone that is outside a target zone of sound cancellation.
20. The audio system of claim 14 , wherein the circuitry is operable to characterize the relationship between the sound signal and the received sound by, at least in part, utilizing a plurality of microphones positioned at fixed geographical locations.