Methods and systems for automatically equalizing audio output based on room position
The various implementations described herein include methods, devices, and systems for automatic audio equalization. In one aspect, a method is performed at an electronic device that includes speakers, microphones, processors and memory. The electronic device outputs audio user content from the speakers and automatically equalizes subsequent audio output of the device without user input. The automatic equalization includes: (1) obtaining audio content signals, including receiving outputted audio content at each microphone; (2) determining from the audio content signals phase differences between microphones; (3) obtaining a feature vector based on the phase differences; (4) obtaining a frequency correction from a correction database based on the obtained feature vector; and (5) applying the obtained frequency correction to the subsequent audio output.
1. A method for equalizing audio output, comprising:
at an electronic device having one or more speakers, a plurality of microphones, one or more processors, and memory:
outputting audio user content from the one or more speakers located in a room; and
automatically and without user input, equalizing subsequent audio output of the electronic device, the equalizing including:
obtaining a collection of audio content signals, including receiving the outputted audio content at each microphone of the plurality of microphones;
determining from the collection of audio content signals a plurality of phase differences between microphones of the plurality of microphones;
obtaining a feature vector based on the plurality of phase differences;
obtaining a frequency correction from a correction database based on the obtained feature vector; and
applying the obtained frequency correction to the subsequent audio output.
2. The method of claim 1 , further comprising:
positioning a speaker device at a particular position within a structure;
outputting via the speaker device training audio;
receiving the outputted training audio at two or more microphones;
generating a reference feature vector and reference frequency correction based on the outputted training audio; and
adding the reference feature vector and reference frequency correction to the correction database.
3. The method of claim 1 , further comprising assigning a plurality of weights to the plurality of phase differences such that each phase difference of the plurality of phase differences is assigned a corresponding weight; and
wherein the feature vector is based on the weighted plurality of phase differences.
4. The method of claim 3 , wherein the plurality of weights is based on a signal-to-noise ratio for the received audio content at each microphone.
5. The method of claim 3 , wherein the plurality of weights is based on relative positioning of the plurality of microphones.
6. The method of claim 1 , further comprising, prior to obtaining the feature vector, determining that the outputted audio content includes audio having a frequency below a transition frequency for the room.
7. The method of claim 1 , prior to obtaining the feature vector, determining that the outputted audio content has an acoustic energy that meets one or more energy criteria for a particular range of frequencies.
8. The method of claim 1 , prior to obtaining the feature vector, determining that the outputted audio content has an audio coherence that meets one or more signal-to-noise criteria.
9. A computing system comprising: one or more processors; and memory coupled to the one or more processors, the memory storing one or more programs configured to be executed by the one or more processors, the one or more programs including instructions for: outputting audio user content from the one or more speakers located in a room; and automatically and without user input, equalizing subsequent audio output of the electronic device, the equalizing including: obtaining a collection of audio content signals, including receiving the outputted audio content at each microphone of the plurality of microphones; determining from the collection of audio content signals a plurality of phase differences between microphones of the plurality of microphones; obtaining a feature vector based on the plurality of phase differences; obtaining a frequency correction from a correction database based on the obtained feature vector; and applying the obtained frequency correction to the subsequent audio output.
10. The system of claim 9 , wherein applying the obtained frequency correction comprises adjusting a gain for a particular range of frequencies.
11. The system of claim 9 , wherein the correction database includes a plurality of feature vectors, each feature vector having a corresponding frequency correction.
12. The system of claim 11 , wherein obtaining the frequency correction from the correction database comprises:
identifying a first feature vector of the plurality of feature vectors based on a comparison with the obtained feature vector; and
selecting the frequency correction that corresponds to the first feature vector.
13. The system of claim 9 , wherein determining the plurality of phase differences includes:
designating a plurality of microphone pairs from the plurality of microphones; and
for each microphone pair of the plurality of microphone pairs, determining a phase difference between the received audio content at each microphone in the microphone pair.
14. The system of claim 9 , wherein equalizing subsequent audio output comprises equalizing a frequency band of subsequent audio output.
15. The system of claim 14 , wherein the frequency band consists of a plurality of sub-bands; and
wherein determining the plurality of phase differences comprises, for a first and second microphone of the plurality of microphones:
for each sub-band of the plurality of sub-bands, determining a corresponding phase difference between the first and second microphones; and
wherein the feature vector is composed at least in part by concatenating a predefined function of the plurality of phase differences.
16. A non-transitory computer-readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing system, cause the system to: output audio user content from the one or more speakers located in a room; and automatically and without user input, equalize subsequent audio output of the electronic device, the equalizing including: obtaining a collection of audio content signals, including receiving the outputted audio content at each microphone of the plurality of microphones; determining from the collection of audio content signals a plurality of phase differences between microphones of the plurality of microphones; obtaining a feature vector based on the plurality of phase differences; obtaining a frequency correction from a correction database based on the obtained feature vector; and applying the obtained frequency correction to the subsequent audio output.
17. The storage medium of claim 16 , wherein obtaining the feature vector comprises applying a fast Fourier transform (FFT) to the plurality of phase differences.
18. The storage medium of claim 16 , wherein the correction database is stored at the electronic device.
19. The storage medium of claim 16 , wherein receiving the outputted audio content at each microphone comprises receiving outputted audio content for a predetermined time period.
20. The storage medium of claim 16 , wherein the audio user content comprises music or audible output from a voice assistant application executing on the computing system.