Headphone audio controller
Headphone audio controllers are disclosed. In one implementation, a headphone includes: an acoustic transducer that is configured to develop sound for delivery to an ear of a user; a microphone that is configured to sense sound from the acoustic transducer and develop an output; and a processor, responsive to the microphone output, and that is configured to: determine first and second audio transfer functions between the acoustic transducer and the microphone, and calculate an audio controller based on both the first audio transfer function and the second audio transfer function.
1. A headphone comprising:
an acoustic transducer that is configured to develop sound for delivery to an ear of a user;
a microphone that is configured to sense sound from the acoustic transducer and develop an output; and
a processor, responsive to the microphone output, and that is configured to:
determine first and second audio transfer functions between the acoustic transducer and the microphone, and
calculate an audio controller based on both the first audio transfer function and the second audio transfer function.
2. The headphone of claim 1 , wherein the first audio transfer function is determined without a controller applied.
3. The headphone of claim 1 , wherein the second audio transfer function is determined with a controller applied.
4. The headphone of claim 3 , wherein the controller that is applied is a feedback controller.
5. The headphone of claim 4 , wherein determining the second audio transfer function comprises:
providing an audio signal that is configured to operate the acoustic transducer to generate sound,
sensing the sound with the microphone, and
calculating the second audio transfer function based on the audio signal, the sensed sound, and the controller.
6. The headphone of claim 1 , wherein determining the first and second audio transfer functions comprises providing an audio signal that is configured to operate the acoustic transducer to generate sound and sensing the sound with the microphone.
7. The headphone of claim 6 , wherein the first and second audio transfer functions are determined based on the audio signal and the sensed sound.
8. The headphone of claim 1 , wherein determining the second audio transfer function comprises calculating the second audio transfer function based on both the first audio transfer function and a controller.
9. The headphone of claim 1 , wherein the audio controller comprises an equalization (EQ) controller.
10. The headphone of claim 1 , wherein the audio controller comprises a controller for a headphone use mode, wherein sound external to the headphone is reproduced by the acoustic transducer.
11. The headphone of claim 1 , wherein the processor is further configured to provide a measured power spectrum for a microphone located in an ear canal of a person, and provide a measured power spectrum for a microphone located on the person's head.
12. The headphone of claim 11 , wherein the calculation of the audio controller is further based on both the measured power spectrum for the microphone located in an ear canal of a person and the measured power spectrum for the microphone located on a person's head.
13. The headphone of claim 1 , wherein the calculation of the audio controller is further based on a third audio transfer function between the acoustic transducer, and a microphone located in an ear canal of a person.
14. The headphone of claim 1 , wherein the processor is further configured to provide a third audio transfer function between a first location of a microphone in an ear canal of a person and a second location on the person's head.
15. The headphone of claim 14 , wherein the processor is further configured to provide a fourth audio transfer function between the acoustic transducer and a first location of a microphone in an ear canal of a person.
16. The headphone of claim 15 , wherein the processor is further configured to provide first and second constant values.
17. The headphone of claim 16 , wherein the first and second constant values are calculated based on both the third and fourth audio transfer functions.
18. The headphone of claim 17 , wherein the first and second constant values are calculated based on both the third and fourth audio transfer functions at multiple different fits of the headphone on multiple different people.
19. The headphone of claim 16 , wherein the first and second constant values represent frequency-dependent complex quantities.
20. The headphone of claim 1 , wherein the microphone is a feedback microphone.