Calibrating listening devices

1. A method of calibrating a listening device configured to be worn on a head of a user, the method comprising:

determining a first head related transfer function (HRTF) of a first portion of the user's anatomy using the listening device while the listening device is worn on the user's head;

determining a second HRTF of a second portion of the user's anatomy, wherein the second portion of the user's anatomy is a different portion of the user's anatomy than the first portion of the user's anatomy;

combining portions of the first and second HRTFs to generate a composite HRTF of the user, wherein the composite HRTF is personalized to the first and second portions of the user's anatomy; and,

calibrating the listening device for the user based on the composite HRTF.

2. The method of claim 1 wherein determining the first HRTF comprises determining or estimating a shape of the user's head.

3. The method of claim 1 wherein the listening device includes a first earphone having a first transducer and a second earphone having a second transducer, wherein determining the first HRTF comprises emitting an audio signal from the first transducer and receiving a portion of the emitted audio signal at the second transducer.

4. The method of claim 1 wherein determining the first HRTF comprises determining an interaural time difference (ITD) or an interaural level distance (ILD) of an audio signal emitted from a position proximate the user's head.

5. The method of claim 1 , further comprising:

determining a third HRTF of a third portion of the user's anatomy,

wherein the first and third portions of the user's anatomy comprise respectively the user's left ear and right ear, and

wherein the second portion of the user's anatomy comprises a portion of the user's neck or torso.

6. The method of claim 1 wherein the listening device includes an earphone that defines a cavity having an inner surface, wherein a first transducer is disposed proximate the inner surface, and wherein automatically determining the second HRTF further comprises:

emitting an audio signal from the first transducer;

receiving a portion of the audio signal at a second transducer in fluid communication with the cavity; and

calculating the second HRTF using a difference between the emitted audio signal and the received portion of the audio signal.

7. The method of claim 1 wherein the listening device includes an earphone having an inner surface comprising a material with an absorption coefficient between about 0.40 and 1.0 inclusive.

8. The method of claim 1 wherein determining the first HRTF comprises a first HRTF modality, and wherein determining the second HRTF comprises a different, second HRTF modality.

9. The method of claim 1 wherein the listening device includes an earphone coupled to a headband, and wherein determining the first HRTF further comprises:

receiving positional signals indicative of movement of the earphone from a first position to a second position relative to the headband.

10. The method of claim 1 wherein determining the first HRTF further comprises:

receiving a first photograph of the user's head without a headset;

receiving a second photograph of the user's head having the headset worn thereon;

identifying at least a portion of the user's head in the first photograph;

identifying at least a first portion of the headset in the second photograph; and

calibrating the first photograph using at least the first portion of the headset in the second photograph.

11. The method of claim 1 wherein determining the second HRTF further comprises:

emitting sounds from a transducer spaced apart from the user's ear in a non-anechoic environment; and

receiving sounds at a transducer positioned on a body configured to be worn in an opening of an ear canal of at least one of the user's ears.

12. A method of determining a head related transfer function (HRTF) of a user, the method comprising:

receiving ambient sound energy from the user's environment at one or more transducers attached to a listening device configured to be worn by the user, wherein the one or more transducers are configured to convert the sound energy to electrical audio signals; and

determining the user's HRTF using a processor coupled to the one or more transducers, wherein the determining is performed by the processor using the electrical audio signals in the absence of an input signal corresponding to the sound energy received at the one or more transducers;

wherein determining the user's HRTF comprises:

determining a first HRTF of a first portion of the user's anatomy using the listening device while the listening device is worn on the user's head;

determining a second HRTF of a second portion of the user's anatomy, wherein the second portion of the user's anatomy is a different portion of the user's anatomy than the first portion of the user's anatomy; and

combining portions of the first and second HRTFs to generate the user's HRTF.

13. The method of claim 12 wherein the one or more transducers comprise a transducer array, and wherein determining the user's HRTF further comprises beamforming the electrical audio signals to determine a location of one or more sound sources in the user's environment.

14. The method of claim 12 , further comprising:

storing the electronic audio signals as audio data; and

creating a generic audio recording using the audio data, wherein creating the generic audio recording comprises removing HRTF information specific to the user from the audio data.

15. The method of claim 12 where determining the user's HRTF further comprises generating a reverberation model of the user's environment using the electrical audio signals.

16. A listening device configured to be worn on a head of a user, the listening device comprising:

a pair of earphones coupled via a headband, wherein each of the earphones defines a cavity having an inner surface, and wherein a plurality of transducers disposed proximate the inner surface;

at least one sensor configured to produce movement signals indicative of movement of the user's head; and

a communication component coupled to the pair of earphones and to the sensor and configured to transmit and receive data,

wherein the communication component is configured to communicatively couple the earphones and the sensor to a computing device, and

wherein the computing device is configured to compute at least a portion of the user's head related transfer function (HRTF) by:

determining a first HRTF of a first portion of the user's anatomy using the listening device while the listening device is worn on the user's head;

determining a second HRTF of a second portion of the user's anatomy, wherein the second portion of the user's anatomy is a different portion of the user's anatomy than the first portion of the user's anatomy; and

combining portions of the first and second HRTFs to generate the user's HRTF.

17. The listening device of claim 16 wherein at least a portion of the inner surface of the cavity of each earphone includes a material having an absorption coefficient between about 0.40 and 1.0 inclusive.

18. The listening device of claim 16 wherein the plurality of transducers on each earphone includes at least one speaker and at least one microphone.

19. The listening device of claim 16 wherein the plurality of transducers on each earphone includes a first transducer above the user's pinna, a second transducer in front of the user's pinna, a third transducer behind the user's pinna and a fourth transducer that axially overlaps the user's pinna when the listening device is worn on the user's ear.