Apparatus, method and computer program for rendering a spatial audio output signal

1. A method comprising;

using a first microphone and a second microphone to detect ambient noise where the first microphone is positioned at a first position within a headset and the second microphone is positioned at a second position within the headset;

comparing the ambient noise detected by the first microphone to the ambient noise detected by the second microphone to determine locations of the microphones;

using the determined locations of the microphones to enable a spatial audio output signal to be rendered by the headset;

using the locations of the microphones to determine whether or not the headset is being worn; and

in response to determining that the headset is not being worn, pausing the spatial audio output signal rendered by the headset.

2. A method as claimed in claim 1 , wherein rendering the spatial audio output signal comprises using the determined locations of the microphones to select one or more filters for the user of the headset and using the one or more filters to generate the spatial audio output signal comprising a directional audio output signal based on the determined locations of the microphones.

3. A method as claimed in claim 2 , wherein comparing the ambient noise detected by the first microphone to the ambient noise detected by the second microphone comprises:

correlating signals detected by the microphones to calculate a time difference of arrival values between the ambient noise detected by the first microphone and the ambient noise detected by a second microphone;

plotting a histogram of the time difference of arrival values; and

determining locations of the microphones using the histogram.

4. A method as claimed in claim 3 , wherein the width of the histogram is used to estimate the time difference.

5. A method as claimed in claim 3 , further applying a model of a human head shape to select the one or more filters from the estimated time difference.

6. A method as claimed in claim 3 , wherein a ratio of high frequency ambient noise to low frequency ambient noise at different parts of the histogram is used to estimate the location of the microphones to enable the one or more filters to be selected.

7. A method as claimed in claim 1 , wherein comparing comprises comparing a power spectrum of signals detected by the first microphone and a power spectrum of signals detected by the second microphone to determine a level difference.

8. A method as claimed in claim 1 , wherein determining the location of the microphones comprises at least one of:

determining a distance between the first microphone and the second microphone; and

determining the location of the microphones relative to the front of a user's head.

9. A method as claimed in claim 1 , wherein comparing of the ambient noise detected by the first microphone to the ambient noise detected by the second microphone occurs automatically while the headset is rendering an audio output signal.

10. An apparatus comprising:

processing circuitry; and

memory circuitry including computer program code, the memory circuitry and the computer program code configured to, with the processing circuitry, enable the apparatus to:

detect ambient noise by using a first microphone and a second microphone where the first microphone is positioned at a first position within a headset and the second microphone is positioned at a second position within the headset;

compare the ambient noise detected by the first microphone to the ambient noise detected by the second microphone to determine locations of the microphones;

generate a spatial audio output signal to be rendered by the headset based on the determined locations of the microphones;

use the locations of the microphones to determine whether or not the headset is being worn; and

in response to determining that the headset is not being worn, pause the spatial audio output signal rendered by the headset.

11. An apparatus as claimed in claim 10 , wherein one or more filters is selected in order to render the spatial audio output signal for the user of the headset and the one or more filters enable a directional audio output signal based on the determined locations of the microphones.

12. An apparatus as claimed in claim 11 , wherein the apparatus is enabled to compare the ambient noise detected by the first microphone to the ambient noise detected by the second microphone further configured to:

correlate signals detected by the microphones to calculate a time difference of arrival values between the ambient noise detected by the first microphone and the ambient noise detected by the second microphone;

plot a histogram of the time difference of arrival values; and

determine locations of the microphones using the histogram.

13. An apparatus as claimed in claim 12 , wherein the time difference is estimated based on the width of the histogram.

14. An apparatus as claimed in claim 12 , wherein the one or more filters is selected from the estimated time difference and based on a model of a human head shape.

15. An apparatus as claimed in claim 12 , wherein a ratio of high frequency ambient noise to low frequency ambient noise at different parts of the histogram is used to estimate level differences to select the one or more filters.

16. An apparatus as claimed in claim 10 , wherein the apparatus is further configured to compare a power spectrum of signals detected by the first microphone and a power spectrum of signals detected by the second microphone to determine a level difference.

17. An apparatus as claimed in claim 10 , wherein the location of the microphones is determined so as to determine at least one of:

a distance between the first microphone and the second microphone; and

the location of the microphones relative to the front of a user's head.

18. An apparatus as claimed in any of claim 10 , wherein the ambient noise detected by the first microphone is compared to the ambient noise detected by the second microphone automatically while the headset is rendering an audio output signal.

19. An apparatus comprising:

processing circuitry; and

memory circuitry including computer program code, the memory circuitry and the computer program code configured to, with the processing circuitry, enable the apparatus to:

detect ambient noise by using a first microphone and a second microphone where the first microphone is positioned at a first position within a headset and the second microphone is positioned at a second position within the headset;

compare the ambient noise detected by the first microphone to the ambient noise detected by the second microphone to determine locations of the microphones, wherein the apparatus is enabled to compare the ambient noise detected by the first microphone to the ambient noise detected by the second microphone by correlating signals detected by the microphones to calculate a time difference of arrival values between the ambient noise detected by the first microphone and the ambient noise detected by the second microphone, plotting a histogram of the time difference of arrival values and determining locations of the microphones using the histogram; and

generate a spatial audio output signal to be rendered by the headset based on the determined locations of the microphones,

wherein one or more filters is selected in order to render the spatial audio output signal for the user of the headset and the one or more filters enable a directional audio output signal based on the determined locations of the microphones, and

wherein a ratio of high frequency ambient noise to low frequency ambient noise at different parts of the histogram is used to estimate level differences to select the one or more filters.