Accoustic processor for a mobile device

1. An acoustic processor for a mobile device, the mobile device comprising a speaker including a speaker membrane, the speaker membrane having a first speaker membrane side and second speaker membrane side opposite the first speaker membrane side, a mobile device housing having a first aperture at a front side of the mobile device for providing a first acoustic path between the first speaker membrane side and the exterior of the mobile device and having a second aperture at a back side of the mobile device for providing a second acoustic path between the second speaker membrane side and the exterior of the mobile device;

the acoustic processor being configured and arranged to:

sense a signal on an acoustic processor input, the signal being induced on at least one terminal of the speaker in response to acoustic waves received from an acoustic source that is behind the mobile device and from an acoustic source that is in front of the mobile device;

process the induced signal to discriminate between the acoustic waves received from the acoustic source that is behind the mobile device and from the acoustic source that is in front of the mobile device;

and output the processed signal on an acoustic processor output.

2. The acoustic processor of claim 1 further configured to mix the induced signal with a further signal sensed via a microphone.

3. The acoustic processor of claim 2 wherein the acoustic processor is further configured to equalize the induced signal and to apply beam-forming to the induced signal and the further signal.

4. The acoustic processor of claim 2 further configured to determine a signal to noise ratio from at least one of the induced signal and the further signal and to alter the mixing ratio between the induced signal and the further signal dependent on the signal to noise ratio.

5. The mobile device comprising the acoustic processor of claim 1 and comprising a speaker including a speaker membrane, the speaker membrane having a first speaker membrane side and second speaker membrane side opposite the first speaker membrane side, and a mobile device housing having a first aperture at a front side of the mobile device for providing a first acoustic path between the first speaker membrane side and the exterior of the mobile device, and having a second aperture at a back side of the mobile device for providing a second acoustic path between the second speaker membrane side and the exterior of the mobile device and wherein mobile device is operable to configure the speaker as a microphone and the acoustic processor input is coupled to the at least one speaker terminal.

6. The mobile device of claim 5 comprising a camera wherein the mobile device is configurable in a camcorder mode of operation, and the acoustic processor is further configured to store the processed signal.

7. The mobile device of claim 5 comprising a camera and wherein the mobile device is configurable in a video call mode, and further configured to transmit the processed signal to a receiver of a video call.

8. The mobile device of any of claim 5 configured as one of a mobile phone, a wearable device, a portable audio player, a personal digital assistant, a laptop, a tablet computer.

9. A method of acoustic processing for a mobile device, the mobile device comprising a speaker including a speaker membrane, the speaker membrane having a first speaker membrane side and second speaker membrane side opposite the first speaker membrane side, a mobile device housing having a first aperture at a front side of the mobile device and having a second aperture at a back side of the mobile device for providing for acoustically coupling each speaker membrane side to the exterior of the mobile device,

the method comprising:

sensing a signal induced on at least one terminal of the speaker in response to acoustic waves received from an acoustic source that is behind the mobile device and from an acoustic source that is in front of the mobile device,

processing the induced signal to discriminate between the acoustic waves received from the acoustic source that is behind the mobile device and from the acoustic source that is in front of the mobile device; and

outputting the processed signal.

10. The method of claim 9 comprising sensing a further signal via a microphone, and combining the induced signal and the further signal.

11. The method of claim 10 further comprising estimating the signal to noise ratio from the further signal.

12. The method of claim 10 further comprising estimating the signal to noise ratio value from the induced signal.

13. The method of claim 10 wherein processing the induced signal comprises at least one of attenuating the induced signal for a signal to noise ratio value above a predetermined threshold and attenuating the further signal for a signal to noise ratio value below the predetermined threshold.

14. In a mobile device comprising a speaker including a speaker membrane, the speaker membrane having a first speaker membrane side and second speaker membrane side opposite the first speaker membrane side, a mobile device housing having a first aperture at a front side of the mobile device for providing a first acoustic path between the first speaker membrane side and the exterior of the mobile device and having a second aperture at a back side of the mobile device for providing a second acoustic path between the second speaker membrane side and the exterior of the mobile device,

the use of the speaker to function as a directional microphone to discriminate between acoustic waves received from an acoustic source that is behind the mobile device and from an acoustic source that is in front of the mobile device.