Wearable electronic device with low frequency noise reduction

1. A method comprising:

at a wearable electronic device capable of detecting a voiced speech component, the device having: a first electro-acoustic input transducer and a second electro-acoustic input transducer arranged to pick up a first acoustic signal and convert the first acoustic signal to a first microphone signal and a second microphone signal; and a third electro-acoustic input transducer arranged to pick up a second acoustic signal and convert the second acoustic signal to a third microphone signal; and a processor:

generating a beamformed signal based on the first microphone signal and the second microphone signal;

estimating a first frequency value representing a fundamental frequency of a voiced speech component in one or more of: the first microphone signal, the second microphone signal and the third microphone signal;

configuring a first filter with one or more first passbands, including an upper first passband, at one or more integer multiples of the first frequency value; and one or more first stop bands adjacent the one or more passbands; wherein the first filter has a second passband above the upper passband;

filtering, using the first filter, one or more of: the first microphone signal, the second microphone signal and the beamformed signal.

2. A method according to claim 1 , wherein the first electro-acoustic input transducer and the second electro-acoustic input transducer are arranged to pick up the first acoustic signal from an ambient space; and

wherein the third electro-acoustic input transducer is arranged to pick up the second acoustic signal from an enclosed space different from the ambient space; and

wherein the first frequency value is estimated based on the third microphone signal.

3. A method according to claim 1 , comprising:

detecting periods with presence of voiced speech and periods with absence of voiced speech in one or more of: the first microphone signal, the second microphone signal and the third microphone signal;

in accordance with detecting presence of voiced speech, estimating the first frequency value based on a period with presence of voiced speech.

4. A method according to claim 1 , comprising:

detecting periods with presence of voiced speech and periods with absence of voiced speech in one or more of: the first microphone signal, the second microphone signal and the third microphone signal;

in accordance with detecting absence of voiced speech, reconfiguring the first filter, including dispensing with at least one of the one or more first stop bands.

5. A method comprising:

at a wearable electronic device with: a first electro-acoustic input transducer and a second electro-acoustic input transducer arranged to pick up a first acoustic signal and convert the first acoustic signal to a first microphone signal and a second microphone signal; and a third electro-acoustic input transducer arranged to pick up a second acoustic signal and convert the second acoustic signal to a third microphone signal; and a processor:

generating a beamformed signal based on the first microphone signal and the second microphone signal;

estimating a first frequency value representing a fundamental frequency in one or more of: the first microphone signal, the second microphone signal and the third microphone signal;

configuring a first filter with one or more first passbands, including an upper first passband, at one or more integer multiples of the first frequency value; and one or more first stop bands adjacent the one or more passbands; wherein the first filter has a second passband above the upper passband;

filtering, using the first filter, one or more of: the first microphone signal, the second microphone signal and the beamformed signal and

wherein the second passband is implemented by a high-pass filter with a lower cut-off frequency; comprising:

detecting periods with presence of voiced speech and periods with absence of voiced speech in one or more of: the first microphone signal, the second microphone signal and the third microphone signal;

in accordance with determining absence of voiced speech, reconfiguring the first filter, including setting a lower cut-off frequency of the high-pass filter at a predetermined lower cut-off frequency value.

6. A method according to claim 1 , comprising:

performing frequency spectrum equalization, using a second filter, to compensate for a low-frequency roll-off, of the beamformer.

7. A method according to claim 1 , wherein the first filter has respective gains at the one or more passbands at the one or more integer multiples of the first frequency value; wherein the respective gains compensate for a low frequency roll-off, of the beamformer.

8. A method according to claim 1 , wherein the first filter comprises a comb filter.

9. A method according to claim 1 , wherein the upper first passband is located at a first integer multiple of the first frequency value; and

wherein the first integer multiple is determined based on one or both of: a predetermined integer value and a value based on one or more of: the first microphone signal, the second microphone signal and the third microphone signal.

10. A method according to claim 1 , comprising:

transmitting a signal which is based on the beamformed signal to a remote electronic device.

11. A method according to claim 1 , wherein the wearable electronic device comprises a first electro-acoustic output transducer arranged to emit an acoustic signal at an enclosed space established by at least a portion of the wearable electronic device at a wearer's ear.

12. A method according to claim 1 , comprising:

performing active noise cancellation based on a feedback signal, which is based on the third microphone signal; wherein an active noise cancellation signal is emitted by the first electro-mechanical output transducer.

13. A method according to claim 1 , comprising:

performing short term Fourier transform of one or more of: the first microphone signal, the second microphone signal, the third microphone signal, the first microphone signal when filtered using the first filter, the second microphone signal when filtered using the first filter; and

performing inverse short term Fourier transform of a signal based on the beamformed signal;

wherein one or more of the first filtering, the second filtering, equalization and beamforming is performed in the frequency domain.

14. A wearable electronic device comprising:

a first electro-acoustic input transducer and a second electro-acoustic input transducer arranged to pick up a first acoustic signal and convert the first acoustic signal to a first microphone signal and second microphone signal;

a third electro-acoustic input transducer arranged to pick up a second acoustic signal and convert the second acoustic signal to a third microphone signal; and

a processor configured to generate a beamformed signal based on the first microphone signal and the second microphone signal;

estimate a first frequency value representing a fundamental frequency in one or more of: the first microphone signal, the second microphone signal and the third microphone signal;

configure a first filter with one or more first passbands, including an upper first passband, at one or more integer multiples of the first frequency value; and one or more first stop bands adjacent the one or more passbands; wherein the first filter has a second passband above the upper passband;

filter, using the first filter, one or more of: the first microphone signal, the second microphone signal and the beamformed signal and

wherein the second passband is implemented by a high-pass filter with a lower cut-off frequency; and

detecting periods with presence of voiced speech and periods with absence of voiced speech in one or more of: the first microphone signal, the second microphone signal and the third microphone signal;

in accordance with determining absence of voiced speech, reconfiguring the first filter, including setting a lower cut-off frequency of the high-pass filter at a predetermined lower cut-off frequency value.

15. A signal processing module for a headphone, an earphone or a headset; wherein the signal processing module is configured to perform the method according to claim 14 .