Spatial headphone transparency

A method performed by an audio system for controlling a transparency function, the method comprising:

• determining an adaptive path estimation filter whose transfer function estimates a path from an input of an earpiece speaker to an output of an interior microphone of a headset, using a playback signal that is driving the earpiece speaker and using an output signal from the interior microphone;
• determining an adaptive output filter that has an input coupled to receive a reference signal produced by an exterior microphone of the headset and an output that is driving the earpiece speaker;
• and
• adapting the output filter into any one of a plurality of different conditions, wherein in a first condition the adaptive output filter produces an output signal that is to recreate through the earpiece speaker an ambient sound that is sensed in the reference signal, in a second condition the adaptive output filter is being determined using the adaptive path estimation filter and is producing an anti-noise signal to cancel the ambient sound, and in a third condition the adaptive output filter is producing an output signal that is to cancel the ambient sound in a portion of an audio band while recreating the ambient sound through the earpiece speaker in another portion of the audio band.

A headset comprising:

• an exterior microphone;
• an interior microphone;
• an acoustic noise cancellation, ANC, subsystem that receives an error signal derived from the interior microphone and produces an anti-noise signal to cancel ambient sound;
• a hear through mode filter having an input to receive a reference signal from the exterior microphone and produce an output signal that reproduces an ambient sound environment of the headset;
• and
• a summing unit having a first input to receive the anti-noise signal and a second input to receive the output signal of the hear through mode filter and an output to produce a speaker driver signal.