Acoustic devices and methods for determining transfer functions thereof

An acoustic device, comprising a sound production unit, a first detector, a processor, and a fixing structure, wherein:

• the sound production unit is configured to generate a first sound signal according to a noise reduction control signal, wherein the sound production unit is a speaker;
• the first detector is configured to obtain a first residual signal, the first residual signal comprising a residual noise signal formed by superimposition of an environmental noise and the first sound signal at a location where the first detector is located, wherein the first detector is a microphone;
• the processor is configured to:
• obtain a first transfer function between the sound production unit and the first detector, a second transfer function between the sound production unit and a target spatial location, and a fifth transfer function reflecting a relationship among an environmental noise source, the first detector, and the target spatial location;
• estimate a second residual signal at the target spatial location based on the first transfer function, the second transfer function, the fifth transfer function, the first sound signal, and the first residual signal;
• and
• update the noise reduction control signal based on the second residual signal;
• and
• the fixing structure is configured to place the acoustic device at a location near a user's ear but not blocking the user's ear canal, the target spatial location being closer to the user's ear canal than the first detector.

A method for determining a transfer function of an acoustic device, wherein the acoustic device includes a sound production unit, a first detector, a processor, and a fixing structure, and the fixing structure is configured to place the acoustic device at a location near a tester's ear but not blocking the tester's ear canal, wherein the method comprises:

• obtaining, in a scenario in which no environmental noise exists, a first signal generated by the sound production unit based on a noise reduction control signal and a second signal obtained by the first detector, wherein the second signal includes a residual noise signal transmitted by the first signal to the first detector;
• determining a first transfer function between the sound production unit and the first detector based on the first signal and the second signal;
• obtaining a third signal obtained by a second detector, wherein the second detector is disposed at a target spatial location, the target spatial location is closer to the tester's ear canal than the first detector, and the third signal includes a residual noise signal transmitted by the first signal to the target spatial location;
• determining a second transfer function between the sound production unit and the target spatial location based on the first signal and the third signal;
• obtaining, in a scenario in which the environmental noise exists and the sound production unit does not generate any signal, a fourth signal obtained by the first detector and a fifth signal obtained by the second detector;
• determining a third transfer function between an environmental noise source and the first detector based on the environmental noise and the fourth signal;
• and
• determining a fourth transfer function between the environmental noise source and the target spatial location based on the environmental noise and the fifth signal.