Various acoustic manipulation and microphone gain adjustment techniques are enabled. For instance, a method comprises receiving, by a voice-enabled device comprising a processor and from a microphone, an input comprising environmental audio, determining, by the voice-enabled device, a level of the environmental audio, determining, by the voice-enabled device, a gain-adjust value based on the environmental audio, and adjusting, by the voice-enabled device, a gain of the microphone by the gain-adjust value.

Various acoustic manipulation and microphone gain adjustment techniques are enabled. For instance, a method comprises receiving, by a voice-enabled device comprising a processor and from a microphone, an input comprising environmental audio, determining, by the voice-enabled device, a level of the environmental audio, determining, by the voice-enabled device, a gain-adjust value based on the environmental audio, and adjusting, by the voice-enabled device, a gain of the microphone by the gain-adjust value.

A volume adjustment device includes a microphone, a speaker, and a signal processing unit. The at least one signal processing unit includes at least one processor and at least one memory. The signal processing unit is configured to output a measurement sound from the speaker. The signal processing unit is also configured to measure a first impulse response with the microphone. The signal processing unit is also configured to adjust a volume of the measurement sound output from the speaker based on a direct sound component of the first impulse response and an indirect sound component of the first impulse response.

A volume adjustment device includes a microphone, a speaker, and a signal processing unit. The at least one signal processing unit includes at least one processor and at least one memory. The signal processing unit is configured to output a measurement sound from the speaker. The signal processing unit is also configured to measure a first impulse response with the microphone. The signal processing unit is also configured to adjust a volume of the measurement sound output from the speaker based on a direct sound component of the first impulse response and an indirect sound component of the first impulse response.

A method for inducing brain waves by sound has the following steps: receiving a first channel input signal and a second channel input signal; adjusting a volume gain of the first channel input signal to form a first channel output signal, wherein a format of the volume gain of the first channel output signal is a first wave format; adjusting a volume gain of the second channel input signal to form a second channel output signal, wherein a format of the volume gain of the second channel output signal is a second wave format, wherein there is a phase difference between the first wave format and the second wave format, wherein the formats of the first wave format and the second wave format are the same; outputting the first channel output signal to a first speaker; and outputting the second channel output signal to a second speaker.

A method for inducing brain waves by sound has the following steps: receiving a first channel input signal and a second channel input signal; adjusting a volume gain of the first channel input signal to form a first channel output signal, wherein a format of the volume gain of the first channel output signal is a first wave format; adjusting a volume gain of the second channel input signal to form a second channel output signal, wherein a format of the volume gain of the second channel output signal is a second wave format, wherein there is a phase difference between the first wave format and the second wave format, wherein the formats of the first wave format and the second wave format are the same; outputting the first channel output signal to a first speaker; and outputting the second channel output signal to a second speaker.

Provided is an analog switch circuit that allows switching between an on-state and an off-state according to a control signal, the analog switch circuit including a main input terminal that receives an input voltage, an output terminal, an upper-side power supply terminal that receives an upper supply voltage, a lower-side power supply terminal that receives a lower supply voltage, a main N-channel MOS transistor and a main P-channel MOS transistor that are disposed in parallel between the main input terminal and the output terminal, and a controller that includes a voltage generating circuit that generates a high-side voltage according to the upper supply voltage and the input voltage and a low-side voltage according to the input voltage and the lower supply voltage. The controller can control a gate and a back gate of each of the main N-channel and P-channel MOS transistors based on the high-side and low-side voltages.

Provided is an analog switch circuit that allows switching between an on-state and an off-state according to a control signal, the analog switch circuit including a main input terminal that receives an input voltage, an output terminal, an upper-side power supply terminal that receives an upper supply voltage, a lower-side power supply terminal that receives a lower supply voltage, a main N-channel MOS transistor and a main P-channel MOS transistor that are disposed in parallel between the main input terminal and the output terminal, and a controller that includes a voltage generating circuit that generates a high-side voltage according to the upper supply voltage and the input voltage and a low-side voltage according to the input voltage and the lower supply voltage. The controller can control a gate and a back gate of each of the main N-channel and P-channel MOS transistors based on the high-side and low-side voltages.

An apparatus, method and computer program product for: providing spatial audio information at a defined output volume level, the spatial audio information comprising at least a first audio signal and a second audio signal, receiving a user input for concurrently adjusting a volume level of the first audio signal and a volume level of the second audio signal, determining a type of the user input, and adjusting, based on the type of the user input, the volume level of the first audio signal and the volume level of the second audio signal while maintaining the defined output volume level.

An apparatus, method and computer program product for: providing spatial audio information at a defined output volume level, the spatial audio information comprising at least a first audio signal and a second audio signal, receiving a user input for concurrently adjusting a volume level of the first audio signal and a volume level of the second audio signal, determining a type of the user input, and adjusting, based on the type of the user input, the volume level of the first audio signal and the volume level of the second audio signal while maintaining the defined output volume level.