Noise reduction device, noise reduction system, and noise reduction control method

A noise reduction device connectable to a plurality of sound acquisition devices and a plurality of sound output devices that acquire and output sound in a given space around a seat, the noise reduction device comprising:

• a memory that stores, with respect to each of at least an upright seat position control point and a reclined seat position control point at which noise is to be reduced:
• settings of each of the plural sound acquisition devices as either a noise acquisition device, an error acquisition device, or off;
• settings of each of the sound output devices as on or off;
• and a filter transfer coefficient;
• a processor that:
• selects, based on a current position of the seat, the filter transfer coefficient, the sound acquisition device and sound output device settings associated with either the upright seat position control point and the reclined seat position control point stored in the memory,
• determines, for each respective sound signal from the sound acquisition devices, whether the respective sound signal is from a noise sound acquisition device or an error sound acquisition device,
• specifies, for the noise sound acquisition device, a frequency in the sound signal from the noise sound acquisition device as a frequency to be canceled,
• adjusts the selected transfer coefficient based on the sound signal from a sound acquisition device determined to be an error sound acquisition device, and
• generates a cancelation sound signal according to the specified frequency and the adjusted transfer coefficient;
• and
• a control sound transmitter that outputs the cancelation sound signal to at least one of the plurality of sound output devices.