Abstract: A signal processing device includes: a processor; and a memory having instructions. The instructions, when executed by the processor, cause the signal processing device to perform operations. The operations include performing a modulation processing of modulating a sound signal by using a modulation parameter based on an interaural phase difference at a listening position of the sound signal.

Abstract: An acoustic processing device mountable on a vehicle, the acoustic processing device includes: a memory; and a processor coupled to the memory, and when executing a program stored in the memory, performs operations. The operations include: outputting a noise level obtained by subtracting a sound source level from a microphone level; outputting a velocity noise level indicating a frequency characteristic of a noise based on a velocity of the vehicle; outputting a volume sound source level; outputting an SN ratio which is a ratio between the volume sound source level and the velocity noise level; selecting based on the SN ratio, the estimated noise level candidates including a level related to the noise level and the velocity noise level; and outputting a selected one of the estimated noise level candidates as an estimated noise level.

Abstract: A signal processing device includes: a processor; and a memory having instructions. The instructions, when executed by the processor, cause the signal processing device to perform operations. The operations include performing a modulation processing of modulating a sound signal by using a modulation parameter based on an interaural phase difference at a listening position of the sound signal.

Abstract: An active noise reduction device includes a standard signal generator, adaptive filters, a control sound emitter, and an error signal detector. The standard signal generator generates a standard signal including harmonics of a fundamental frequency correlated with the control target sound. The adaptive filters each generates corresponding one of harmonic components of a control signal based on the standard signal. The adaptive filters each is for corresponding one of the harmonics. The control sound emitter emits a control sound based on the control signal. The error signal detector collects residual noise left over after interference between the control target sound and the control sound, and detects an error signal based on the residual noise. Each of the adaptive filters includes a step size determiner. The step size determiner sets the step size parameter based on a frequency variation in the corresponding one of the harmonic components of the standard signal.

Abstract: An active noise reduction device includes a standard signal generator, an adaptive filter unit, a control sound output unit, and an error signal detector. The adaptive filter unit includes a control signal generator, a filter coefficient update unit, and a step size setting unit. The control signal generator multiplies a standard signal by a filter coefficient to generate a control signal. Based on a reference signal and an error signal, the filter coefficient update unit updates the filter coefficient so as to minimize the error signal. The step size determiner sets a step size parameter indicating an update amount of the filter coefficient. The filter coefficient update unit sets a step size adjustment coefficient for adjusting the step size parameter based on an audio information feature amount and a change of the control signal.

Abstract: A fake engine sound control device includes an environment information acquisition unit, a vehicle speed acquisition unit, an engine speed acquisition unit, a fake engine sound generator, and a fake engine sound controller. The environment information acquisition unit acquires environment information. The vehicle speed acquisition unit acquires vehicle speed information. The engine speed acquisition unit acquires rotation speed information. The fake engine sound generator generates a fake engine sound. The fake engine sound controller determines, based on the environment information and the vehicle speed information, whether leading to a target vehicle speed is required, the target vehicle speed being different from the vehicle speed indicated by the vehicle speed information, and controls, when leading to the target vehicle speed is required, the fake engine sound generator based on the target vehicle speed and the rotation speed information.

Abstract: An active noise reduction device includes a standard signal generator, an adaptive filter unit, a control sound output unit, and an error signal detector. The adaptive filter unit includes a control signal generator, a filter coefficient update unit, and a step size setting unit. The control signal generator multiplies a standard signal by a filter coefficient to generate a control signal. Based on a reference signal and an error signal, the filter coefficient update unit updates the filter coefficient so as to minimize the error signal. The step size determiner sets a step size parameter indicating an update amount of the filter coefficient. The filter coefficient update unit sets a step size adjustment coefficient for adjusting the step size parameter based on an audio information feature amount and a change of the control signal.

Abstract: An active noise reduction device includes a standard signal generator, adaptive filters, a control sound emitter, and an error signal detector. The standard signal generator generates a standard signal including harmonics of a fundamental frequency correlated with the control target sound. The adaptive filters each generates corresponding one of harmonic components of a control signal based on the standard signal. The adaptive filters each is for corresponding one of the harmonics. The control sound emitter emits a control sound based on the control signal. The error signal detector collects residual noise left over after interference between the control target sound and the control sound, and detects an error signal based on the residual noise. Each of the adaptive filters includes a step size determiner. The step size determiner sets the step size parameter based on a frequency variation in the corresponding one of the harmonic components of the standard signal.

Abstract: A fake engine sound control device includes an environment information acquisition unit, a vehicle speed acquisition unit, an engine speed acquisition unit, a fake engine sound generator, and a fake engine sound controller. The environment information acquisition unit acquires environment information. The vehicle speed acquisition unit acquires vehicle speed information. The engine speed acquisition unit acquires rotation speed information. The fake engine sound generator generates a fake engine sound. The fake engine sound controller determines, based on the environment information and the vehicle speed information, whether leading to a target vehicle speed is required, the target vehicle speed being different from the vehicle speed indicated by the vehicle speed information, and controls, when leading to the target vehicle speed is required, the fake engine sound generator based on the target vehicle speed and the rotation speed information.