Abstract: A speaker that is configured to emit ultrasonic waves includes an ultrasonic emission unit, a reflector, and a louver unit. The ultrasonic emission unit is configured to emit ultrasonic waves in an emission direction. The reflector is disposed at a side of the ultrasonic emission unit from which the ultrasonic waves are emitted. The reflector is configured to reflect the ultrasonic waves emitted from the ultrasonic emission unit in a predetermined direction. The louver unit is disposed between the ultrasonic emission unit and the reflector. The louver unit includes slits formed therein in a manner such that the slits do not change a direction of the ultrasonic waves between the ultrasonic emission unit and the reflector, and do not change a direction of the ultrasonic waves reflected by the reflector. The louver unit is configured to inhibit entry of foreign matter into the ultrasonic emission unit.

Abstract: A noise canceling adaptive filter outputs, from a front seat speaker, a noise canceling sound generated by applying a transfer function X(z) adapted by an adaptive operation using an output of a front seat microphone as an error to an output sound of a sound source apparatus. An output of the front seat microphone is added to an output of an audio feedback canceling filter by a second adder, added to an output sound of the sound source apparatus by a third adder, and output from a rear seat speaker. The audio feedback canceling filter applies a transfer function X?(z) and a transfer function C{circumflex over (?)}(z) on an output of the second adder and outputs a resultant. The transfer function C{circumflex over (?)}(z) corresponds to a transfer function C(z) from the front seat speaker to the front seat microphone. In synchronization control, the transfer function X(z) is set as the transfer function X?(z).

Abstract: A speaker includes a yoke configured to form a magnetic circuit, a first magnet provided in a fixed manner, a voice coil provided in a gap through which a magnetic flux of the magnetic circuit is configured to pass, a diaphragm connected to the voice coil and configured to vibrate with the voice coil, a second magnet provided on a diaphragm unit including the voice coil and the diaphragm, and a magnetic sensor provided at a position through which both of a first magnetic flux generated by the first magnet and a second magnetic flux generated by the second magnet are configured to pass, wherein a direction of the first magnetic flux and a direction of the second magnetic flux are different from each other.

Abstract: In a speaker distortion correction device, an input signal passes through a nonlinear-portion correction filter and is input into a linear inverse filter. An output signal from the linear inverse filter is output into a speaker through an amplifier. For the nonlinear-portion correction filter, transfer characteristics (filter coefficients) are set that eliminate distortion due to nonlinear characteristics of the speaker. With a difference, as an error, between vibration of the speaker without distortion relative to an input signal and vibration of a vibration system of the speaker measured by a vibration measurement unit, an adaptive-algorithm execution unit performs an adaptive operation that adaptively updates filter coefficients of the linear inverse filter.

Abstract: A right seat processing unit includes, assuming that a voice of a user in a right front seat is a right front seat voice, a filter HR that converts the right front seat voice being output from a left front seat microphone disposed on a headrest of a left front seat into the right front seat voice collected by a right seat virtual microphone that is a virtual microphone located on a left side of a headrest of the right front seat, a delay unit Z-TR that delays and outputs an output from a right front seat microphone located on a right side of the headrest of the right front seat, a filter WRA that extracts the right front seat voice being output from the filter HR, a filter WRB that extracts the right front seat voice being output from the delay unit Z-TR, and a right adder that adds outputs of the filter WRA and the filter WRB and outputs an added output as a right front seat speech voice signal.

Abstract: A surround sound entertainment system configured to determine a microphone position relative to a first loudspeaker, the system comprising: first loudspeaker interface configured to send first acoustic signals to first loudspeaker; second loudspeaker interface configured to send second acoustic signals to second loudspeaker; microphone interface configured to receive microphone data from microphone; acoustic processor configured to generate acoustic signal output to each of first and second loudspeakers; and non-transitory memory comprising instructions executable by the acoustic processor, instructions when executed by acoustic processor, cause system to: receive microphone data via microphone interface; determine, using microphone data, time delay between reproduction of first acoustic signals on first loudspeaker and reception of corresponding sound by microphone; determine, using time delay, position of microphone relative to first loudspeaker; and determine, based on position of microphone relative to fi

Abstract: A signal e(z) obtained by subtracting echo-canceling sound from an output of a second microphone is used as an error of an echo cancellation adaptive filter and a noise cancellation adaptive filter, and an output of a first sound source device is added to the signal e(z) and output from a first speaker. The echo cancellation adaptive filter generates echo-canceling sound from an addition signal of the output of the second sound source device and the output of the first microphone such that the signal e(z) is minimized. The noise cancellation adaptive filter generates the noise-canceling sound from the output of the first sound source device such that the signal e(z) is minimized, and outputs the noise-canceling sound from the second speaker.

Abstract: An active noise control system includes an error adder that generates an error signal by adding an output of a left-seat left microphone and an output of a left-seat right microphone, an adaptive filter that generates a noise canceling sound from a reference signal by performing an adaptive operation using the reference signal and the error signal, a left channel gain adjustment section that adjusts a gain of the noise canceling sound to be output to a left-seat left speaker, and a right channel gain adjustment section that adjusts a gain of the noise canceling sound to be output to the left-seat right speaker. A ratio between the gains of the left channel gain adjustment section and the right channel gain adjustment section matches a ratio between loudness levels of noise transmitted to the output of the left-seat left microphone and the output of the left-seat right microphone.

Abstract: An assist band is set to a standard band when there is no large road noise, and is set to a treble band not including a low frequency band but including a high frequency band as compared with the standard band when there is a large road noise. In audio data of a front seat microphone, components outside the assist band are cut by an IIR filter, downsampled by a downsampling unit to a sampling frequency that is twice the upper limit of the assist band, processed by an echo canceller and a howling canceller, upsampled by an upsampling unit, and output to a rear seat speaker. When there is a large road noise, the operation of the howling canceller is invalidated, and the input is output as it is.

Abstract: A vibrating unit includes a diaphragm and a bobbin, and a voice coil is secured to the bobbin. A detecting unit includes a moving magnet and a magnetic sensor. An annular magnet support is secured to a front edge of the bobbin, and the moving magnet is positioned and secured to the magnet support. The magnetic sensor is secured to a drive supporting unit. The moving magnet is secured to the bobbin, with the magnet support therebetween. This facilitates mounting and positioning of the moving magnet.

Abstract: One form of an audio signal processing apparatus adds a low-frequency sound sensation enhancement signal for enhancing a low-frequency sound sensation of an audio source signal to the audio source signal output by an audio source device, and outputs a resultant signal to a loudspeaker. The audio signal processing apparatus generates the low-frequency sound sensation enhancement signal with a frequency range from f0 to f1 (where f0<f1) by contraction mapping of components in a frequency range lower than f0 of the audio source signal using FIF (Fractal Interpolation Functions) where f0 is a frequency at a lower limit of a reproduction frequency range of the loudspeaker.

Abstract: In some implementations, an output of a first channel of an echo cancellation variable filter having an output of a first microphone output from a second speaker as an input is added to an output of a second microphone. An echo cancellation coefficient updating unit updates the filter coefficient of the first channel so that the error that is the output of a second adder is minimized. Using the output of the second channel that uses the output of a sound source device output from the first speaker as an input and shares the filter coefficient with the first channel as a reference signal, and the output of the second microphone as an error, the noise cancellation coefficient updating unit updates the filter coefficient of the noise cancellation variable filter that generates a noise-canceling sound to be output from the output of the sound source device to the second speaker.

Abstract: A noise canceling adaptive filter outputs, from a front seat speaker, a noise canceling sound generated by applying a transfer function X(z) adapted by an adaptive operation using an output of a front seat microphone as an error to an output sound of a sound source apparatus. An output of the front seat microphone is added to an output of an audio feedback canceling filter by a second adder, added to an output sound of the sound source apparatus by a third adder, and output from a rear seat speaker. The audio feedback canceling filter applies a transfer function X?(z) and a transfer function C^(z) on an output of the second adder and outputs a resultant. The transfer function C^(z) corresponds to a transfer function C(z) from the front seat speaker to the front seat microphone. In synchronization control, the transfer function X(z) is set as the transfer function X?(z).

Abstract: A seamless steel pipe has a t/Dout of 0.05 to 0.40, where t is a wall thickness (mm) of the seamless steel pipe, and Dout is an outside diameter (mm) of the seamless steel pipe. The seamless steel pipe has a maximum depth dmax (mm)?0.350 mm for defects in an inner surface of the steel pipe on a cross section perpendicular to a pipe axis. The seamless steel pipe has an average defect depth dave (mm)?0.200 mm for defects having a depth of 0.050 mm or more in the inner surface of the steel pipe. The seamless steel pipe, per millimeter of an inner circumferential length of the pipe, has at most 30 defects having a depth of 0.050 mm or more in the inner surface of the steel pipe.

Abstract: A magnetic angle sensor outputs a component Vs in a Y direction where a vibration system of a synthetic vector of a magnetic vector of a magnetic circuit of a speaker and a magnetic vector of a displacement detection magnet fixed on the vibration system and a component Vc in an X direction orthogonal to the Y direction. A test signal is applied to the speaker, and collection of (Vs, Vc) and a measurement of a Y-direction displacement of the vibration system by a displacement meter are performed. A conversion equation “z=a1xVs+a2xVc” for the first principle component is obtained by principle component analysis on collected (Vs, Vc), and a conversion equation “y=b1xz2+b2xz+b3” for conversion to a displacement y is obtained by polynomial regression on the Y-direction displacement y of the displacement detection magnet obtained from a measurement value of the displacement meter and z calculated from collected (Vs, Vc).

Abstract: Adaptive operations of a first noise control system and a second noise control system may include a speaker that outputs noise cancellation sound, a microphone that detects an error signal, an auxiliary filter that generates, from a noise signal, a correction signal that corrects the error signal so that a difference in a position between the microphone and a noise cancellation position is compensated, and an adaptive filter that performs an adaptive operation using the corrected error signal to generate the noise cancellation sound from the noise signal are alternately performed. A transfer function learned in a state in which the second noise control system is stopped is set in the auxiliary filter of the first noise control system, and a transfer function learned in a state in which the adaptive operation of the first noise control system is stopped is set in the auxiliary filter of the second noise control system.

Abstract: In a speaker distortion correction device, an input signal passes through a nonlinear-portion correction filter and is input into a linear inverse filter. An output signal from the linear inverse filter is output into a speaker through an amplifier. For the nonlinear-portion correction filter, transfer characteristics (filter coefficients) are set that eliminate distortion due to nonlinear characteristics of the speaker. With a difference, as an error, between vibration of the speaker without distortion relative to an input signal and vibration of a vibration system of the speaker measured by a vibration measurement unit, an adaptive-algorithm execution unit performs an adaptive operation that adaptively updates filter coefficients of the linear inverse filter.

Abstract: A right seat processing unit includes, assuming that a voice of a user in a right front seat is a right front seat voice, a filter HR that converts the right front seat voice being output from a left front seat microphone disposed on a headrest of a left front seat into the right front seat voice collected by a right seat virtual microphone that is a virtual microphone located on a left side of a headrest of the right front seat, a delay unit Z-TR that delays and outputs an output from a right front seat microphone located on a right side of the headrest of the right front seat, a filter VVRA that extracts the right front seat voice being output from the filter HR, a filter WRB that extracts the right front seat voice being output from the delay unit Z-TR, and a right adder that adds outputs of the filter WRA and the filter WRB and outputs an added output as a right front seat speech voice signal.

Abstract: A first cancellation signal output from a first speaker cancels noise at a first cancellation point, which is a typical position of the right ear of a user, together with a second cancellation signal output from a second speaker. In addition, the second cancellation signal output from the second speaker cancels noise at a second cancellation point, which is a typical position of the left ear of the user, together with the first cancellation signal output from the first speaker. The first speaker and the second speaker are arranged side by side on a second line segment, which passes through the midpoint of a first line segment connecting the first cancellation point and the second cancellation point to each other and is perpendicular to the first line segment, and a range where the relationship between noise and the first cancellation signal and the second cancellation signal is the same as that at the cancellation point is extended.

Abstract: In a first system signal processing unit, a first system auxiliary filter generates a correction signal for correcting an error signal from a noise signal, a first system subtractor subtracts the correction signal from an output of a first microphone to obtain an error signal, an adaptive filter performs an adaptive operation using the error signal to generate a cancel sound output from a first speaker, and a DMS detects a position of a user's ear. When the position of the user's ear moves, the controller stops the adaptive operation, updates the transfer function of the first system auxiliary filter to the transfer function corresponding to the noise cancel position matching the position of the user's ear, gradually changes the transfer function of the adaptive filter to the transfer function corresponding to the matching noise cancel position, and resumes the adaptive operation after the change is completed.