Sound reproducing device, earphone device and signal processing device therefor

• US 6,614,912 B1
• Filed: 01/19/1999
• Issued: 09/02/2003
• Est. Priority Date: 01/22/1998
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Yamada, Yuji, Ikeda, Yasuhisa
• Primary Examiner(s): Harvey, Minsun Oh
• Application Number:
  US09/232,634
• Time in Patent Office: 1,687 Days
• Field of Search: 381/303, 381/309, 381/310, 381/74, 381/1
• US Class Current: 381/310
• CPC Class Codes: H04R 2420/07 Applications of wireless loudspeakers or wireless microphones
• CPC Class Codes: H04S 1/005 For headphones
• CPC Class Codes: H04S 1/007 in which the audio signals are in digital form data reduction aspects thereof based on psychoacoustics G10L19/02
• CPC Class Codes: H04S 2400/01 Multi-channel, i.e. more than two input channels, sound reproduction with two speakers wherein the multi-channel information is substantially preserved
• CPC Class Codes: H04S 2420/01 Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD]
• CPC Class Codes: H04S 3/004 For headphones
• CPC Class Codes: H04S 7/304 For headphones

Abstract

A sound reproducing device including a signal processing device including a first signal processing circuit supplied with an input audio signal of at least one channel to convert the input audio signal to a 2-channel audio signal with which an acoustic image is located at a predetermined position when the input audio signal is reproduced substantially by a 2-channel speaker system, and a second signal processing circuit supplied with the 2-channel audio signal to subject the 2-channel audio signal to signal processing which is equivalent to a transfer function of the 2-channel speaker system to both the ears of a listener, thereby converting and outputting the input audio signal to a 2-channel audio signal. Also included is an earphone device including a pair of electro-acoustic transducers supplied with the 2-channel audio signal from the second signal processing circuit, and a detector for detecting movement of the head of the listener, wherein the second signal processing circuit performs the processing corresponding to an alteration of the transfer function in accordance with the output of the detector to control the location position of the acoustic image which is perceived by the listener.

Claims

1. A sound reproducing device comprising:

an earphone device;

a first signal processing device including a first signal processing circuit receiving an input audio signal of four channels and for converting the input audio signal to a first 2-channel audio signal with which a reproduced acoustic image is located at a predetermined position relative to a listener when the first 2-channel audio signal is connected to a first output terminal and reproduced by a 2-channel speaker system

a second signal processing circuit receiving the first 2-channel audio signal and for subjecting the first 2-channel audio signal to signal processing equivalent to transfer functions of a 2-channel speaker system to both ears of a listener listening to the 2-channel speaker system, thereby converting the first 2-channel audio signal into a second 2-channel audio signal connected to a second output terminal, said second processing device processing the first 2-channel audio signal so that when the second 2-channel audio signal is reproduced over said earphone device connected to said second output terminal a reproduced acoustic image is located outside the head of a listener wearing the earphone device; and

said earphone device including a pair of electroacoustic transducing means receiving the second 2-channel audio signal from said second signal processing circuit and including detection means for detecting a movement of the head of the listener wearing the earphone device, wherein said second signal processing circuit performs processing corresponding to an alteration of the transfer functions in accordance with the output of said detection means to control the location of the acoustic image perceived by the listener using the earphone device.

2. The sound reproducing device as claimed in claim 1, wherein said earphone device includes means for integrally forming said second signal processing circuit, said pair of electro-acoustic transducing means, and said detection means therein.

3. The sound reproducing device as claimed in claim 1, wherein said signal processing device includes a plurality of output terminals the output signal of said first signal processing circuit is output at said plurality of output terminals, and a plurality of earphone devices are connected to said plurality of output terminals.

4. The sound reproducing device as claimed in claim 1, wherein said detection means comprises a piezoelectric vibrational gyro.

5. A sound reproducing device comprising:

a signal processing device including a first signal processing circuit receiving an input audio signal of at least one channel and for converting the input audio signal to a first 2-channel audio signal with which an acoustic image is located at a predetermined position when the first 2-channel audio signal is reproduced by a 2-channel speaker system and a second signal processing circuit receiving the first 2-channel audio signal and for subjecting the first 2-channel audio signal to signal processing equivalent to transfer functions of said 2-channel speaker system to both ears of a listener, thereby converting the first 2-channel audio signal into a second 2-channel audio signal; and

an earphone device including a third signal processing circuit receiving the second 2-channel audio signals from said second signal processing circuit, a pair of electro-acoustic transducing means receiving an output signal from said third signal processing circuit, and detection means for detecting movement of the listener'"'"'s head, wherein said third signal processing circuit performs processing corresponding to an alteration of the transfer functions in accordance with an output of said detection means for controlling the position of the acoustic image perceived by the listener.

6. The sound reproducing device as claimed in claim 5, wherein said earphone device includes means for integrally forming said third signal processing circuit, said pair of electro-acoustic transducing means, and said detection means therein.

7. The sound reproducing device as claimed in claim 5, wherein said signal processing device includes a plurality of output terminals, the output signal of said second signal processing circuit is output at said plurality of output terminals, and a plurality of earphone devices are connected to said plurality of output terminals.

8. The sound reproducing device as claimed in claim 5, wherein said detection means comprises a piezoelectric vibrational gyro.

9. An earphone device used in combination with a signal processing device supplied with an input audio signal of four channels and for converting the input audio signal to a first 2-channel audio signal with which a reproduced acoustic image is located at a predetermined position relative to a listener when the first 2-channel audio signal is reproduced by a 2-channel speaker system and for subjecting the first 2-channel audio signal to signal processing equivalent to transfer functions of said 2-channel speaker system to both ears of a listener listening to the 2-channel speaker system, the earphone device comprising:

a signal processing circuit receiving the first 2-channel audio signal from said signal processing device for subjecting the first 2-channel to signal processing equivalent to transfer functions of a 2-channel speaker system to both ears of a listener listening to the 2-channel speaker system, thereby converting the first 2-channel audio signal into a second 2-channel audio signal;

a pair of headphones supplied with said second 2-channel audio signal output from said signal processing circuit, wherein said signal processing circuit processes said first 2-channel audio signal so that when the second 2-channel audio signal is reproduced over said pair of headphones a reproduced acoustic image is located outside the head of a listener wearing the pair of headphones; and

detection means for detecting movement of the head of the listener wearing said pair of headphones, wherein said signal processing circuit performs processing corresponding to an alteration of the transfer functions on the second 2-channel audio signal in accordance with an output of said detection means for controlling the position of the acoustic image perceived by the listener wearing the pair of headphones.

10. The earphone device as claimed in claim 9, wherein said detection means comprises a piezoelectric vibrational gyro.