Automotive audio reproducing apparatus

• US 20020034308A1
• Filed: 09/12/2001
• Published: 03/21/2002
• Est. Priority Date: 09/14/2000
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Usui, Junichi, Itabashi, Tetsunori
• Granted Patent: US 6,501,843 B2
• Time in Patent Office: Days
• US Class Current: 381/17
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04R 5/02 Spatial or constructional arrangements of loudspeakers
• CPC Class Codes: H04S 1/002 Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution control circuits for electronic adaptation of the sound field H04S7/30

Abstract

An automotive audio reproducing apparatus according to the present invention comprises: a sound image position correction circuit 52 for converting a left-channel input digital audio signal XL(Z) and a right-channel input digital audio signal XR(Z) into a digital audio signal YL(Z) and a digital audio signal YR(Z), respectively, for output expressed by:

YL(Z)·GLL(Z)+YR(Z)·GLR(Z)=XL(Z)·FLL(Z)+XR(Z)·FLR(Z)

YR(Z)·GLL(Z)+YL(Z)·GLR(Z)=XR(Z)·FLL(Z)+XL(Z)·FLR(Z)

where FLL(Z) to GLR(Z) are given head related transfer functions; a depth correction circuit 53 for adding reflected sound signals to the signals YL(Z) and YR(Z), respectively; a D/A converter circuit 6 for subjecting output signals of the correction circuit 53 to D/A conversion; and a level control circuit 522 for controlling level of a difference signal in the sound image position correction circuit 52; whereby analog audio signals outputted from the D/A converter circuit 6 are supplied to a left-channel speaker and a right-channel speaker, respectively.

Claims

1. An automotive audio reproducing apparatus comprising:

a sound image position correction circuit for converting a left-channel input digital audio signal XL(Z) and a right-channel input digital audio signal XR(Z) into a digital audio signal YL(Z) and a digital audio signal YR(Z), respectively, for output expressed by;

YL(Z)·

GLL(Z)+YR(Z)·

GLR(Z)=XL(Z)·

FLL(Z)+XR(Z)·

FLR(Z)YR(Z)·

GLL(Z)+YL(Z)·

GLR(Z)=XR(Z)·

FLL(Z)+XL(Z)·

FLR(Z)

 

where

FLL(Z) is a head related transfer function from a first left-channel speaker and a first right-channel speaker located in front of a listener in a passenger compartment to a left ear and a right ear of said listener, respectively;

FLR(Z) is a head related transfer function from said first left-channel speaker and said first right-channel speaker to the right ear and the left ear of said listener, respectively;

GLL(Z) is a head related transfer function from a second left-channel speaker and a second right-channel speaker located in lower front of said listener to the left ear and the right ear of said listener, respectively; and

GLR(Z) is a head related transfer function from said second left-channel speaker and said second right-channel speaker to the right ear and the left ear of said listener, respectively;

a reflected sound signal generating circuit for generating reflected sound signals by delaying said output signals YL(Z) and YR(Z), respectively;

a pair of adding circuits for adding said reflected sound signals to said output signals YL(Z) and YR(Z), respectively; and

a D/A converter circuit for being supplied with output signals of the pair of adding circuits;

wherein when

Hp(Z)=(FLL(Z)+FLR(Z))/(GLL(Z)+GLR(Z))Hm(Z)=(FLL(Z)−

FLR(Z))/(GLL(Z)−

GLR(Z)),

 

said sound image position correction circuit includes;

a first adding circuit and a first subtracting circuit for subjecting said input digital audio signals XL(Z) and XR(Z) to addition and subtraction, respectively;

a first digital filter and a second digital filter having transfer characteristics of said Hp(Z) and said Hm(Z) for being supplied with output signals of said first adding circuit and said first subtracting circuit, respectively;

a second adding circuit and a second subtracting circuit for subjecting output signals of the first digital filter and the second digital filter to addition and subtraction and thereby generating said output signals YL(Z) and YR(Z), respectively; and

a level control circuit connected in series with said second digital filter in a signal line between said first subtracting circuit and said second adding circuit and said second subtracting circuit;

whereby said level control circuit controls level of a difference signal supplied to said second adding circuit and said second subtracting circuit; and

analog signals outputted from said D/A converter circuit are supplied to said second left-channel speaker and said second right-channel speaker, respectively.

2. An automotive audio reproducing apparatus as claimed in claim 1,

wherein delay time or level of said reflected sound signals supplied to said pair of adding circuits is controlled.

3. An automotive audio reproducing apparatus as claimed in claim 2, further including a correction circuit for correcting frequency characteristics of said output signals YL(Z) and YR(Z) that become said reflected sound signals.

4. An automotive audio reproducing apparatus as claimed in claim 2 or claim 3,

wherein a frequency characteristic correction circuit is provided in a stage preceding said sound image position correction circuit.

5. An automotive audio reproducing apparatus as claimed in claims 1 to 4,

wherein at least said sound image position correction circuit, said reflected sound signal generating circuit, and said pair of adding circuits are formed by a DSP.