Electrical audio signal processing systems and devices – Binaural and stereophonic – Pseudo stereophonic
Reexamination Certificate
2000-08-16
2003-08-19
Mei, Xu (Department: 2644)
Electrical audio signal processing systems and devices
Binaural and stereophonic
Pseudo stereophonic
C381S019000, C381S026000
Reexamination Certificate
active
06608903
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of The Invention
The present invention relates to a sound field reproducing method of reproducing an arbitrary sound field such as a concert hall, in another space, and also relates to an apparatus for implementing the method. According to the present invention, sound differences due to performance conditions such as directional properties of a sound source such as a musical instrument and the direction of a performer can be reproduced, thereby enabling a sound field to be reproduced with higher presence.
The present application is based on Japanese Patent Application Nos. Hei. 11-230437 and Hei. 11-265966, which are incorporated herein by reference.
2. Description of the Related Art
A related technique of reproducing of an arbitrary sound field such as a concert hall, in a listening room, a laboratory, or the like will be described. As shown in
FIG. 2
, a sound source S is set on, for example, a stage
12
in a sound field
10
as a concert hall which is to be reproduced, and a sound receiving point R is set in audience seats
14
or the like. As shown in
FIG. 3
, the space surrounding the sound receiving point R is divided into sound receiving element regions R
1
, R
2
, Rj, . . . , and Rm of an appropriate solid angle in which the sound receiving point R is centered. In the example of
FIG. 3
, the horizontal plane is divided into eight regions, and the obliquely upper area into four regions. In total, the space is divided into twelve regions (m=12). As shown in
FIG. 4
(the sound receiving element regions R
1
to Rm in
FIGS. 4 and 6
diagrammatically show the manner of the division in FIG.
3
), an omnidirectional sound source is used as the sound source S. A sound which is radiated from the sound source S, passes through the sound field
10
, and then reaches the sound receiving point R is measured by a directional microphone or calculated for each of directions. On the basis of results of the measurements or calculations, an impulse response when the sound radiated from the sound source S passes through the sound field
10
, enters one of the sound receiving element regions R
1
to Rm, and then reaches the sound receiving point R is obtained for each of the sound receiving element regions R
1
to Rm.
FIG. 5
shows the configuration of a system for reproducing the sound field
10
in an arbitrary real space on the basis of the obtained impulse responses hl to hm respectively for the sound receiving element regions R
1
to Rm. In an arbitrary real space
16
such as a listening room or a laboratory, loudspeakers SP
1
to SPm are placed around a real sound receiving point Rr (usually, a center portion of a plane in the space
16
) where a listener or a test subject listens the sound, and in directions corresponding to the sound receiving element regions R
1
to Rm (FIG.
3
), respectively (in
FIG. 5
, the positions where the loudspeakers SP
1
to SPm are placed are diagrammatically shown in accordance with the manner of showing the sound receiving element regions R
1
to Rm in FIG.
4
). Right and left or two-channel sound signals which are played back from a sound source apparatus 18 such as a DAT (i.e., Digital Audio Tape recorder) or a CD (i.e., Compact Disc) player are combined into one channel signal and then input into FIR filters (convolution operating units)
20
-
1
to
20
-m via an head amplifier
19
. In the FIR filters
20
-
1
to
20
-m, the obtained impulse responses hl to hm are preset as parameters of a convolution operation, respectively. The one-channel sound signal is subjected to a convolution operation in each of the FIR filters
20
-
1
to
20
-m, and sound signals (reflected sound signals) respectively for the directions corresponding to the sound receiving element regions R
1
to Rm are produced. The produced sound signals are amplified by amplifiers
22
-
1
to
22
-m, and then played back by the corresponding loudspeakers SP
1
to SPm, respectively. The sound signals which are played back in the form of right and left or two-channel sounds from the sound source apparatus
18
are additionally played back as they are as direct sounds at front right and left positions with respect to the sound receiving point Rr. Therefore, the listener at the sound receiving point Rr can enjoy the music in an atmosphere which enables the listener to feel as if the listener is in the audience seats
14
in the sound field
10
of FIG.
2
.
In the above, the state where the music performed on the stage
12
of
FIG. 2
is listened in the audience seats
14
is reproduced has been described. When a state where the music performed on the stage
12
is listened in real time on the stage
12
is reproduced, it is possible to conduct a rehearsal or the like in an atmosphere which enables a performer to feel as if the performer is in the sound field
10
. The reproduction technique will be described. In the sound field
10
of
FIG. 2
, the sound source S on the stage
12
is set also as the sound receiving point R. The space surrounding the sound receiving point R (=the sound source S) is divided into sound receiving element regions R
1
to Rm of an appropriate solid angle in which the sound receiving point R is centered in the same manner as FIG.
3
. As shown in
FIG. 6
, an omnidirectional sound source is used as the sound source S, and a sound which is radiated from the sound source S, passes through the sound field
10
, and then reaches the sound receiving point R (=the sound source S) is measured by a directional microphone or calculated for each of directions. On the basis of results of the measurements or calculations, an impulse response when the sound radiated from the sound source S passes through the sound field
10
, enters one of the sound receiving element regions R1 to Rm, and then reaches the sound receiving point R is obtained for each of the sound receiving element regions R
1
to Rm.
FIG. 7
shows the configuration of a system for reproducing the sound field
10
, in an arbitrary real space on the basis of the obtained impulse responses hl to hm respectively for the sound receiving element regions R
1
to Rm. In an arbitrary real space
16
such as a listening room or a laboratory, a microphone
24
is placed at a position which is, for example, above that where the performer is to give a performance (the real sound source Sr and the real sound receiving point Rr, usually, a center portion of a plane in the space
16
), and loudspeakers SP
1
to SPm are placed around the performing position and in directions corresponding to the sound receiving element regions R
1
to Rm (FIG.
3
), respectively (in
FIG. 7
, the positions where the loudspeakers SP
1
to SPm are placed are diagrammatically shown in accordance with the manner of showing the sound receiving element regions R
1
to Rm in FIG.
6
). A one-channel sound signal (performance signal) which is picked up by the microphone
24
is input into FIR filters (convolution operating units)
20
-
1
to
20
-m via a head amplifier
19
. In the FIR filters
20
-
1
to
20
-m, the obtained impulse responses hl to hm are preset as parameters of a convolution operation, respectively. The one-channel sound signal is subjected to a convolution operation in each of the FIR filters
20
-
1
to
20
-m, and sound signals (reflected sound signals) for the directions corresponding to the sound receiving element regions R
1
to Rm are produced. The produced sound signals are amplified by amplifiers
22
-
1
to
22
-m, and then played back by the corresponding loudspeakers SP
1
to SPm, respectively. Therefore, the performer at the sound source S and the sound receiving point Rr can conduct a rehearsal in an atmosphere which enables the performer to feel as if the performer is on the stage
12
in the sound field
10
of FIG.
2
.
In the sound field reproducing method of the related art, the impulse responses hl to hm respectively for the sound receiving element regions R
1
to Rm which are obtained with assuming that the sound source S is omnidirectional
Miyazaki Hideo
Shimizu Yasushi
Mei Xu
Yamaha Corporation
LandOfFree
Sound field reproducing method and apparatus for the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Sound field reproducing method and apparatus for the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sound field reproducing method and apparatus for the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3107950