SOUND FIELD REPRODUCING APPARATUS

APPAREIL DE REPRODUCTION DU CHAMP ACOUSTIQUE

English Abstract

ABSTRACT OF THE DISCLOSURE
A sound field reproduction apparatus comprises a
reflectional sound signal generating circuits for
generating quasi-reflectional sound signals by summing a
plurality of delay signals obtained by delaying source
signals in order, and amplifiers for amplifying the level
of quasi-reflectional sound signals. The apparatus is
characterized by a signal selecting and repeating device
for alternatively repeating either the quasi-reflectional
sound signals and the source signals, or source signals
different from the above-described source signals. With
this feature, it becomes possible to reproduce source
signals other than the source signals for use in the
sound field reproduction.
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Claims

The embodiments of the invention in which an
exclusive property or privilege is claimed, are defined as
follows:
1. A sound reproduction system comprising:
signal input means for receiving a plurality of
input signals from a plurality of signal sources;
first selecting means for selectively transmitting
at least one input signal from one of said plurality of
signal sources received by said input means;
second selecting means for selectively transmitting
at least one input signal from one of said plurality of
signal sources received by said input means;
first amplifying means for amplifying said at least
one input signal selected by said first selecting means and
producing output signals;
second amplifying means for amplifying said at
least one input signal selected by said second selecting
means and producing output signals;
a first set of speakers placed in a first room;
a second set of speakers placed in a second room;
first supply means for supplying said output
signals of said first amplifying means to said first set of
speakers; and
second supply means for supplying said output
signals of said second amplifying means to said second set
of speakers.
2. The sound reproduction system of claim 1 further
comprising:
reflectional sound signal generating means
connected to said first selecting means for generating as
output first and second set of reflectional sound signals
from said at least one input signal selected by said first
selecting means;
first signal switching means having a first switch
position for supplying said first set of reflectional sound
signals generated by said reflectional sound signal
generating means to said first amplifying means and a
second switch position for supplying said at least one

11
input signal of said one of said plurality of signal
sources received by said input means to said first
amplifying means;
second signal switching means having a first switch
position for supplying said second set of reflectional
sound signals generated by said reflectional sound signal
generating means to said second amplifying means and a
second switch position for supplying said at least one
input signal selected by said second selecting means to
said second amplifying means;
a third set of speakers placed in said first room;
and
third signal switching means connected to said
second amplifying means having a first switch position for
supplying said output signals of said second amplifying
means to said third set of speakers and a second switch
position for supplying said output signals of said second
amplifying means to said second set of speakers.
3. The sound reproduction system of claim 2, further
comprising interlocking means, responsive to an operation
of said second selecting means, for causing said second and
third signal switching means to select their respective
second switch positions when an input signal from a
predetermined one of said plurality of signal sources is
selected by said second selecting means.
4. A sound reproduction system comprising:
signal input means for receiving a plurality of
input signals to be reproduced;
first source signal selecting circuit for selecting
for output one of said input signals received by said
signal input means;
signal selecting means having a first input
terminal for receiving the output of the first source
signal selecting circuit and a second input terminal, and
selecting for output one of said input signals applied to
said first or second input terminals thereof;
second source signal selecting circuit for
selecting for output one of said plurality of input

12
signals;
two-channel amplifier means for amplifying the
output of said signal selecting means;
first and second pairs of speakers placed in a
first room where it is desired to produce concert hall
sound, said first pair of speakers being connected to said
two-channel amplifier means;
a third pair of speakers placed in a second room
where it is desired to produce regular sound:
sound field reproducing means comprising:
reflectional sound signal generating means
receiving as input the output of said first source signal
selecting circuit and generating as output first, second,
third and fourth reflectional sound signals by delaying the
input signal to produce delay signals and adding the delay
signals in sequence, the first and second reflectional
sound signals of said reflectional sound signal generating
means being applied to the second input terminal of said
signal selection means;
first relay switch having a first input terminal
receiving the output of the second source signal selecting
circuit and a second input terminal receiving the third
reflectional sound signal of said reflectional sound signal
generating means, said first relay switch supplying as
output one of the signals applied to the first or second
input terminal thereof;
second relay switch having a first terminal
receiving the output of said second source signal selecting
circuit and a second input terminal receiving the fourth
reflectional sound signal of said reflectional sound signal
generating means, said second relay switch means supplying
as output one of the signals applied to the first or second
input terminal thereof;
first amplifier means connected to the output of
said first relay switch for amplifying the output thereof;
second amplifier means connected to the output of
said second relay switch for amplifying the output thereof;
third relay switch means for receiving the output

13
of the first amplifier and connecting the output of the
first amplifier to either a first speaker of said second
pair of speakers in the first room or a first speaker of
said third pair of speakers in the second room;
fourth relay switch means for receiving the output
of the second amplifier and connecting the output of the
second amplifier to either a second speaker of said second
pair of speakers in the first room or a second speaker of
said third pair of speakers in the second room; and
switch control means for controlling the first,
second, third and fourth relay switch means, so that when
it is desired to listen to concert hall sound of one of
said plurality of input signals, the first and second relay
switch means are caused to select the signals on their
respective first input terminals, the third and fourth
relay switch means are caused to connect the outputs of the
first and second amplifier means, respectively, to the
first and second speakers of the second pair of speakers in
the first room, and the signal selecting means is caused to
select the signal on the second input terminal thereof to
connected the first and second relectional sound signals to
the two channel amplifier means, and when it is desired to
listen to normal sound reproduction in the second room, the
first and second relay switch means are caused to select
the signals on their respective second input terminals, the
third and fourth relay switch means are caused to connect
the outputs of the first and second amplifier means,
respectively, to the first and second speakers of the third
pair of speakers in the second room.
5. The sound reproduction system of claim 4 wherein
the second source signal selecting circuit generates a
command signal upon operation, said command signal
indicative of the desire to listen to normal sound in the
second room through the third pair of speakers and being
supplied to for controlling each of said first, second,
third and fourth relay switch means.

14
6. The sound reproduction system of claim 4 wherein
the signal selecting means is operative to supply the
output of the first source signal selecting circuit to the
two-channel amplifying means so that normal sound
reproduction can be provided through the first pair of
speakers in the first room when normal sound reproduction
is provided in the second room.
7. A sound reproduction system comprising:
first and second pair of speakers placed in a first
room where it is desired to listen to concert sound
reproduction;
a third pair of speakers placed in a second room
where it is desired to listen to normal sound reproduction;
signal input means for receiving an input signal to
be reproduced;
reflectional sound signal generating means for
generating reflectional sound signals by producing delay
signals of said input signal and adding the delay signals
in sequence:
amplifying means for amplifying the level of the
reflectional sound signals or the input signal and
generating an output representative thereof;
first signal selecting means for supplying either
the input signal or the reflectional sound signals as input
to the amplifying means;
second signal selecting means for connecting the
output of the amplifying means to the second pair of
speakers or to said third pair of speakers; and
control means for controlling the first and second
signal selecting means so that when it is desired to listen
to concert hall sound reproduction of the input signal in
the first room, the first signal selecting means is caused
to supply the reflectional sound signals as input to the
amplifying means and the second signal selecting means is
caused to connect the output of the amplifying means to the
second pair of speakers, and then it is desired to listen
to normal sound reproduction in the second room, the first

signal selecting means is caused to supply the input
signals as input to the amplifying means and the second
signals selecting means is caused to connect the output of
the amplifying means to third pair of speakers in the
second room.

Description

'1 3 ~
SOUND FIELD REPRODUCING APPARATUS
BACKGROUND OF THE_INVENTION
1. Field of the Invention
05 The present invention relates to a sound field
reproducing apparatus.
2. DescriPtion of ~ark~round Information
Sound field reproduction apparatuses are generally
structured to gener~te quasi-reflectional sound signals
from input signals, and to drive a plurality of sub-
speaker systems for generating quasi-reflectional sounds.
Consequently those apparatuses have complex circuit
constructions, and are relatively expensive. ~ccordingly
there are demands that a sound field reproduction
apparatus is utilized effectively also when the sound
field reproduction is not ef~ected by the apparatus.
OBJECT AND SUMMARY OF ~HE INVEN~ION
An object of the present invention is to provide a
sound field reproduction apparatus which is capable of
the sound field reproduction and also another function.
In order to attain the above object, a sound field
reproduction apparatus according to the preæent in~ention
comprises a reflectional sound signal generating means
for generating quasi-reflectional sound signals by
summing a plurality of delay signals obtained by delaying

~32:~7~$
source signals in order, and amplifiers for amplifying
the level of quasi-reflectional sound signals, and the
apparatus further includes signal selecting and repeating
means for al~ernatively repeating either the quasi-
05 reflectional sound signals and the source signals, oxsource signals different from the above-described source
signals.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a block diagram showing an example of
conventional sound field reproducing apparatus; and
Figure 2 is a block diagram showing an embodiment of
the sound ~ield reproducing apparatus according to the
present invention.
DETAILED DESCRIPTION OF A PREFERRED ENBODIMENT
Before entering into the explanation of the
embodiment of the present invention an example of
conventional sound field reproducing apparatus will be
explained with reference to Figure 1.
In Figure 1, signals from sources 1 through 3 are
supplied to a selector 1. For, example, the source 1 is a
video disc player and stereophonic signals are supplied
from the video disc player. The source 2 is a CD player
and also stereophonic signals are supplied from the CD
player. The third stereophonic signals are supplied from
an FM tuner servi~g as the source 3. ~urth~r, the signals

7 ~
from these sources may be monaural signal6.
In accordance with the designation of an operator,
the selector 1 selects signals from one of sources 1
through 3 and supplies them to a two-channel amplifier 2
05 and a surround circuit 3. The two-channel amplifier 2 is
made up of two separa~e amplifiers for respectively
amplifying the left and right signals of source signals,
i.e. signals from the selected source. The left and right
signals amplified in power~are supplied to main speaker
systems 4a and 4b which are symmetrically placed a little
to the centert at a front end of a listening-room.
The surround circuit 3 is made up of three or more
reflectional sound circuits each of which includes a
plurality of series circuits connected in parallel with
each other, each of the series circuit being made up of a
delay circuit for delaying the source signal a~d an
amplifier for amplifying the output signal o~ the delay
circuit. As an example, the surround cir~uit 3 shown in
the figure is made up of three reflectional sound
circuits.~The reflectional soun~ cixcuits ye~erate quasi-
reflectional sound signals. Parameters used in the
reflectional sound circuits, such as the de~lay ~Lme of
the delay circuits and the amplification factor of the
amplifiers of each reflectional sound circuit, are
determined by a microprocessor (not shown) in the

>~
surround circuit 3. The microprocessor is configured to
read-out data, which corresponds to a sound field to be
reproducedl from a ROM. The quasi-reflectional sound
signal outputs of first and second reflectional sound
05 circuits are respectively supplied to front amplifiers 5
and 6, amplified in power by the front amplifiers 5 and
6, and supplied to front sub-~peaker system~ 4c and 4d
which are placed at the left and right sides o~ the front
end of the listening room.
The quasi-reflectional sound signal outputs of the
third and fourth reflectional sound circuits are
respectively supplied to rear amplifiers 7 and 8 and
supplied to rear sub speaker systems 4e and 4f which are
arranged on the left and riyht sides of a rear end of the
listening room 4. The surround circuit 3 and the
amplifiers 5 and 8 constitute the sound field repxoducing
circuit 10.
In this way, at the time of the playback of a two-
channel stereo, a concert-hall presence is obtained in
the listening room 4 by adding the quasi-reflectional
sounds by the front and rear sub-spea~er systems.
This sound field ~eproduction.apparatus driving a
plurality of sub-speaker systems for generating quasi-
reflectional sounds is relatively expensive. Therefore,
~5 as mentioned before, it is desirable that the apparatus

3 ~7~
is utilized eff~ctively also when the sound fi~ld
reproduction is not performed.
An embodiment of the sound ~ield reproducing
apparatus will ba described with reference to Figure 2.
05 Like reference numerals are used to denote like
parts or corresponding elements in Figures 1 and 2, and
the explanation of elament the same as the part~ shown in
Figure 1 will not be repeated.
In the circuit arrangement shown in Figure 2, with
the operation of a signal selecting circuit 2a, the two-
channel amplifier 2 is commonly used in both of the case
where the surround reproduction is performed and the case
where the surround reproduction is not performed. With
this construction, the front amplifiers 5 and 6 are
eliminated in this arrangement, to save ~he cost.
Furthermore, the selector 20 is provided independently of
the selec~or 1, and signalæ from sources 1 through :3 are
also supplied to input terminals of the selector 20. The
source signals selected by the selector 20 are
respectively supplied to one input terminal of each of
relay switches 22 and 23 through an input terminal 21a of
the-sound field reproducing apparatus 21. To the other
input terminal of each of the relay switches 22 and 23,
~uasi-rear reflectional sound signals are respectively
supplied from the third and fourth reflectional sound

circuit of the surrvund circuit 3. The relay switches 22
and 23 are configured to ~elect one of tw~ input ~ignals
and supply it to the rear amplifiers 7 and 8
respectively, in response to the closing comrnand signal
05 supplied from a switch 24. The output signal of the r~lay
switch 7 amplified in power by the rear amplifier 7 is
supplied to a common input terminal of a relay switch 25
which operates in response to the above-mentioned closing
command signal. The relay~switch 25 is configured to
supply the amplified output signal to the rear speaker 4e
in the listening room 4 through an outpu~ terminal 21b
when the closing colmnand signal is no~ present. On the
other hand, when the closing command signal is present
the relay switch 25 supplies the amplified output signal
to a speaker 27a placed in another room (or in other
words, acoustic space) through an output terminal 21c.
On the other hand, the output signal of the relay
switch 23 which has been amplified by the rear:amplifier
8 is supplied to the a common input terminal of a relay
switch 26. When the above-mentioned closing command
signal is not present, the relay switch 26 supplies the
amplified output signal to the rear speaker in the
listening room 4 through an output terminal 21d, and
supplies it to a speaker 27b in the room 27 through an
output terminal 21e when the above-mentioned closing

p~ ~ ~
command signal is not present.
With this arrangement, when the ~ound field is to be
reproduced in the listening room 4, the output signals of
the surround circuit 3 are repeated to the two channel
05 ~mplifier 2 through the signal selecting circuit 2a, and
the switch 24 is operated to its open state. A~ a result,
the quasi-reflectional sound signals from the surround
circuit 3 are selected by the relay switches 22 and 23,
and amplified by the rear~amplifiers 7 and 8. This quasi-
reflectional sound signals after having been amplifiedare supplied to the rear speakers 4e and 4f in the
listening room 4 through the relay switches 25 and 26 SQ
~hat the sound field is reproduced as with the
conventional apparatus.
lS On the other hand, when the sound from the signal
source is to be listened in the room 27, the switch 24 ~s
closed so that the closing command signal is supplied to
the relay switches 22, 23, 25 a~d 26. When these relay
switches are switched overr the source signals ~rom the
source selected by the listener at the selector 20 are
amplified in power by the rear amplifiers 7 and 8, and
respectively supplied to the speakers 27a-and 27b placed
in the room 27. Therefore, a sound from a desired source
can be listened in the room 27. In this state, it is
possible to reproduce ~he sound field in the listening

room 4 by using the speakers 4a and 4b.
In this way, the amplifiers of the sound field
reproducing apparatus are used both for the power
amplification of the output signals of the surround
05 circuit 3 and the ampli~ication of the source signals.
~his means that the sound field reproducing apparatus can
be versatilely utilized.
In addition, as illustrated by the dashed line in
the Figure 2, the apparatus may be configured th~t the
switch 24 is interconnected with the selector 20/ 50 that
it is automatically switched ~hen source signals of any
one source are selected by the selector 20.
Furthermore, it is also possible to arrange the
apparatus such that the two channel amplifier 2 amplifies
selectively either of the source signals or quasi-
reflectional sound signals, as with the rear amplifiers.
Moreo~er~ by adopting an arrangement that the relay
switches 22, ~3, 25 and 26 are operated independently,
the source signals from another source can be reproduced
by the rear sub-~peakers/ for example, when the source
signals from one source is reproduced in the listening
room 4.
As explained in the foregoing, in the case of the
sound field reproducing apparatus according to the
~5 present invention, a signal selecting and repeating means

~g~
is provided between the reflectional sound generating
circuit which derives quasi-xeflectional sound signal6
from the selected souxce signals and amplifiers which
amplify the level of the output signals of the
OS reflectional sound generating circuit, and selected ones
among a plurality of original source signals and the
above-described quasi-reflectional s~und signals are
supplied to the above-described amplifiers. Therefore,
the sound of source signals which are different from
source signals to be used for the reproduction of the
sound field can be listened without using any additîonal
power amplifiers which generally require a high
additional cost.

Representative Drawing