U.S. patent number 3,765,504 [Application Number 05/204,841] was granted by the patent office on 1973-10-16 for speaker apparatus.
This patent grant is currently assigned to Sansui Electric Co., Ltd.. Invention is credited to Ryosuke Itoh.
United States Patent |
3,765,504 |
Itoh |
October 16, 1973 |
SPEAKER APPARATUS
Abstract
A speaker apparatus has a cabinet and at least one speaker unit
secured to the cabinet, and includes at least one board for
reflecting sound irregularly and diffusively into a reproducing
room from the speaker unit.
Inventors: |
Itoh; Ryosuke (Tokyo,
JA) |
Assignee: |
Sansui Electric Co., Ltd.
(Tokyo, JA)
|
Family
ID: |
26451926 |
Appl.
No.: |
05/204,841 |
Filed: |
December 6, 1971 |
Foreign Application Priority Data
|
|
|
|
|
Dec 17, 1970 [JA] |
|
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45/112856 |
Dec 17, 1970 [JA] |
|
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45/112857 |
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Current U.S.
Class: |
181/155 |
Current CPC
Class: |
H04R
1/345 (20130101) |
Current International
Class: |
H04R
1/34 (20060101); H04R 1/32 (20060101); G10k
013/00 (); H04r 001/28 () |
Field of
Search: |
;181/31A,31B,31R,30 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Tomsky; Stephen J.
Claims
What is claimed is:
1. In a speaker apparatus including a cabinet and at least one
speaker unit, the improvement comprising: means secured to said
cabinet for irregularly and diffusively reflecting sound emitted
from said speaker to generate a number of indirect sound waves
having different wave surfaces, said means for reflecting sound
comprising a first substantially semi-cylindrical reflector board
having a plurality of planar reflecting surfaces on the interior
surface thereof, each planar reflecting surface forming an angle
with an adjacent planar reflecting surface of less than 180.degree.
to form alternating projections and recesses around the interior of
said semi-cylindrical reflector board, and a second reflector board
positioned adjacent the end of said semi-cylindrical reflector
board opposite said speaker, said second reflector board having
curved reflecting surface portions, said first and second reflector
boards being disposed in front of said speaker unit to irregularly
and diffusively reflect sound emitted from said speaker unit,
whereby an improved sound field is created in said speaker
apparatus.
2. The speaker apparatus as specified in claim 1, further
comprising a third sound reflecting board having a curved
reflecting surface and being mounted above said speaker in a
spaced-apart relationship with said first and second reflector
boards, wherein the sound waves reflected from said third sound
reflecting board are directed toward said first and second sound
reflector boards.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a speaker apparatus and, more
particularly, to an irregular reflection and diffusion type speaker
apparatus suitable for effective reproduction of a lifelike sound
field.
2. Description of the Prior Art
The so-called lifelike sound field will be reproduced by a spatial
combination of a single direct sound wave emitted from a sound
source and multiple indirect sound waves derived therefrom.
Listeners get a stereophonic effect by sensing mutually related
direct and indirect sound waves through their left and right ears.
Thus, in order to reproduce the lifelike sound field with a high
degree of fidelity, it is necessary to provide an infinite number
of sound transmission channels; this can scarcely be realized.
Hitherto, generally, the reproduction of sound in the form of a
sound field is performed through utilization of sound reflection in
a sound reproducing room; but the resultant reproduced sound field
is short in terms of the indirect sound waves in comparison with a
"live" sound field. Further, though a non-directional speaker is
used to make effective use of sound reflection in the reproducing
room, the overall sound effect is low in case the room has a
decreased sound reflection efficiency. Moreover, there is the
drawback that the afore-mentioned provision results only in a sound
effect similar to that resulting from the use of a directional
speaker because the direct sound wave going towards a listener is
stronger than the indirect sound waves.
In the field of stereophonic reproduction, live sounds emitted from
sound sources are picked up at two left and right locations in
front of the sound sources and recorded in a recording medium. The
recorded sounds are reproduced through left and right speakers
positioned in the sound reproducing room so that the reproduced
sound waves are spatially mixed to give listeners "a sense of
presence." Thus, the afore-mentioned conventional systems are
liable to suffer the influence of the acoustic efficiency of the
reproducing room because the sound waves are spatially combined in
the room.
Accordingly, it is an object of the instant invention to provide a
speaker apparatus suitable for reproduction of a lifelike sound
field.
It is a more specific object of the instant invention to provide an
irregular reflection and diffusion type speaker apparatus which
emits a combination of direct sound waves and reflective indirect
sound waves to produce a lifelike sound field.
SUMMARY OF THE INVENTION
According to the instant invention, there is provided an irregular
reflection and diffusion type speaker apparatus constructed so that
sound signals emitted from one or more speaker units are reflected
by at least one sound reflecting board adapted to reflect sounds
irregularly and diffusively thereby resulting in an effect similar
to the effect obtainable when a number of speaker units are
arranged in the room which emit a number of time-different or
phase-different sound signals or their combination with the result
of generation of a sound field which gives listeners the sense of
presence in the "live" sound field.
Further, the instant invention provides a single speaker apparatus
for stereophonic reproduction which is constructed so that sound
waves emitted from left and right speaker units in a single cabinet
are mixed spatially through irregular reflection to generate the
lifelike sound field which will spread in the reproducing room. The
speaker apparatus is less susceptible of influence of the sound
reflection efficiency of the reproducing room with respect to its
generating sound field.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an embodiment of an irregular
reflection and diffusion type speaker apparatus according to the
invention.
FIG. 2 illustrates the state of reflection of sound waves in a
horizontal plane relating to the embodiment shown in FIG. 1.
FIG. 3 illustrates the state of reflection of sound waves in a
vertical plane relating to the embodiment shown in FIG. 1.
FIGS. 4 and 5 are elevational side views of other embodiments of
the speaker apparatus according to the invention.
FIG. 6 is a perspective view of a still another embodiment of the
speaker apparatus according to the invention adapted for
reproduction of stereo-sound.
FIG. 7 is a perspective view of the embodiment shown in FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIGS. 1 through 3, a cylindrical cabinet 1 with a
bottom board, contains a speaker unit 2 secured thereto facing
upward. The cabinet has sound reflecting boards 3 and 4 mounted on
its upper side and above the speaker unit 2 to reflect sound waves
irregularly and diffusively.
The reflecting board 3 is, for example, of the substantially
semi-cylindrical type in which the interior sound wave reflecting
surface is formed of a plurality of planar surfaces, with each
planar surface forming an angle with an adjacent surface of less
than 180.degree., and generally conforming to the semi-cylindrical
configuration runs in a zigzag fashion, and is secured to the upper
peripheral portion of the cabinet 1. Whereas, the reflecting board
4 has, for example, curved surface portions facing downward and is
secured to the upper end portion of the reflecting board 3
obliquely with respect to the vertical line. Thus, the sound wave
signals in space emitted from the speaker unit 2 travel as shown in
FIG. 2 in a horizontal plane and as shown in FIG. 3 in a vertical
plane.
In FIG. 3, reference characters l.sub.1 through l.sub.n designate
the courses of propagation of various sound wave signals emitted
from the speaker unit 2 in various directions. The sound waves
emitted from the speaker unit 2 are reflected irregularly by the
reflecting boards 3 and 4 so as to have random propagation
directions to thereby transform into "multi-order" signals having
different wave surfaces.
Further, since the resultant reflected signals take different
propagation courses l.sub.1 .about.l.sub.n, they interfere with one
another with differences in time and/or phase therebetween to
generate interference fringes due to existence of a number of
time-different sound signals or phase-different signals or the
combination thereof. The produced interference fringes spread in
the sound reproducing room.
Therefore, it will be apprecaited that the reflection effect of
sound reproduced in the room by the apparatus of the instant
invention is remarkably high in comparision with the result of use
of a conventional single-directional speaker, and the reproduced
sound field in the listening room has the "sense of presence"
similar to the live sound field.
Though there has been described one preferred embodiment of the
instant invention, it should not be limited only to the foregoing
construction. The sound reflecting boards can be embodied in any
forms which can provide irregular reflection of sound, and the
speaker unit can be disposed in the cabinet with an angle of
inclination so as to enhance the effect of sound reflection.
In FIG. 4, showing another embodiment of the instant invention, the
speaker unit 2 is preferably disposed with an inclination to emit
direct sound wave signals, and an additional reflecting board 5 is
positioned in front of the reflecting board 3 above the speaker
unit 2 to increase the effect of sound reflection of the
apparatus.
In FIG. 5, showing still another embodiment, a body 6 in the form
of a plurality of long, thin, irregularly shaped projections or
extensions, is disposed above the speaker unit 2 as a sound
reflecting means to reflect sound irregularly and diffusively.
In FIG. 6 showing one embodiment of the speaker apparatus adapted
to reproduce stereophonic sound, a cabinet 3 contains a left
speaker 1 and a right speaker 2 facing upward. The left and right
speakers are supplied, respectively, with a left and a right
channel signals which were previously recorded on a recording
medium after pick-up at two spaced left and right locations in
front of the live sound field.
The cabinet 3 has a board 4 of the dome type disposed on its upper
side to reflect sound irregularly. The front of the irregular
reflection board 4 is open to define a sound wave emission
port.
According to the sturcture of FIG. 6, the sound waves emitted from
the left and right speakers 1 and 2 reach the dome-shaped irregular
reflection board 4 and are thereby reflected irregularly, then they
propagate randomly to become a number of time-different or
phase-different signals or their combination having mutually
different wave surfaces. The resultant sound signals are mixed
spatially to generate a stereophonic sound field which will then
spread into the sound reproducing room through the sound emission
port.
It should be noted that the irregular reflection board 4 is not
necessarily limited to the dome type, but may have shapes, such as
the form of a ceiling of a conventional concert hall, which
reflects irregularly the sound waves emitted by the left and right
speakers to create a stereophonic sound field wherein the generated
sound field will spread into the reproducing room. The speakers 1
and 2 may be secured to the cabinet with an inclination, different
from the state shown in FIG. 6.
In summary, the instant invention provides a speaker apparatus
which includes sound reflecting means to reflect irregularly and
diffusively sound emitted by a speaker unit in a speaker cabinet to
generate a sound field within the apparatus having a sound emission
port through which the generated sound field spreads into a
reproducing room, so that instant apparatus is less susceptive of
influence of sound efficiency of the room.
* * * * *