GB2045578A - Speaker device - Google Patents
Speaker device Download PDFInfo
- Publication number
- GB2045578A GB2045578A GB7909529A GB7909529A GB2045578A GB 2045578 A GB2045578 A GB 2045578A GB 7909529 A GB7909529 A GB 7909529A GB 7909529 A GB7909529 A GB 7909529A GB 2045578 A GB2045578 A GB 2045578A
- Authority
- GB
- United Kingdom
- Prior art keywords
- walls
- air chamber
- speaker device
- elastic
- porous material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000011148 porous material Substances 0.000 claims abstract description 18
- 230000035699 permeability Effects 0.000 claims 2
- 239000000463 material Substances 0.000 abstract description 11
- 239000004033 plastic Substances 0.000 abstract description 2
- 229920003023 plastic Polymers 0.000 abstract description 2
- 239000004816 latex Substances 0.000 description 7
- 229920000126 latex Polymers 0.000 description 7
- 230000010355 oscillation Effects 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
- H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only
- H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
- H04R1/2807—Enclosures comprising vibrating or resonating arrangements
- H04R1/2815—Enclosures comprising vibrating or resonating arrangements of the bass reflex type
- H04R1/2819—Enclosures comprising vibrating or resonating arrangements of the bass reflex type for loudspeaker transducers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
- H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only
- H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
- H04R1/2869—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself
- H04R1/2876—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself by means of damping material, e.g. as cladding
- H04R1/288—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself by means of damping material, e.g. as cladding for loudspeaker transducers
Landscapes
- Health & Medical Sciences (AREA)
- Otolaryngology (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Details Of Audible-Bandwidth Transducers (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
- Building Environments (AREA)
Abstract
A loud-speaker unit composes a box 1 housing a loud-speaker 2 and an air chamber 3 bounded by walls 4. The walls 4 of the air chamber 3 are made of elastic-porous material, e.g. foamed rubber-like plastics material, to minimise unwanted resonances of the unit. The walls 4 may be surrounded by a rigid housing 5. The loud-speaker unit can be used in household audio systems such as radio-sets and record players, as well as in special purpose acoustic systems, such as cinema and studio apparatus. <IMAGE>
Description
SPECIFICATION
Speaker device
The present invention relates to the field of electro-acoustics and more particularly to speaker devices of phase inverting type.
It is of the most advantage to use the present invention in the house-hold audio systems such as radio-sets and electric phonographs, as well as in specially purposed acoustic systems, such as cinema and monitoring-studio apparatus.
According to the invention there is proposed a speaker device comprising a box with a speaker and an air chamber mounted therein, wherein, according to the invention, the air chamber walls are made of elasticporous material.
The air chamber walls made from elasticporous material make the effective resistance of the walls to the air stream higher than the acoustic reactance of the air mass in the chamber on the frequencies close to the basic resonance frequency of the speaker device.
Owing to that, the air chamber wall affect little the resonant properties of the speaker device, but significantly absorb standing waves, thus eliminating unwanted by-sounds.
It is expedient the specific volume elasticity of the elastic-porous material be from 4 10-6 to 5010-6 m2/N, and the specific volume resistance to the air stream passing through the chamber wall be from 0.1 10-3 to 5 10-3 mech.ohm.m.
The specific volume elasticity of the elasticporous material being less than 4.106 m2/N and the specific volume resistance to the air stream passing through the chamber walls being higher than 5 10-3 mech.ohm.m., there appear standing waves in the air chamber, this leading to an unwanted amplification of by-sounds.
If the specific volume elasticity of the elastic-porous material is higher than 50 1 0-6 m2/N and the specific volume resistance to the air stream through the chamber wall is less tha 0.1 10-3 mech.ohm.m, then the air stream would pass through the chamber walls and detune the speaker device. Moreover, such an eiastic-porous material cannot be mounted within the box without any additional rigid frame.
It is advisable to fix a rigid housing on the outer sides of the air chamber walls.
The rigid housing being fixed on the outer sides of the air chamber walls enables to use the elastic-porous material with higher specific volume elasticity and less specific volume resistance to the air stream passing through the air chamber walls, which, in turn, ensure more dependable elimination of standing waves in the air chamber with resultant weakening of the unwanted by-sounds.
It is desirable to use the elastic-porous
material having the specific volume elasticity
ranging from 4.10-6 to 1 50.10-6 m2/N and
the specific volume resistance to the air
stream passing through the chamber walls,
from 0.05 10-3 to 5.10-3 mech.ohm.m.
If the specific volume elasticity of the elas
tic-porous material is higher than 1 50'1 0-6 m2/N and the specific volume resistance to
the air stream passing through the chamber
walls is less than 0.0510-3 mech.ohm.m.,
then the structural rupture of the elastic-po
rous material would occur.
The present invention will become herei
nafter more apparent from the following de
tailed description of the embodiments taken in
conjunction with the accompanying drawings,
in which:
Figure 1 represents a speaker device, ac
cording to the invention;
Figure 2 represents an other embodiment of
the speaker device, according to the inven
tion;
Figure 3 represents a graph showing by
sound level in the air chamber versus fre
quency response, according to the invention;
Figure 4 represents a graph showing sound
pressure-frequency response, according to the
invention.
The speaker device comprises a box 1 (Fig.
1) wherein a speaker 2 and an air chamber 3
formed by walls 4 are mounted. The walls 4
of the air chamber 3 are made of elastic
porous material with the specific volume elas
ticity ranging from 4.10-6 to 50.10-6 m2/N
and the specific volume resistance to the air
stream from 0.1 10-3 to 5.10-3 mech.ohm.m.
For instance, the walls 4 may be made of
latex or porolone (foamed rubber-like plastic)
etc.
Fig. 2 shows a speaker device with a rigid
housing 5 fixed to the outer sides of the air
chamber walls 4.
In this case the walls 4 can be made of
elastic-porous material with the specific vol
ume elasticity ranging from 4.10-6 to 150 10-6 m2/N and with the specific resis
tance to the air stream from 0.0510-3 to 5 10-3 mech.ohm.m.
For example, to line the walls 4 one may
utilize felt, sheet wadding, etc.
The speaker system operates as follows.
When high power signals are radiated by the
speaker 2 on frequencies close to the basic
resonance frequency of the speaker device, air
mass oscillations of large amplitude are gener
ated in the air chamber 3 wherein standing
waves are excited and are successively ab
sorbed by the walls 4 of the chamber 3, thus
banishing appearance of unwanted by-sounds.
On the graph shown in Fig. 3 a curve "A"
represents the by-sounds level in the chamber
3 versus frequency response in the band of
1/3 octave, in case the walls 4 of the cham
ber 3 are made of hard material; a curve "B" represents the by-sound level in the chamber 3 versus frequency response in the band of 1/3 octave, in case the walls 4 of the chamber 3 are made of elastic-porous material /latex, for example/ having the specific volume elasticity from 4.10-6 to 50.10-6 m2/N and the specific volume resistance to the air stream from 0.1 10-3 to 5-10-3 mech.ohm.m; a curve "C" represents the by-sound level in the chamber 3 versus frequency response in the band of 1/3 octave, in case the rigid housing 5 is fixed on the outer sides of the walls 4 of the chamber 3 and the walls 4 are made of elastic-porous material/sheet wadding, for example/ with the specific volume elasticity from 4.10-6 to 150.10-6 m2/N and the specific volume resistance from 0.05 10-3 to 5 10-3 mech.ohm.m; the frequency "f", given in Hz, is plotted on X-axis while the bysound level, given in dB, is plotted on Y-axis.
While examining the curves "B" and "A" /Fig. 3/, it can be seen that the speaker device with the walls 4 made of latex, when reproducing low frequencies approaching the standing waves, in the range from 1000 to 300 Hz provides for by-sounds attenuation approximately by 8-9 dN in comparison with the speaker device whose walls are made of hard material.
While examining the curves "C" and "B", it is seen that the speaker device with the rigid housing 5 fixed on the outer sides of the walls 4 the walls 4 themselves being made of sheet wadding, when reproducing low frequencies approaching the standing waves, in the range from 1000 to 12,0000 Hz provides for by-sounds attenuation, approximately by 2-8 dB as compared with the speaker device having the walls 4 made of latex.
On the graph shown in Fig. 4 a curve "D" represents the pressure-frequency response of the speaker device whose walls 4 of the air chamber 3 are made of hard material; a curve "E" represents the pressure-frequency response of the speaker device whose walls 4 of the air chamber 3 are made of elasticporous material /latex, for example/ having the specific volume elsaticity ranging from 4.10-6 to 50.10-6 m2/N and the specific volume resistance to the air stream from 0.1 10-3 to 510-3 mech.ohm.m.; a curve "F" represents the pressure-frequency response of the speaker device having the rigid housing 5 fixed on the outer sides of the walls 4 of the air chamber 3 the walls 4 themselves being made of elastic-porous material /sheet wadding, for example/ having the specific volume elasticity from 4 10-6 to 150 10-6 m2/N and the specific volume resistance to the air stream from 0.05 10-3 to 5.10-3 mech.ohm.m.; the frequency "f", given in Hz, is plotted on X-axis, while the sound pressure, given in dB, is plotted on Y-axis.
While examining the curves "E" and "D" /Fig. 4/, it can be seen that the speaker device whose walls 4 are made of latex, has a non-uniform pressure-frequency response in the range from 1000 to 3000 Hz, which is approximately by 5 dB less than that of the speaker device whose walls 4 are made of hard material.
While examining the curves "F" and "D", it can be seen that the speaker device with the rigid housing 5 fixed on the outer sides of the walls 4, the walls 4 themselves being made of a sheet wadding, has a non-uniform pressure-frequency response in the range from 1000 to 12,000 Hz, which is approximately by 0.5 to 1 dB less than that of the speaker device having walls 4 made of latex.
Thus, fabrication of the walls 4 of elasticporous material gives a possibility, on great oscillation rates of air in the air chamber 3, to eliminate the by-sounds excited by standing waves without decrease in sound pressure on the frequencies close to the natural resonance frequencies of the speaker device, as well as to level the frequency response in the range of standing waves absorption in the air chamber 3 of the speaker device.
Although, the present invention has been hereinbefore described with respect to the preferred embodiment, it should be also apparent for those skilled in the art that various modifications and substitutions of the proposed speaker device might be made without departing from the spirit and scope of the invention.
Claims (6)
1. A speaker device comprising a box wherein a speaker and an air chamber are mounted, the walls of the air chamber being made of an elastic-porous material.
2. A speaker device as set forth in Claim 1 wherein the elastic-porous material has a specific volume elasticity from 4'1 0-6 to 50.10-6 m2/N and a specific volume resistance to the air stream passing through the walls of the air chamber from 0.1 10-3 to 5 10-3 mech.ohm.m.
3. A speaker device as set forth in claim 1 wherein a rigid housing is fixed on the outer sides of the walls of the air chamber.
4. A speaker device as set forth in claim 3 wherein the elastic-porous material has a specific volume elasticity from 4 10-6 to 150 10-6 m2/N and a specific volume resistance to the air stream passing through the walls of the air, chamber from 0.05 10-3 to 5 10-3 mech.ohm.m.
5. A loudspeaker unit substantially as hereinbefore described with reference to Fig. 1 or
Fig. 2 of the accompanying drawings.
5. A speaker device essentially as hereinbefore described and shown in Figs. 1 and 2 of the accompanying drawings.
CLAIMS (11 Feb 1980)
1. A loudspeaker unit of phase inverting type comprising a box wherein a speaker and an air chamber are mounted, the air chamber leading from the interior to the exterior of the box and internal walls of the air chamber being made of an elastic-porous material.
2. A loudspeaker unit as set forth in claim 1 wherein the elastic-porous material has a volume compressability from 4. 10-6 to 50.10-6 Pa-' and a volume permeability to the air stream passing through the walls of the air chamber from 0.12.10-5 to
6.10-5m2/sec Pa.
3. A loudspeaker unit as set forth in claim 1 wherein a rigid housing surrounds the outer surface of the walls of the air chamber.
4. A loudspeaker unit as set forth in claim 3 wherein the elastic-porous material has a volume compressability from 4,10-6 to 1 50.10-6 Pa-l and a volume permeability to the air stream passing through the walls of the air chamber from 0.12.10-3 to 12.10-5 m2/sec Pa.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SU2648740 | 1978-08-11 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2045578A true GB2045578A (en) | 1980-10-29 |
| GB2045578B GB2045578B (en) | 1983-05-05 |
Family
ID=20778840
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7909529A Expired GB2045578B (en) | 1978-08-11 | 1979-03-19 | Speaker device |
Country Status (5)
| Country | Link |
|---|---|
| DE (1) | DE2911849C3 (en) |
| FI (1) | FI790850A (en) |
| FR (1) | FR2433268A1 (en) |
| GB (1) | GB2045578B (en) |
| GR (1) | GR66647B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AP146A (en) * | 1989-06-20 | 1991-10-02 | Amneus Eng | Acoustic speaker device. |
| GB2318475A (en) * | 1996-10-21 | 1998-04-22 | B & W Loudspeakers | Reflex loudspeaker port has lining with a coarse texture |
| WO1999005887A1 (en) * | 1997-07-26 | 1999-02-04 | Koninklijke Philips Electronics N.V. | Loudspeaker system having a bass-reflex port |
| ITVI20090277A1 (en) * | 2009-11-17 | 2011-05-18 | Sonus Faber S P A | PROJECT FINDINGS FOR RESONANCE ROOMS AGREEMENT IN SPEAKER SYSTEMS |
| GB2523143A (en) * | 2014-02-14 | 2015-08-19 | Gb Acoustics Uk Ltd | Loudspeaker bass reflex system |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3113281A1 (en) * | 1981-04-02 | 1982-10-21 | Standard Elektrik Lorenz Ag, 7000 Stuttgart | Loudspeaker box constructed as a bass reflex enclosure |
| DE68919495T2 (en) * | 1988-03-25 | 1995-07-20 | Yamaha Corp | Acoustic apparatus. |
| US5109422A (en) * | 1988-09-28 | 1992-04-28 | Yamaha Corporation | Acoustic apparatus |
| DE3920060A1 (en) * | 1989-06-20 | 1991-01-03 | Mb Electronic Gmbh | Loudspeaker housing with acoustically damped resonator opening |
| DE9005642U1 (en) * | 1990-05-18 | 1990-08-02 | Salzburg, Herbert, Dr., 5000 Köln | Resonance housing for installing loudspeakers |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB747263A (en) * | 1953-05-21 | 1956-03-28 | Goodmans Ind Ltd | Improvements in or relating to loudspeaker cabinets |
| FR2334259A1 (en) * | 1975-12-01 | 1977-07-01 | Art Acoustique Appliquee | Open labyrinth acoustic cabinet - has sectional sound pipe with fibre glass filter producing linear low frequency response |
| FR2414275A1 (en) * | 1978-01-06 | 1979-08-03 | Chalambeau Max | Acoustic enclosure for loudspeaker - has two chambers linked by internal opening and both communicating with atmosphere via shared pipe |
-
1979
- 1979-03-13 FI FI790850A patent/FI790850A/en not_active Application Discontinuation
- 1979-03-19 GB GB7909529A patent/GB2045578B/en not_active Expired
- 1979-03-26 DE DE19792911849 patent/DE2911849C3/en not_active Expired
- 1979-05-11 GR GR59064A patent/GR66647B/el unknown
- 1979-08-03 FR FR7920021A patent/FR2433268A1/en active Granted
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AP146A (en) * | 1989-06-20 | 1991-10-02 | Amneus Eng | Acoustic speaker device. |
| GB2318475A (en) * | 1996-10-21 | 1998-04-22 | B & W Loudspeakers | Reflex loudspeaker port has lining with a coarse texture |
| US6019188A (en) * | 1996-10-21 | 2000-02-01 | B & W Loudspeakers Limited | Enclosures for loudspeaker drive units |
| GB2318475B (en) * | 1996-10-21 | 2000-08-23 | B & W Loudspeakers | Enclosures for loudspeaker drive units |
| WO1999005887A1 (en) * | 1997-07-26 | 1999-02-04 | Koninklijke Philips Electronics N.V. | Loudspeaker system having a bass-reflex port |
| US5892183A (en) * | 1997-07-26 | 1999-04-06 | U.S. Philips Corporation | Loudspeaker system having a bass-reflex port |
| ITVI20090277A1 (en) * | 2009-11-17 | 2011-05-18 | Sonus Faber S P A | PROJECT FINDINGS FOR RESONANCE ROOMS AGREEMENT IN SPEAKER SYSTEMS |
| GB2523143A (en) * | 2014-02-14 | 2015-08-19 | Gb Acoustics Uk Ltd | Loudspeaker bass reflex system |
| GB2523143B (en) * | 2014-02-14 | 2021-04-28 | Gp Acoustics Uk Ltd | Loudspeaker bass reflex system |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2433268B1 (en) | 1983-05-06 |
| DE2911849A1 (en) | 1980-03-20 |
| GR66647B (en) | 1981-04-07 |
| GB2045578B (en) | 1983-05-05 |
| FR2433268A1 (en) | 1980-03-07 |
| DE2911849C3 (en) | 1981-12-17 |
| FI790850A (en) | 1980-02-12 |
| DE2911849B2 (en) | 1981-03-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |