Acoustics – Sound-modifying means – Space absorbers
Patent
1985-06-27
1986-08-12
Fuller, Benjamin R.
Acoustics
Sound-modifying means
Space absorbers
181 30, 181286, 181288, 181290, 181294, E04B 182
Patent
active
046050930
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a device for absorbing sound waves and intended for use as an internal facing, primarily in so-called echo-free rooms, in which recording and measurement of sound are carried out by means of sensitive measuring instruments.
Devices of said type are suited for use in all rooms where a high degree of reflection freedom is desired, e.g. in measuring rooms made in accordance with international standard, ISO 3745, in sound and picture recording studios, in sound laboratories etc. In all these rooms a sound field is desired which corresponds to free sound wave propagation, the strenght of the sound reflex in the limiting surfaces being very small. According to the ISO-standard a sound absorption ability of 99.9% is required within the current frequency range, but in certain cases a sound absorption ability of 99.0% in a medium high sound frequency range from e.g. 200 Hz is sufficient.
A device of the intended type should be well suited as facing both on walls, in ceilings and on floors.
Previously known constructions for absorption of sound waves in echo-free rooms comprise primarily facings in the form of wedges of blocks and wads or cubes of sound absorbing material suspended in threads in immediate connection with walls, ceilings and floors. The purpose of the used constructions is to achieve impedance adaption of the propagation medium, i.e. air, in the intended room in order to obliterate in this way the limit of the propagation of the sound waves.
The known constructions have many shortcomings. Thus, they require separate, specially designed building elements the manufacture of which is expensive. These building elements are often difficult to assemble, especially in connection with floors and ceilings and therefore involve a time-consuming work. Moreover, it is difficult and in certain cases impossible to clean them. It is also difficult to replace damaged building elements of this type. As the building elements comprise unprotected mineral fiber material there is also a great risk of fibers coming loose, the environment of the room being deteriorated.
It is now the object of the invention to provide a sound absorption device eliminating all the disadvantages in connection with known constructions, particular stress being laid on utilizing simple building elements easy to mount and giving a very high sound absorption. This is achieved in that the absorption device of the invention comprises a substrate support which e.g. consists of mineral wool sheets or plate to which plate-shaped sound absorbents, preferably of mineral wool are inclined relative to each other in such a way that they will have a wave-shaped cross-section. The angle between two sound absorbents placed on the substrate support with their edges close to each other should be easily adjustable and is chosen in such a way that the sound waves deriving from a sound source are always reflected at least twice against the sound absorbents before they leave the device. In order to obtain further improvement of the sound absorption ability at the lower portion of the intended frequency range the substrate support together with two adjacent sound absorbents placed on the substrate support should, moreover, define a cavity with a gap-shaped opening disposed between the sound absorbents and/or between sound absorbent and substrate support, which opening is so adapted that cavity resonance is obtained at a predetermined lower frequency range.
A sound absorption device built in the abovementioned manner can utilize usual rectangular plane mineral wool plates of a standard format as sound absorbents. The width of the plates is chosen in dependence of desired lower limit frequency of the operating range of the sound absorbents.
The invention will now be described more in detail below in the form of a preferred illustrative example with reference to the accompanying drawing.
FIG. 1 is a top plan view of a section of an echo-free room comprising the sound absorption device of the invention.
FIGS. 2A and 2B disclose on an enlarged s
REFERENCES:
patent: 2980198 (1961-04-01), Eckel
patent: 3404498 (1968-10-01), Espinoza
Fuller Benjamin R.
Gullfiber Akustik AB
LandOfFree
Device for absorption of sound waves does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for absorption of sound waves, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for absorption of sound waves will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1931972