US1840992A - Sound reproducing device - Google Patents

Description

T. WElTLlNG `lan. 12,' 1932.

SOUND REPRODUG I NG DEVI GE Filed Nov Patented Jan. 12, 1932 PATENT OFFICE;

TEBIJON' WEITLING, 0F NEW YORK, Y.

SOUND BEPRODUGING DEVICE 'Appudatmn mea november 27, 1929. seriai 110,410,036.

This invention relates to a sound reproducing device adapted ,to be used in connection with radios, phonographs, talking motion pictures, piano and organ construction or in any other similarl art wherein a sound reproducing or transmitting meansis used and in which a structure of the character hereinafter described is capable of use.

The invention resides in the structure of ahorn, tone chamber, ba'lle board or similar means used as part of a sound reproducing device. It is well known that when a horn or cone is used as part of a loud speaker,

such a horn or cone usually consists of a conical imperforate member and possesses distinct directional characteristics. f That is to say, a horn or cone when used as Valoud speaker acts to ldistribute sound merely in the direction in which the mouth of the horn faces. Incidentally, many horns or other y sound chambersused in loud speakers possess undesirable resonance which acts greatly to y impair the tone quality of the source of sound,

v whether it be radio, phonograph or the like. The object, therefore, of my invention is to provide a horn, tone chamber, baffle board Vor other element in which the undesirable directional characteristics of the ordinary horn, cone or tone chamber will be avoided;

,. which will act to distribute sound in lall directions within the room in which the device is located, and'nally, which will by reason of its construction avoid the resonant characteristics found in many reproducing devices which greatly impair the true reproducing ability of such devices.

In the followingl description, I showl an illustrative embodiment ofimy invention as applied to a horn or similar sound reproduc- 40 .ing device. I do not attempt to illustrate in the drawings the various uses to which the broad idea may be put,'since to do so would result in a needless multiplicity of illustrations. It will be understood however, that when refer to a"horn inwhich I utilize the principle of my invention I may well mean 4 the whole or part of a tone chamber or casing, aportion of a cone-shaped orfdisk loud speaker,y a part of a phonograph, piano or organ or other musical instrument, or a baffle board construction or casing as used in connection with certain types of speakers of the type widely in use at the present time.

Reference is to be had tothe accompanying drawings, forming aA part hereof 1n which Y Figure 1 is a longitudinal `sectional view of an illustrative form of horn made in accordance with my invention;

Figure 2 is a transverse sectional view of the same near theopening or mouth of the horn on the line 2-2 of Figure l, looking in the direction of the arrows;

Figures 3 and 4 are longitudinal sectional views of several of the many modifications of my improved structure;

Figure 5 lis a sectional view in enlarged form illustrating the manner in which a form of horn may be made;

Figure 6 is a sectional view on the line 6--6 of Figure 4 looking in the direction of the arrows, and

Figure 7 is a sectional view showing a modified way of making a cone, horn or any portion of a sound chamber.

` Throughout the various views of the drawings, similar reference characters designate similar parts.

In the illustrative embodiment of my invention disclosed in Figures 1 and 2 of the drawings, ll indicates the'body of a sound reproducing device, which I have 'shown in simple horn form. As heretofore pointed out however, the structure lmay well be a casing for a ,speaker or a wall or wall section orl series of such sections for any other type of sound reproducing device: The simple conical type of horn shown is provided with the vusual bell or mouth 2 and contracted opposite end 3 which receives the reproducing unit 4. In carrying out my invention, the horn is made of a body 5 which may be made of any suitable material of sufiicient stiffness to maintain the horn in its proper shape. I contemplate the use of thin perforate metal, papieranche, wire mesh, wood, wicker, bamboo, o-r any other material suitable for the purpose. The stiff material 5 forming the body of the horn is preferably provided throughout its entire surface with a series of perforations G. Any foraminous material such as a skeleton frame work of strip material with spaces between will suilice. These perforations can be very closely spaced; they may vary in shape and-size; they `may be situated in various areas of the horn and they may be in the form of slits, slots or various shaped openings. These perforations may be placed throughout the area of the horn or they may be localized to suit different requirements of sound distribution. It is also entirely feasible to use one or more large openings in place of a series of small openings, if desired.

To dampen out undesirable resonance in the horn, I find it desirable to line both inner and outer faces of the horn with a suitable sound dampening material such as indicated at 7 and 8. This material may be in the form of loosely compacted felt, bui-lap, carpet, plush, felt, sponge rubber or 'some other material of similar characteristics placed on in single or multiple thickness. It is not perforated but is preferably of open characteristics to the extent of permitting penetrability of the sound.

Through the structure just described, it Will be seen that by the provision of openings in the side Walls of a sound reproducing device, the directional characteristics of snch device are dissipated. There isa tendency for the sound to extend laterally through the openings and dampening covering, the amount of such lateral disposition of the sound being dependent upon the size and shape of such openings and upon the location of the same, together with the'thickness and density of the fabric covering.

It is true that by the utilization of such a structure that I have just described, the volume is slightly decreased. This is however, relatively unimportant since most radio sets, microphones, phonographs and other sound reproducing devices are to-day operated with more power than actually needed. This loss of power is amply compensated for in my device by distinct gain in clarity and naturalness of tone, with reserve volume to hold vunder control.

In Figure 3 a horn is shown in which perforations 2O are.. provided throughout the .area of the inner stiifening layer, and only a portion of the horn is covered by the dampening layer 22.

In Figure 4, I have illustrated an embodi ment of my invention wherein a horn-shaped member 9 is disclosed, the same being built up of a substantially rigid body 5 and resonance dampening outer and inner layers 7 and 8, similar to those described with respcct to Figure l. The shape of the horn employed however, differs from that disclosed in Figure l since I provide it with transverse partitions l0 and Il, the inner layer of these partitions being provided with a plurality of perforations 12 and 13 and these partitions being' covered by imperforate dampening fabric on one or both of their faces. Additionally, I provide the horn 9 with a surrounding concentric enclosure member I4, the supporting inner layer of which may be Vperforated as at l5, and also covered with resonance-dampening fabric on one or both of its faces.

The structures illustrated in Figures 3 and Li are several of many forms that may be employed to cause the sound waves reproduced topass through a devious course before actual exit into the room. A dampening tendency and a dissipation of resonance is thereby secured.

I have herein described several embodiments of my invention which is capable of many modifications. The perforated principle, combined with the utilization of resonance dainpening means may be applied to any type of tone chamber. If desired, a horn may beprovided with a series of perforated and dampened baille plates, a suggestion of which is contained in Figure Li. These and many other modifications may be made in my invention, without departing from its spirit.

I-Iaving described my invention, what I claim is:

l. In a sound-reproducing device, a soundreproducing unit and a sound-amplifying wall structure directly associated therewith, said structure having a wall portion provided with openings, and a sound-dampening element consisting of a soft, penetrable substance extending over said Wall portion and covering the openings therein.

2. A sound-reproducer having a sound-reproducing unit, an amplifying wall structure connected to said unit and directly associated therewith for ,so-und reproduction, said structure having a wall portion provided with openings in it, one face of said wall portion and the openings therein being covered by a soft, penetrable sound-da1npening element.

3. A soundaeproducer having a sound `chamber provided with a wall in the form 'of a perforated element, the face of said elea sheet of soft, permeable sound-dampening fabric covering the wall and the perforations therein.

5. A sound-reproducer having a sound chamber provided with a Vperforated wall structure, a part of which 1s covered by a soft, resonance-dampening textile fabric.

6. A sound reproducer having a sound chamber provided with a. perforated wall layer and a. soft, penetrable dampening material disposed on opposite faces of said wall.

Signed at the oit of New York, county of New York, and tate of New York, this 26th day of November, 1929.

TERIJON WEITLING.

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