US2220177A - Loud-speaker - Google Patents

Description

Nov. 5, 1940. A. J. SANIAL 7 LOUD- SPEAKER Filed March 31, 1938 Zhwentor (Ittorneg Patented Nov. 5, 1940 UNITED STATES LOUD-SPEAKER.

Arthur J. Sanial, Flushing, N. -Y., assignor to Radio Oorporation'of America, a corporation of Dela.-

ware

Application March 31,

4 Claims.

This invention relates to loud-speakers and, more particularly, to a horn structure therefor.

In certain installations of announce systems, it has been found desirable to prevent sounds 5 within predetermined frequency ranges from reaching the diaphragm of the driving unit from the atmosphere. For example, in such installations on board battleships, the low frequency sounds produced by cannon fire have been known to travel back through the horn and to injure the diaphragm. It is the primary object of my present invention to provide an improved horn structure for loud-speakers wherein this danger is obviated.

More particularly, it is an object of my present invention to provide an improved horn structure for loud-speakers wherein sounds entering the horn from the atmosphere will be prevented from reaching the diaphragm.

Another object of my present inventiton is to provide an improved horn structure as aforesaid which is simple in construction and highly eflicient in use.

In accordance with my present invention, I r

5 make the horn of two or more sections and fasten them together with one or more spacers of a given length. The spacers are so arranged as to provide an acoustic by-pass in the horn to prevent the low frequency sound that enters the mouth of the born from reaching the diaphragm.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with additional objects and advantages thereof, will best be understood from the following description of several embodiments thereof, when read in connection with the accompanying drawing, in which Figure 1 is a central sectional view of one form of horn embodying my invention,

Figure 2 is a front elevation thereof, and Figure 3 is an elevation of a different form of spacing device from that shown in Figs. 1 and 2.

Referring more in detail to the drawing, wherein similar reference characters designate corresponding parts throughout, I have shown, in Figures 1 and 2, a loud-speaker comprising a suitable driving unit i which may include a conventional diaphragm (not shown) and to which is coupled a horn formed of two axially-aligned sections 3 and 5. The smaller section 3 is disposed immediately adjacent the driver I, and the larger section 5 is spaced therefrom a predetermined distance in an axial direction, the adjacent 1938, Serial No: 199.323

ends of the horn sections 3 and 5 being provided with radially outwardly extending, annular flanges l and 3, respectively. A plurality of spacers ll of predetermined length are disposed circumferentially about the flanges l and 3 in 5 spaced relation to each other and connect the two horn sections 3 and 5, the spaces l3 between the members H serving as acoustic passages for lay-passing sound below substantially a predetermined frequency.

It will be seen that the spacers H connect the horn sections 3 and 5 into a unitary structure, and the internal contour of the united horn sections in a. longitudinal direction is substantially smooth, that is, without any abrupt changes or 15 interruptions, as clearly shown in Figure 1. The cut-off frequency of the horn assembly may, for example, be made at about 200 or 250 cycles, and this will determine the length of the spacing members H and the distance which they are 20 spaced from each other circumferentially of the horn.

In place of a plurality of spacing'members H, the horn sections 3 and 5 may be connected by a ring-like or annular member 2|, as shown in Fig. 25 3. The member 2| is provided with a plurality of radially extending passages 23 spaced circumferentially about the ring member 2| and corresponding to the acoustic passages l3.

Although I have shown and described two 30 modifications of my invention, it will be apparent to those skilled in the art that many other modifications are possible. I, therefore, desire that my invention shall not be limited except insofar as is made necessary by the prior art and by the 35 spirit of the appended claims.

I claim as my invention:

1. A loud-speaker horn comprising a plurality of horn sections, and spacing means spaced circumferentially about said horn sections connecting said horn sections into a unitary structure, said spacing means providing a plurality of radially extending, circumferentially spaced passages constituting an acoustic by-pass for sounds below substantially a predetermined frequency. 45

2. A loud-speaker horn comprising a pair of horn sections arranged in axial alignment and in spaced relation to each other in an axial direction, and spacing means connecting said sections to each other in said spaced relation, said means 50 having a plurality of circumferentially spaced acoustic passages for by-passing sound below substantially a predetermined frequency.

3. A loud-speaker horn comprising a pair of horn sections arranged in axial alignment and in u spaced relation to each other in an axial direction, the'adjacent ends of said horns having outwardly extending flanges thereon, and spacing means between said flanges connecting said horns into a unitary structure and maintaining said horn sections in spaced relation, said means providing a plurality of circumferentialiy spaced acoustic pasasges for by-passing sounds below substantially a predetermined frequency.

4. The invention set forth in claim 3 characterized in that said connecting means, comprises an annular member having a plurality. of circumferentially spaced, radially extending passages therein.

ARTHUR J. SANIAL.

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