US1820956A - Loud speaker - Google Patents

Description

Sept. 1, 1931.

G; VON ARCO LOUD SPEAKER Filed Nov. 27 1925 INVENTOR G KG VON ARCO ATTORNEY Patented Sept. 1, 1931 UNITED STATES PATENT OFFICE GEORG VON ABCO, O]? BERLIN, GERMANY, ASSIGNOR T GESELLSCHAFT FR DRAHT- LOSE TELEGRAP-HIE M. B. H., OF BERLIN, GERMANY, A CORPORA'IION OF GERM'ANY LOUD SIEEAKER Application filed November 27, 1925, Serial N0. 71,615, and in Germany December 24, 1924.

This invention relates to means for comverting electrical impulses into sound or speecl1 waves, which said devices are commonly known in the radio art as loud speakers.

Common objections to the usual type of 1011d speaker are that they are unsightly in appearance, directional in their results and lacking in true quality reproduction. Thisinvention has for its ob ect to eliminate these undesirabilities and its purpose is to make it possible to construct a loud speaker of pleas1ng design and capable 0f giving non-directional and true reproduction.

Referring to the drawings, Fig. 1 represents a side view of' the mechanical stracture;

Fig. 2represents a view taken along the line 2-2 of Fig. l.

Fig. 3 shows a slighfly diflerent form of myinvention. F Fig. 4 is an end view of the device 0f 1g. 3. If two telephones are mounted parallel 575 with reference to one an other at a small distance apart, say to 1 cm. with their openings turned towards each other, they exhibit a considerable amplification of their acoustic actions. It is upon this discovery' 39 and principle upon which the idea Underof sound, there is obtained a reinforced action. T0 avoid disturbing natural Vibrations of tl1e suirfaces bounding the acoustic Sfl}(3e a good and suitable plan' is to divide t e acoustic space by means of radial partitions, int0 difl'ercnt compartments (F ig.

2), with tl1e result that tl1e whole arrange- 'ment forms a s0rt 0f individual composite -construction is illustrated in Fig. 8 oflhe accompanying drawings which illustrates a section through the tw0 surfaces F1 and F2, with the telephones T1 and T2 being arranged in the center 0f each surface. Also in a device of this kincl, the bridging 01 connection of the individual surfaces by means of radial partitions 01 ribs unitingthe two surfaces, would be a suitable sche1ne in order to thereby suppress the natural vibration of the large surfaces. But the stif= fening of the surfaces may be accomplished also by the arrangement of radial ribs out-- siole the acoustic space for each surface individually. Such a series of ribs R is shown in Figs. 3 and 4 extending from points adjacent the telephones to the edges of the plates, the kribs being arranged on the coucave surface of the plates so as not t0 interfere with the acoustic properties of t-he device.

' From the above description of the mechanical essentials of an embodiment of my invention it can readily be seen that a loud speaker capable of reproducingtrue and non-directional sound waves may.be comstructed and housed in a suitable cabinet of pleasing design.

Having fully described my invention, I claim:.

1. In a loud speaker, a plurality of vibrating diaphragms, and a plurality of curved disks, said diaphragms being centrally disgosed therein and said disks and diaphragms eing positioned to oppose eacl1 othcr und form a trumpet-like acoustic chamber therebetween. 1

2. In an acoustic device, two adjacem;

members positioned to form an acoustic chamber there-between, means for producing sound vibrations within such chamber and means for preventing' said members from vibrating in sections.

3. In an acoustic device, two adjacent disks, the inner surfaces thereof beingopposed to form an acoustic chamber and means cooperating. with the outer surfaces 130 prevent sectional vibrations of said disks.

4. A unit for an acoustic device, said unit haVing a convex face for amplifying sound and an oppositely disposed face and rneans attached to the latter face 130 stiflen said said unit.

5. In combination a plurality of umsonnected surfaces and a sound producing means in each surface, said surfaces being arranged to form an acoustic chamber by themselves and. said sound producing means acting simultaneously to produce comp1essions 01' rar efactions, in said acousfiic charnber.

In combination a plurality of vibrating members and means surrounding each of said vibrating members and positioned to form an acoustic chamber having an opening extending thr ough an angle .of 360 whereby sound waves are propagated in all directions, said vibrating membe1s being operated to simultaneously produce compressions or rarefaetiohs in said acoustic chamber. y

7 In combination a plurality 0f vibrating members arranged to direct sound waves in diflerent directions and means positioned t0 surround each 01 said vibrating members to form an acoustic chamber, said chamber having an opening for directing sound waves in eyery direction in one plane, said vibrating members being operated to simultaneously produce compressions 01 rarefactions in said acoustic chamber.

GEORG VON ARCO.

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