US1741508A - Acoustic reproducer horn suitable for use with radio sets - Google Patents

Description

Dec. 3l, 1929. P. E. EDELMAN 1,741,508

ACOUSTIC REPRODUCER HORN SUITABLE FOR USE WITH RADIO SETS Original Filed June 5. 1922 :naman 4 Z 5 i INVENToR Patented Dee." '31,1929

UNITED STATES PATENT OFFICE PHILIP E. EDELMAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO EPHRAIM BANNING, OF CHICAGO, ILLINOIS ACOUSTIC REPRODUCER HORN SUITABLE FOR USE WITH RADIO SETS Original application led June 5, 1922, Serial No. 566,132. Divided and this application filed November 28,

An object ofthe present invention, which is divided from my original application S. No. 566,132 filed June 5, 1922, is to provide a reproducer horn of better tonal qualities substantially free from air column resonance and without distortion effects. I accomplish these objects by a novel construction of the reproducer horn whereby the cross sectional area of the horn progressively increases along its length so that for predetermined equally spaced intervals along such length such cross section is substantially doubled, while at the same time the thickness of the wall of the horn preferably increases in similar proportion, being thin at the small end and increasing in thickness toward the large end as the thickest Wall portion.

,My invention is illustrated in the accompanying drawing in which the figure is a longitudinal section through a horn embodying the invention.

A holder 1 contains the reproducer unit 4. Cord wire 5 connects with unit 4 to actuate it. A support 2 holds unit 4 against a yielding gasket 7 in holder 1. Gasket 7 corresponds in contour to the cap 9 of unit 4. Support 2 is held to holder 1 by screw 3. A channel 6 is provided in holder 1 to accc umodat cord 5.

The reproducer horn 12 has a taper neck portion 10 wedged to fit into holder 1 at opening 8. Horn 12 has an orifice E. The wall 11 of neck 10 increases progressively along the length of neck 10, beinig the thinnest near orifice E. The cross section area of the horn portion 10 increases continuously starting at orifice E so that such area is approximately doubled for each such predetermined successive interval along the length thereof.

The goose-neck portion 13 of horn 12 is similarly proportioned continuing from neck portion 10 so that the wall thickness ot gooseneck 13 increases progressively as the distance away from orifice E increases, while the cross section area of said horn also continues to increase at the same rate as in the case of throat neck portion 10 up to the orifice portion D.

A bell portion 14 extends from goose-neck portion 13 and similarly has itswall thick- Serial ness progressively increased along the length thereof while the diameter increases in a ratio per unit length approximately the same as for goose-neck portion 13, the largest cross section being at C, and greatest wall thickness at F.

Vood or wood fibre is suitable for making the horn 12. The air column starting at oriiice E and continuing to rim 16 of bell portion 14 is then confined byprogressively increased Wall sections per unit length corresponding to increased cross sections per unit length from orifice E to rim 16 so that air column resonance and pick-up of secondary vibrations from the horn 12 is substantially avoided. The junction of portion 14 to gooseneck 13 at 17 must be smooth. Radii to secure the aforesaid proportioning can` be located as indicated by M, K, J, L, H, and G. rThe dimension A is greater than the dimension B. By such proportionment clear and true reproduction can be obtained from horn 12 under control of reproducer unit 4 which may be actuated for example by a radio receiving set.

It is permissible to depart somewhat from an exact doubling of cross section at equal intervals along the length'of the horn, especially at the bell portion 14 but the wall thickness should in such case be correspondingly changed to preserve the relative proportions of the air column area at any particular unit cross section to the thickness ot the wall of the horn 12 at such position. The marked iinprovement of such construction will be noticed especially on reproduction of organ music and bass notes but the absence of tinny or high pitched sounds due to actions between the horn 12 and its air column 15 is also pronounced, leaving the vibrations of air column 15 substantially wholly under theinfluence exclusively of the reproducer unit 4 whereby undistorted amplification is attained through said confined air column.

While I have shown and described but a single embodiment of myinvention, it is to be understood that it is capable of many modications. Changes, therefore, in the construction and arrangement may be made which do not depart from the spirit and scope of the invention as disclosed in t-he appended claims.

I claim:

l. An acoustic reproducer horn having input. and output orifices terminating a restricted air column, the cross section area of said air column increasing progressively from said input orifice to said output orifice so that for predetermined successive equal intervals along said distance 'therebetween such cross section. is substantially doubled.

2. An acoustic reproducer horn having a restricted air column and confining wall therefor, an input and an output ori ce for said h orn, the cross section of said air column increasing progressively from said input ori- .fice to said output orifice at a rate which approximately doubles the area thereof for predetermined successive equal intervals between said orifices, and the thickness of said wall progressively increasing proportionately, the

greatest thickness thereof being near, said output orifice.

3. Anv acoustic reproducer having a restricted air column and confining wall therefor with input and output orifices, the cross section of said air column continuously doubling in area for successive equal increments along the length of said air column while the thickness of said wall proportionately in-.

. output orifices,'the area of said air column at said input orifice being theleast and progressively increasing by increments to the greatest area thereof at said output orifice while said wall similarly increases in thick ness by proportionate increments, each successive increase ef air Column area being bounded by a wall portion of similarly successively increased thickness.

6. An acoustic reproducer horn consisting of a confined air column retained by a wall with the input and output orifices, the cross section area of said aircolumn increasing progressively by increments along the length of said air column whereby said area approxi'matclyv doubles for predetermined successive equal intervals along said length, and the thickness of said Wall correspondingly increasing by increments, beingthicker for each successive increment corresponding to said increase of air column area, and an ac-V tuating reproducer unit held in position at said input orifice.

In witness whereof, I have hereunto set my hand this 13th day of Au ust, 1927.

PHLIPE. EDEL AN. [1.. s]

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