US2102736A - Acoustical device - Google Patents

Description

Dec. 21, 1937. H F, OLSON 2,102,736

ACOUSTICAL DEVICE Filed Nov. 21, 1933 I INVENTOR HARRY F. OLSON v VKKM ATTORNEY granted on an application of Julius Weinberger-v tween the end pieces l5 which cover the upper to apart of the ribbon diaphragm. The structo' the rear of the device. This structure, howgo In accordance with the present invention,- the 1, The b t on of magnetic field producing v ph'ragm, is filled with tufts of felt or the like and the conductor and arranged t form a passage- 25 response to sound wave pressure and is of rela- The combination of magnetic flem'producmg. 30

f ther objectis toprovide a ribbon microphone 4o scope will be pointed out in the appended claims.

Patent ed Dec. 193? I v v I I UNITED STATES PATENT oFFicE arry F. Olson, Collingswood, N. J., assignor to Radiov Corporation of America, a corporation ot Delaware v Application November 21, 1933, Serial No. (99,090

6 Claims. (01. nag-13s) This invention relates generally to devices for I and pole pieces l2. To the rear of the diaphragm producing electrical currents which are depend- J0. and within the chamber formed by the magent on and vary as the waves of sound and, more netic structure is located a member I3 arranged particularly, to readily portable microphones or to form awinding passageway or labyrinth. This 5 sound pick-up devices which are responsiveto the passageway-opens at the rear of the diaphragm pressure of a sound wave. r and may be loaded with felt filling ll or tu'fts of A microphone responsive to both the velocity felt for rendering theimpedancepresented to the component and the pressure-of a. sound wavevis diaphragm independent offfrequency. It will be disclosed in United States-Patent No.- 1,892,645 noted that the diaphragm I0 is suspended beand-myself. In accordance with this patent, the and lower ends of the passageway.

diaphragm of a ribbon microphone is rendered As indicated by Fig. 4, the impedance chamber sensitive to sound wave pressure by placing may bein the form of a pipe"; flared at the end the opening of a pipe or conduit in juxtaposition adjacent the diaphragm and extending linearly .ture disclos y h P however is not ever, .lacks compactness and possesses other se- Suitab e o microphones h h ust be readily rious disadvantages where portability is an' im' portable such as thosesuspended from the coat portant c n5ideration lapel of a speaker. Having thus described my invention, I claim:

structure is simpl fied. the impedance presented means arranged to form a single chamber, an tothe ribbon di ph g being rendered independelectrical conductor forming a diaphragm and ent o q e y b m a Winding P mounted in said field to form a section in the y which 18 formed a the back wall of said chamber, means covering the rear of is enclosed within the magnetic structure 9 the way leading from said conductor and within said device' i chamber, and means located within saidpassage- The Principal b of-the invention is to way for renderingsaid conductor'responsive to the vide an improved microphone which operates in pressure of a sound tively light weight thus permitting-it to'be sus-..- means arran 7 ged to form a chamber, an electrifi ig gi i g g h user if desired" cally conducting diaphragm mounted in said field er Jec 0 e a r 1bbn micmphone to form a section in a wall of said chamber, means which is of relativelylight-construction. A furarranged within said chamber to form a winding v a l passageway with one of its openings covering the 35 whlch responds to sound wave pressure rear of said diaphragm, means within said .pas-

The invention will-be better understood from dag ent d the following description when considered in con- .ig fizg ggfi g giggggg fiii 23 53? 6 nection with the accompanying drawing and its 3. The combination of magnetic field producing means arranged to forms, chamber, an elec- 40 trically conducting diaphragm mounted in said field to formla section in a'wall of said cham-l Referring to the drawing: v,

. Fig. 1 is a partly exploded view of a microphone 'tit?223%itiiii iiiril 'iiiih...g he means. of mien-a1 a winding passageway or labyrinth inside the Filled passageway with one lts Open- 45 magnetic structure of thedevice, n gs at the rear of said diaphragm, means with- Fig. 3 is a plan view of the front of the device L passageway for rendefmgthe impedance I presented to the diaphragm independent of ire- Fig. 4 illustrates a modified'form of the invenquencyv tion which is satisfactory from the viewpoint of t 9i magnet: fi Pmdlmmg 5o 1 'fb but s less'satisfactoryl fro t means arranged to form a chamber, an electriviewpoint of compactness and portability. cally conducting diaphragm mounted i i field The device of Figs. 1 to 3 includes a corrugatedto form a section in a wall of said chamber, ribbon diaphragm l0 which is mounted in the means including a sheet of material loosely rolled field of a magnetic structure including a yoke H Y to form a passageway with one of its openings at 55 V 6. The combination of magnetic field producing means arranged to form a single chamber, an

electrical conductorforming a diaphragm mounted in said field, means arranged to form a labyrinthian passageway having its mouth adja- 5 cent said conductor and ieading into said chamher; and damping means located within said passageway.

V HARRY F. OLSON.

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