US1599541A

US1599541A - Echo-box microphone

Info

Publication number: US1599541A
Application number: US703664A
Authority: US
Inventors: Nyman Alexander
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1924-04-02
Filing date: 1924-04-02
Publication date: 1926-09-14
Anticipated expiration: 1943-09-14

Description

Sept. 14,1926. 1,599,541

A. NYMAN ECHO BOX MICROPHONE Filed April 2. 1924 4 SheetsSheet 1 Fig.1.

WITNESSES: V A IQVENTRR 25 er Y I ATTORNEY A. NYMAN BCHO BOX MICROPHONE Sept. 14, 1926. 1,599,541

Filed April 2, 1924 4 Sheets-Sheet 2 Fig.2.

III

WITNESSES: INVENTOR A legancler Nyman. u v W Sept. 4 14 1926. 1,599,541

A. NYMAN ECHO Box mcaorabus Filed April 2. 1924 4 Sheets-Sheet 5 WITNESSES: I INVENTOR fl Alexander Nym'an.

' ATTORNEY A. NYMAN ECHO Box uIcao'P'nouE Filed April 2, 1924 4 Sheets-Sheet 4 v Fig.4.

wnusssss; INVENTOR Alexander Nymcm. I I B Q 7 ATTORNEY Patented Sept. 14,

UNITED. STATES.

PATENT ,oFF1cE.-

ALEXANDER NYMAN, 0] EAST ORANGE, NEW JERSEY, ASSIGNOB '10 WE BTINGHOUS E ELECTRIC & IANUFAOTUBUG OOIPANY, A CORPORATION 01' PENNSYLVANIA.

ncno-aox incnornoim.

Application fled April 2 My invention relates to apparatus for the translation of sound into vibrato electric currents, and particularly to directionally selective microphone devices.

One of the objects of my. invention is to cohstruct a device for convertin sound vibrations into electrical vibrations which shall respond to sound from certain sources more readily than from other sources.

Another ob "ect of my invention is to rovide sound-a sorbing and sound-shiel in means in connection with a micro hone an an attached electrical system whic shall respond only to sound from a predetermined source thereby generating a vibratory electric current which produces a much more truthful copy of the sound waves from the predetermined source when reproduced in a telephone receiver connected to the same electrical system.

In the development of the prior art of telephony, microphones have usually been" enclosed in a light metal case rovided with a small horn for collecting an transmitting sound to the diaphragm. Relatively few microphone devices have been constructed suitable for sounds other than speech and, in their construction, few attempts have been made to avoid response IIIJKI the microphone to extraneous sounds. e designers of such devices have placed much more'dependence upon the greater sound volume froma speakers voice when his face is in close proximity to the collecting horn, as compared with the volume of the extraneous sound preventing interference between its extraneous sound andspeech. The microphone then is sufliciently insensitive to be unresponsive to the lesser sound volume of the exgroup electrical 'secur traneous noises. v

Because of the lack of devices suitahle for the reception of sound from-substantial distances, the-collection of sound from a' of musical instruments, a chorus, and similar sound sources, and its conversion into vibratory currents, suitable for pu s such as that of modula a rad1osen g apparatus, have been. foun drflicult. Because of thislaclr, the broadcasting of vocal and instrumental music by a radio--' apparatus from a sound fpick-up by an ordinary telephone transmitter has been found unsatisfactory. Serious interference has been found to occur besendin 1924. Serial no. 103,064.

phone, it is necessary to distinguish between sounds of two types. Sounds emanating directly from the source to which response is desired may be called the primary sounds,

and echoes and other extraneous noises, in-

cludin applause and the ordinary sounds of an au ience, may be called secondary sounds. The purpose of my invention is to obtain a principal response by a microphone to pri- 7 mary sounds and a minimum response to secondary sounds.

My invention provides means whereby this preferential response may be obtained which consists of a mlcrophone mountin containing sound channels within its bo y. These sound channels are directed toward the source from which it is desired to receive the sound. The channels are formed from sound-absorbent material and are of substantial length. By this means, sounds from a direction included within an angle which subtends the sides of the channels is allowed to pass directly to the microphone and I affect it, while sound from sources not included'within this angle is caught and absorbed by the sides 0 the sound-conveying channel and thereby restrained from influencing the microphone.

, Other objects and structural details of my invention will be apparent from the following description, when read in connection with the accompanying drawings, wherein:

Figurel is a diagrammatic view of the device of my invention, as associated witha church choir, a choir screen, choir stalls and an organ, showing the device in. a typical location.

Fig. 2 is *a view, in. longitudinal section, of my device,

Fig. 3 is a view in section, of my device taken at right angles to Fig. 2, and

Fig. :1 is a per'spectivev1e w ofjhe device.

of my invention. V v

Fig. l'shows choir stalls 1, a choir screen 2, an organ 3, a choir arch 4 and a pick-up microphone 5. The microphone 5 is supported by the cords 6 and 7 which are attached to the walls of'the choir arch 4 at ioo hidden from the congregation by the choir screen 2, the microphone 5 being likewise hidden by the same means.

Referring to Figs. 2, 3 and 4, a microphone 5 comprises a sound-responsive element 11 that is supported by elastic cords within a containing envelope. This container com: prises a cylinder 13' of Micarta, fiber, metal, or other suitable material, and perforated at suitable points according to the position of the device with respect to the sound sources, to the output of which it is desired that the microphone respond. This cylinder encloses a series of concentric felt cylinders 14 to 19, inclusive. The ends of cylinder 13 are closed by

walls

21 and 22 of similar material which is faced with

felt disks

23 and 24. Supporting means 25 and 26, 27 and 28 serve to hold the felt cylinders in concentric positlon surrounding microphone 11. Other felt

discs

29, 31, 32, 33, 35 and 36 are provided within the interior of cylinder 19 supported by

means

25 and 26, 27 and 28.

Openings

37, 38 and 39, and 40 are also provided.

Circular hoops 43 to 46, inclusive, are also provided for maintaining the proper shape of the interior ofthe concentric felt cylinders. Hooks 42 are attached to the eX- terior of the cylinder 13 for supporting means. Referring particularly to Fig. 3, the sound-sensitive microphone device 11 is supported on elastic cords 12 within the containing cylinder 13.

Spacing means 41 are placed between the successive felt cylinders 14 to 19, inclusive, these spacing means being felt strips which are repeated about the axis of the cylinder at a 90 spacing.

In the construction of my device, I provide opening 37 to 40, inclusive, so disposed with respect to microphone 1 1 that,

when the assembly is supported adjacent to,

the sources of sound to which it is desired that the microphone respond, the openings are respectively directed toward these sources. These successive openings through the various felt cylinders are graduated in size and made to subtend an angle, with its vertex in the center of the microphone, equal to the angle which subtends the lines drawn from the center of the microphone to the boundaries of the space occupied by the sound source. This is indicated in Fig. 1 by lines 53 to 56 inclusive.-

This construction permits sound coming labyrinth of openings between the felt cylinders and are there absorbed and destroyed, by which means the secondary sound is prevented from affecting the microphone 11.

In Fig. 1, microphone device 5 is shown supported by cords 6 and 7. It has been found that loud organ music causes vibration of the entire structure of the building and such vibration, transmitted to a microphone, causes an objectionable rattling effect.- This ditficulty is avoided -by the supporting cords 6 and 7 which carry the weight of the microphone device and hold it in position butdo not transmit vibration to it.

In the operation of my device, I construct a sound-shielding means, as previously described, adapting the openings through the felt cylinders to the particular location in which the device is to be used. I then support the device so that the various openings are directed toward the respective sources which it is desired to receive, as shown in Fig. 1. I may then energize the microphone with electric current and it will respond to sound from the desired sources, since such sound is free to enter through the openings in the felt cylinders and impinge upon the transmitter.'

Sounds from other sources do not, however, enter the openings in such a way as to reach the microphone, but enter the labyrinth between the felt cylinders and are absorbed and thereby restrained from reachmg the microphone 11.

By this means, I am able to construct a shielding means which, surroundin a microphone, contains sound-conveying c annels adapted to convey sound from predetermined sources to the microphone 11, and am able to prevent sound from other sources from impinging upon microphone 11. In this way, I am able to obtain preferential response of the microphone 11 to primary sounds, as compared with secondary sounds.

VVhile I have shown only one embodiment of my invention in the accompanying drawings, it is capable of various changes and modifications without departing from the spirit thereof, including changes inan-- gles subtended by the openings through the felt cylinders and changes in the number of openings, as well as other changes, and it is desired, therefore, that only such limitations shall be'imposed thereon as are indicated in the prior art or in the appended claims.

I claim as my invention:

1. A directive reception microphone comprising, in combination, a sound-responsive device and a plurality of concentric perforated sound-damping elements surround ing said instrument.

2. A directive reception microphone comprising, in combination, a sound-res onsiv'e device, a plurality of concentric, per orated, sound-damping and sound-absorbing means surrounding said instrument, and spacing devices, said damping devices being space apart by said spacing devices.

3. A directive reception microphone device comprising a sound-sensitive device and a surrounding sound-absorbing device, said absorbing device being provided with soundconveying channels, said channels ,bein disposed to convey sound from certain irections only to said'sound-sensitive device.

4. A directive reception microphone device comprisin a sound-sensitive device, in combination with a sound-conveying device, said conveying device comprising a plurality of sound-absorbing containers perforated with a plurality of cooperating sound channels.

5. In a sound-responsivesystem, in combination, a microphone, and a surrounding plurality of sound-absorbent means having perforations constituting .channels leading to said microphone. v

6. .In a sound-responsive system, in combination, a microphone, and a, surrounding plurality of sound-absorbent means havingv perforations constituting channels leading to said microphone, said channels being directed toward the predetermined sources of sound. I

7. The combination of a microphone and a plurality of sound-absorbent means having a plurality of sound-conveying channels therein.

8. The combination of a microphone and a plurality of sound-absorbent means having a plurality of sound-conveying channels therethrough, said absorbent means com prising a plurality of perforated felt cyliners. I

9. The combination of a microphone and a plurality of'sound-absorbent means having a plurality of sound-conveying channels therethrough, said absorbent means comprising a plurality of perforated felt cylinders concentrically surrounding said microphone.

10. The combination of a microphone and a plurality of sound-absorbent means having a plurality of sound-conveying channels therethrough, said absorbent means comprising a plurality of perforated felt cylinders concentrically surrounding said microphone, said perforations forming said sound channels and being disposedsymmetrically with respect to a radiuscommon to all of said cylinders.

11. The combination of a microphone and a plurality of sound-absorbent means having a plurality of sound-conveying cliannels therethrough, said absorbent means comprising a plurality of perforated felt cylinders concentrically surrounding said microphone, said perforations forming said'sound channels and being disposed symmetrically with respect to a radius common to all of said cylinders, said common radius being directed toward the source 'of primarysound.

12. The combination of a microphone and a plurality of sound-absorbent means having a plurality of sound-conveying channels therein, said absorbent means comprising a plurality of perforated felt cylinders concentrically Surroundin said microphone, and felt spacing mem ers positioned between said felt cylinders.

13. The combination of a microphone, a plurality of sound-absorbent means, a container and supporting and positioning means, said absorbing means and said container having sound-conveying channels therethrough, said absorbent means comprising a plurality of perforated felt cylinders concentrically surrounding said microphone, said container coin rising a fibrousmaterial tube, said tube eing also perforated for said sound channels.

14. The combination of a microphone, a plurality of sound-absorbent means, a container and sup orting and (positioning means, said absor ing means an said container having sound-conveying channels therethrough, said absorbent means comprising a plurality of perforated felt cylinders concentrically surrounding said microlplhone, said container comprising a solid brous-material tube, said tube being also perforated for said sound channels, said perforations forming said sound channels and. being disposed symmetrically with re- (sipect to a radius common to all of said cyliners.

15. In combination, an auditorium in-.

eludin a part adapted for a program, a microphonea means associated with said microphone for hindering the arrival of sounds from certain directions, whereby the microphone is selectively sensitive to sounds from predetermined directions, and means for supporting the microphone and its associated means in such a position that the said predetermined directions are toward the art of the auditorium where the program isto be performed.

16. In combination, an edifice including a portion adapted for programs, a microphone, means for rendering the microphone selectively-responsive to sounds from a redetermined direction and supports exten ing from the walls of the edifice for maintaining the microphone and said means in such position that said predetermined direction is toward the portion of the edifice where the program is to be performed.

In testimony whereof, I have hereunto subscribed my name this 17th day of March,

ALEXANDER NYMAN.