US1851208A - Art of sound reproduction - Google Patents

Description

March 29, 1932.-

A. McL. NICOLSON ART OF SOUND REPRODUCTION Filed June 20, 1927 3 Sheets-Sheet l INVENTOR ALEXANDER MLEAN NICOLSON March 29, 1932. Mc| c s 1,851,208

ART OF SOUND REPRODUCTION.

Filed June 20, 1927 3 Sheets-Sheet 2 INVENTOR ALEXANDER McLEAN NICOLSON 5, 7M5,

ATTORN EY March 29, 1932. A. McL. NICOLSON ART OF SOUND REPRODUCTION Filed June 20, 1927 5 Sheets-$heet AMPLIFIER DETECTOR R.F. AMPLIFIER.

INVENTOR ALEXANDER McLEAN NICOLSON BY 4 2 ATLI'IORNEY Patented Mar. 2 9, 1932 & UNITED STATES PATENT OFFICE ALnxAmma ucLnAn NIGOLSON, or NEW iroax, N. Y., ABSIGNOB 'ro COMMUNICATION rArmrrs, me, or NEW YORK, n; 1., A conroaArron' or DELAWARE ART 01 SOUND REPRODUCTION Application filed June 20, 1827. Serial No. 199,885.

This invention relates to electrical and acoustic apparatus and more particularly to apparatus adapted to reproduce at any desired volume sounds corresponding to eleca trical oscillations, which electrical oscillations may be currents derived from received wireless or radio signals, speech currents from a tale hone line, audio frequency currents or radio frequency oscillations modulated at 30 audio frequencies as produced by electric phonograph apparatus or the like.

One of the difliculties of radio reception 1n the past has been that of providing comfortable audition of radio signals for one who desires to hear them without disturbing others in the vicinity who may not wish to listen: for example, one may desire to listen to incoming radio signals at a late hour when persons are sleeping in adjoining rooms, or in the case of sickness where quiet is essential. Under such circumstances in the past, it has been necessary for the person listening to such -signals to utilize the socalled head telephones if quality of reproduction was desired. As is well known, head telephones are uncomfortable if worn for any considerable period and it is usually the case that if one member of a household desires quiet it becomes necessary to dispense with radio reception during such period. It has been attempted by listeners under such circumstances to obtain loud speaker reproduction by the use of a volume control to decrease the intensity of sound radiated to such value that it might be comfortably heard by the listener but without disturbing others. However, as is well known, it is not possible under such circumstances to obtain satisfactory quality of reproduction of speech or music, for the reason that when the volume is turned down to such a point that it is inaudible to those in the vicinity who do not wish to listen, it is usually inaudible to the person desiring to listen, or if not inaudible, the low frequency response is largely lost and the quality of the sound is distorted, the reason apparently being that the low frequency sound waves require a large amplitude of motion of the loud speaker diaphragm in order to be propagated any distance from the loud speaker, and such amplitudes are not REISSUED obtainable when the volume is decreased to a point such that the high frequencies are audi le for only a short distance. It results, therefore, that in order to hear music or speech of good quality, the listener must place his ear or ears in extremely close proximity to the speaker, and this close proxlmity is not obtainable comfortably with the present types of speakers. 1

It is an object of the invention to provide such apparatus which will allow the approach of the ear or ears in intimate and comfortable proximity thereto, and including, if desired, means whereby the operator'or listener may reduce the volume to a point such that the sounds produced'are clearly and comfortably audible to him with his ear-or ears in proximity to the sound reproducing apparatus, but of insuificient intensity to be card at any substantial distance therefrom.

It is still a further object of my invention to provide radio receiving and sound radiating apparatus which may be enclosed within a soft resilient comfortable covering having minimum sound absorbing properties, whereby the apparatus may-be used as a pillow, cushion or the like, to permit of the comfortable observation by the listener of the desired sounds clearly audible to him but inaudible to others in proximity to him, without the necessity of wearing head telephones, which covering may include within itself all apparatus necessary for the reception, selection, amplification, detection and reproduction of radio or like signals at the desired volume, or any desired part of such apparatus.

It is a further object of this invention to provide apparatus of the class described and 1 claims. My invention itself, however, both as to its fundamental principles and as to its practical application will best be understood by reference to the specification and accompanying drawings, in which:

Figures 1, 2 and 3 are diagrammatic views in partial section of various forms of sound reproducing apparatus enclosed within a soft resilient covering in accordance with my invention, and including sound reproducing apparatus and means for controlling the volume of sound reproduced, and Figure 1a. is a detail diagrammatic view of a suitable .volume control.

Figure 4 illustrates a slightly different form of supporting frame for the resilient and yielding envelope.

Figure 5a is a top plan view partly broken away of an arrangement in which the framework is dispensed with, and Figure 5b is an elevation view partly in section thereof.

Figure 6 illustrates a similar arrangement but enclosing within the covering a simple form of radlo receiving and detecting apparatus.

' Figures 7a, 7 b, and 7 c are respectively circuit diagrams of the apparatus shown in Figure 4:, and details of the control mechanism.

Figure 8 is a diagrammatic view of a system in accordance with my invention in which the sound radiating apparatus is enclosed within the covering and adapted to receive by inductive or capacitive coupling audio frequency currents corresponding to received radio signals and the like.

Figure 9 is a similar view of a slightly modified form of apparatus.

Figure 10 is a diagrammatic view of a still further modified arrangement which may be used in accordance with my invention.

In accordance with my invention, I provide sound reproducing and radiating apparatus such as a cone, horn, or sounding board, or a plurality of such devices, adapted to be driven by any suitable mechanism, such for example, as an electro-magnetic or electro static receiver or a piezo-electric device such as a crystal of Rochelle salt, and I enclose this sound radiating apparatus within a covering adapted to support on its outer surface of a layer or resilient and flexible material. The layer of resilient and flexible material is preferably made up of a substance or substances having minimum acoustic damp-- ing properties, and supported in a suitable manner by an open grille, mesh or similar structure, so as to interfere as little as possible with the radiation of sound, while affording suflicient rigidity to protect the apparatus enclosed within it.

I also provide a volume control which may be in the form of a variable resistance shunted across'the reproducing apparatus whereby the listener maycontrol the volume of sound reproduced, at will.

In accordance with one aspect ofmy invenattached to the covering. Under certain con-.

ditions, this pick-up device may be in the form .of a closed or open circuit adapted to be coupled inductively or capacitively with similar circuits carrying currents of acoustic frequency, and supplied by the output circuit of the radio receiving apparatus, electric phonograph apparatus, telephone line or the like.

11 accordance with still another modification of my invention, the pick-up device instead of operating at audio frequency, may operate at radio frequency or carrier frequency, to pick up electrical oscillations of such frequencies radiated either directly from a transmitter or secondarily from a receiver adapted to receive such oscillations and to retransmit or reradiate them at the same or difierent frequencies..,

The pick-up device in accordance with the simplest form of my invention adapted to operate at other than audio frequencies, may comprise a simple tuning system, a crystal or other detector, andsound reproducing apparatus as previously described.

In another form of my invention, such pick-up device may comprise a radio frequency amplifying system, either tuned or untuned, and the desired detecting and audio frequency amplifying apparatus as well as the sound radiating apparatus.

Referring now more particularly to Fig. 1,

have shown an arrangement of sound reproducing apparatus in the form of a pillow: in this ararngement, 1 represents a main frame ring of metal, metal tubing, wood, or the like, having the basic shape of the pillow: if a round pillow is desired, the frame or ring 1 may be circular: if a rectangular pillow is desired, the ring l ma be given the appropriate shape. Mounte within this frame or ring 1 isprovided, in this instance, a conical diaphragm 2 of suitable material, such as paper, reinforced fibre, or the like, secured to the ring 1 at its periphery by means of an annular hinge 3 of flexible material, such as cloth, paper, leather, or the like. Suitable brackets, braces or cross arms 4, may extend inwardly from the ring 1 to some interior point suchas the center for the purpose of suporting a suitable driving mechanism 5 for operating the diaphragm by means of aconnection 6. The driving mechanism 5 may be an electro-magnet of the usual type, or it may comprise an electro-static driving mechanism,

- cient strength,

or a piezo-electro crystal device of the types i iii f t tin th or e urpose r0 ec e aphragm and the mechanism conta med withm the pillow, and also for the pu use of proriding a firm foundation upon w ich may be built a yielding and resilient surface, I provide a pair of cover members 7 and 8 adapted to be secured in position on opposite sides of the r' 1. The cover members 7 and 8 are prefers 1y constructed in a manner to provide the necessary or desired mechanical rigidity while at the same time interfering as little as ossible with the radiation of the sound from 'aphragm 2. For this urp'ose, these members may be built up 0' wire mesh of sumrforated metal plates, wicker work, or the e, aiiording relatively large mechanical strength while at the same time presenting minimum impedance to the passage of sound waves therethrough. In order to provide for a resilient and yielding sur face, the members '2 and 8 may be, covered with a layer of cloth 10a such as cheese cloth, muslin, or the like, afiording a bed upon which may be built a layer of resilient and sound conducting material 9.

In order to obtain the best results, the layer of material 9 should be sufliciently thick to provide a yielding and resilient surface against which the ears or other members of the body of the listener may be reposed in comfort, while at the same time, this layer of material should not introduce any considerable damiping upon the sound waves, at any acoustic equency. Various materials may be used for this purpose, but I have found that the most satisfactory material is ever green foliage, such as balsam, hemlock or arbor vitae, pine needles, and the like. The theoretical explanation of the superior results obtained from this material in comparison with other materials, is not entirely clear, but is probably due to the fact that evergreen foliage in quantity between spaced surfaces of cloth or similar material, provides a relatively resilient and yielding structure, in which the free spaces of air are relatively large and in which sound may travel freely, almost as in free air, whereas in the case of materials in which the air spaces are relatively smaller and are more completely filled withmaterial, free movement of air pressure therethrough is thereby hindered or prevented. At any rate, whatever the theoretical explanation may be, I wish to note the fact that best results are obtained with the materials specified.

After a layer of the desireddepth of such material has been built up, for example 1" or 2" in thickness, an outer covering 106 may be attached, and finally if desired, an ornamental or decorative cover may be applied over all, the ornamentation or decoration being chosen to suit the taste and to harmonize with the setting in which the apparatus is to be used, without interference mth the tree passage of sound.

For the purpose of controlling the operation of the device, leads 11 and 12, through which currents of audio irequency are an plied to cause operation of the device, may provided with a suitable by-pass l3, herein diagrammatically shown as resistance, but it I will be understood that an inductance and capacity or any combination of those, may be provided. A suitable control for the by- 13 is extended to the exterior of the i ow, for example in the manner shown in igure 1a, wherein there is provided a resistance suitably mounted in the form of an arc and adapted to be traversed by a contact a 14 mounted upon a suitable shaft 15, in turn carrying a disc 16, to which cords or chains 17 are attached. Said cords or chains may pass through suitable o enings in the members 7 and 8 and the resi 'ent covering therefor and may terminate in obs, tassels, or the like, such as 18 and 19. In the operation of the device, the loads 11 and 12 are suitably connected to a source of audio freque cy currentssuch as the output of a radio r eiver a telephone line, an electric phonograph, or the like, which as will be readily understood, causes vibration of the diaphragm 2, thereb propagating sound waves through the resi ient and yielding cover into the open air. If a relatively large volume of sound is desired, as may be the case when several people wish to listen, impedance of the bypass 13 will be made a maximum by 0 eration of the controls: if, on the other and, one desires to listen without disturbing others,the impedance of the by-pass may be adjusted to such value that the intensity of the sound is diminished to the point desired: and it may be decreased to such a point that the operator may place his ear or cars in intimate and comfortable proximity to the diaphra m. 2 simply by reclining his head against t e pillow in the ordinary manner, and under such conditions the quality of sound radiated to the ear of the listener will be substantially the same as that radiated to the ear of the listener in 4 the usual manner. I

Referring now more particularly to Figure 2, I have shown a horn type-of reproducer 25 in place of the cone 2. By coiling the horn upon itself, it is possible to obtain a horn of relatively great length and wide frequency a response, with consequent improvement in quality, as is known in the art: in this instance, braces 26 may maintain the horn and operating mechanism in the desired position. As in the arrangement shown in Figure 1, a pair of supporting members 7 and 8 are provided over which is formed a layer of resilient material and the outside coverings, as already described. In addition, a suitable volume control may be provided having its controls extending outwardly through the outer covering as is also the case for leads 11 and 12.

Referring now more particularly to Figure 3, I have shown a similar arrangement except that in this instance the sound radiating element com rises a relatively large plain diaphragm. which may be a true diaphragm operating as such and constructed of any desired material such as metal, balsa wood, or the like, or may be sufliciently thick and so arranged as to constitute a sounding board.

Referring now. to Figure 4, I have shown an arran ement in which, instead of a framewor of wire mesh, or the like, I have utilized a pressed or formed member for example, of fibre, composition or the like, made in sections 7 and 8 as before, but provided in this instance with a depression on one side71 adapted to receive the head of the listener and also provided with a plurality of perforations 70 to permit free transmissions of sound waves therethrough.

While I have shown a lar e diaphragm as the sound radiator in this gure, it wlll be understood that other radiators such as those previously referred to may be used in this arrangement if desired.

Under certain conditions, it may be de-v sired to dispense with the supporting envelope, and such an arrangement is shown in Figures 5a and 5b. In this instance, I provide a horn 80, attached to the speaker unit, which horn may be mutilated to provide a dished portion 81 which maybe so constructed as to act as a sounding board, and also as a support for the flexible envelope. The horn 80 may be provided with a plurality of holes or openings 82 of any desired shape and disposition for the purpose of modifying the quality of the sounds reproduced, and of allowing free distribution thereof to the atmosphere. For the purpose of preventing the lling of the envelope from clogging the horn, the horn may be enclosed in a covering 83 of relatively thin and porous cloth such as cheese cloth, muslin or the like. A volume control will preferably be provided as hereinbefore described.

Referring now more particularly to Figure 6, I have shown a modified form of apcluded therein are complete in themselves and require no connection to outside circuits: In this inStance thereImay be provided in addition to the sound reproducing mechanism, a bracket or panel 30 supported from ring 1 which maycarry the usual elements of a simple radio receiving'set, such for example as inductance 31, capacity-32 and a crystal or other detector 33 which may be connected in the circuit shown in Figure 7 a: Antenna and counterpoise or ground conductors may be attached to the pillow in the form of ribbons, streamers and the like, or a suitable loop antenna may be formed within the coverin or otherwise attached thereto. In Figures a, 76, and 7c, 35 represents an antenna connected at one end of the coil 31; 37, a counterpoise connected at the other end of said coil; 32, a condenser in shunt therewith; 33, a suitable detector such as a crystal; 38, a by-pass condenser, utilized if desired; and 5 and 27 respectively represent the driving mechanism and sounding board as shown-in Figures 3 and 6. It will be understood that the arrangements shown in Figures 1 and 2, 4, 7a, and 7b may be utilized, or other suitable sound reproducing mechanism may be substituted for the arrangements shown.

For the purpose of providing for selectivity, coil 31 may be provided with a plurality of taps 31a, 31b, 31c, and 31d, arranged as desired, and adapted to be connected selectively in circuit by a suitable contact 10 secured to disc 41, and operated by means of pull chains 42 and 43. It will be understood that snap switches of any suitable type may be substituted, if desired, for the arrangement shown, or a continuousl variable inductance may be provided suc as a variometer. Similarly, the variation of the capacity may be obtained by providing a pluralit and 320?, adapted to be connected in clrcuit by means of a similar contact 40, the position of which is controlled b pull chains 42 and 43: similarly, snap switches may be of fixed condensers 32a, 32b, 32c,

substituted for the arrangement shown, or a continuously variable condenser may be utilized.

The arrangement of Figure6 will provide satisfactory reproduction of signals, from nearby broadcasting stations, particularly "when it is not desired to produce a large ing to a radio frequency amplifier, the outparatus in which the electrical circuit input of which is supplied to a detector and the detected currents from which are amplified by a suitable audio amplifier: instead of physically connecting the sound reproducing device to the output of the audio frequency amplifier, the output currents may be supplied to a suitable open or-closed circuit 47 which may be in the form of wires leading to any desired point, and to which similar wires included within the pillow may be inductively or capacitively coupled. This permits the movement of the pillow as desired without restriction dueto length of connectleadnond also permits the use of a pluty of speakers operated by the same reiver.

It me be dd to provide one or more stages or audio fre uency amplification with- Under certain conditions, it me be desired 1 to utilize e. lurelity of such pillows, each receiving on responding to a different tronsmitter: in such case, there may he provided redio frequency amplifying system edeed to receive and radiate signals at rec frequency, either on the same frequencies as r ived, or on difierent frequencies. For this purpose, there may be provided a redi= sting circuit d8 ntteched to the output of the emplifier: the amplifier itself mey1 comprise e. tuned system selectively emp et one frequency or en aperiodic amplifying sys empll g all incoming frequencies: or it may be in the form of e heterodyne which ma increase or decrease the frequency of a incoming signals by any desired amount, which new frequencies amplified if desired, may be radiated through the radiating circuit 48. The receiver in such case will preferably comprise a pick-up system with or without radio frequency amlification, a selecting system, a detector, and if desired an audio frequency amplifying apparatus. Such receiver may be utilized also to reproduce si als received from a radio phonograph as s own in Figure 9, WlllCh may conveniently comprise a thermionic vacuum tube oscillator 50 having an input circuit comprisin coil 51 and a condenser 52 provided if dzsired, with antenna 53 and counterpoise 54 of relatively small size. The input circuit may be connected between the cathode 55 and the control electrode 56, and an out ut circuit is connected between anode 57 and extends through a suitable feed back coil 58 and a microphone or magnetic pick-.

up 59 provided wit a stylus adapted to be driven by a suitable record. The plate oncult is completed through a suitable source of potential for feeding space current and heatmg the current to t e oscillator 60. As will be understood, the microphone or magnetic pick-up 59 serves to modulate at audio frequencies the radio frequency oscillationgeneratcd by the oscillator 50 which are radiated by the radiating system comprisin antenna 53 and counterpoise 54 and the ra iated oscillations are lcked up by the receiver, detected, ampli ed if desired, and converted into sound of the desired volume.

Under certain conditions, it may be desired to mount the entire apparatus comprising ravprising a layer 0 am lifier, detector, and audio or within the pillow so shown 1n Fi re 10, in which case a suitable loop may attached to the fabric, or ilarlysecured to the pillow or on open am tone and counterpoise circuit or ground may be provided in the form of streamers, hevin g metallic conductors provided therein attache to the pillow: in any event, the controls for volume and selectivity will preferably be pro= vided in the form of chains. cords or the like, extending out of the pillow, end eideer sufliciently inconspicuous esto be oticeable, or decoreted in e manner to harmonize with the decorative efiects thereupon.

While 1 have shown and described the devices herein as e pillow, it should be understood that my invention is not ited thereto but contempletes the provision of en upholstered envelope of any sort, whichmey be an article of furniture, such as e chair, end which includes in a recess therein, en ecous= tic radiating system, and also if desired, means for controllin the volume within any desired range: and a so any necessary or desired audio frequency amplifying apparatus, detecting device and a radio or carrier fre quency amplifying apparatus, together with the necessary pick-up devices.

While I have shown and described certain preferred embodiments of my invention, it will be apparent that modifications and changes may be made therein as will be understood by those skilled in the art, without departing from the spirit and scope of my invention.

I claim:

1. Acoustic apparatus comprising a loud speaker adapted to convert electrical oscillations into sound waves corresponding thereto, a protecting framework surrounding said loud speaker and a yielding and flexible covering having minimum acoustic damping characteristics mounted upon said framework.

2. Acoustic apparatus comprising an acoustic device adapted to convert electrical oscillotions into sound waves corresponding thereto, and a yielding dio uen fie ilfhy g1 evergreen foliage mounted upon said acoustic device.

3. Acoustic apparatus: comprising, in combination, a hollow flexible envelope, electrical sound reproducing apparatus positioned within sai envelope, and a layer of soft resilient material extending over the sound radiating portion of said reproducer, said material having a multiplicity of an spaces therein and permitting the passage of sound therethrough.

4. Acoustic apparatus comprising, in combination, a hollow flexible envelope, electrical sound reproducing apparatus positioned within said envelope, and a layer of soft, resilient material extending over the sound and flexible covering com radiatin portion of said reproducer, said material ing permeated throughout with air spaces Ipermittmg the passage 0 sound therethrou 5. coustic apparatus comprising a framework, a hollow yielding and resilient envelope of minimium acoustic damping characteristics, comprising alayer of evergreen foliage mounted upon said framework, and sound reproducing apparatus adapted to convert electrical oscillations into sound waves corresponding thereto, mounted upon said framework within said envelope.

6. Acoustic apparatus comprising an acoustic device adapted to convert electrical oscillations into sound waves corresponding thereto, a yielding and resilient covering having minimum acoustic damping characteristics mounted upon said acoustic device,saidyielding and resilient covering being arranged to completely cover said acoustic device to permit the ear of the listener to be placed in intimate and comfortable proximity thereto without contact with any hard object, and means for controlling the intensity of sound produced thereby.

7 Acoustic apparatus comprising a framework, a hollow yieldin and resilient envelope of minimum acoustic ampin characteristics mounted upon said framewor to permit the ear of the listener to be placed in intimate and comfortable roximity to said acoustic device, a loud spea er adapted to convert electrical oscillations into sound waves corresponding thereto, mounted within said framework and means for controlling the intensity of sound produced thereby.

8. Acoustic apparatus comprising an acoustic device adapted to convertelectrical oscillationsinto sound waves,corresponding thereto, a yielding and resilient covering having minimum acoustic d mping characteristics mounted upon said acoustic device to permit the ear of the listener to be placed in intimate and comfortable proximit to said acoustic device without contact wit any hard object, means for controlling theintensity of sound produced thereby, mounted within 'said covering, and a flexible operating control for said means extending through said covering.

9. Acoustic apparatus comprising an acoustic device adapted to convert electrical oscillations into sound waves corresponding thereto, a yielding and flexible covering having minimum acoustic damping characteristics,

enclosing said acoustic device, and means within said covering for suppl ing electrical oscillations to said acoustic evice without metallic connection to the source of such oscillations.

10. Acoustic apparatus comprisinga supportin framework an acoustic device carried trical oscillations into sound waves corresponding thereto, a yielding and flexible covsai framework adapted to convert elec-.

ering having acoustic damping characteristics mounted u on said acoustic device to permit the ear 0 the listener to be placed in intimate and comfortable prom'mity thereto and to be supported thereby, and means within said covering for supplying electrical oscillations to said acoustic device without metallic connection to the source of such oscillations, said. means comprising metallic conductors adapted to be con led with a circuit carrying the electrical oscillations to be supplied to said acoustic device.

11. Acoustic apparatus comprising an acoustic device adapted to convert electrical oscillations into sound waves corresponding thereto, a yielding and flexible covering having minimum acoustic damping characteristics mounted upon said acoustic device and means associated therewith, for sup l ying electrical oscillations to said acoustic without metallic connection to the source 0% such oscillations, said means comprising metallic conductors adapted to be cou led with a circuit carrying the electrical oscillations to be supplied to said acoustic device, and means for amplifying the oscillations produced in said conductors all of said apparatus being mounted within said covering.

12. Acoustic apparatus comprising an acoustic. device adapted to convert electrical oscillations into sound waves corresponding thereto, a yielding and flexible covering having minimum acoustic damping characteristlcsmounted on said acoustic device, and means associated therewith for supplying electrical oscillations 'to said acoustic device without metallic connection to the source of such oscillations, said means comprising metallic conductors ada ted to be coupled with a circuit carrying t e oscillations to be supplied to said acoustic device, a frequency selecting circuit, and means for amplifying the received oscillations, and flexible means for varying the operating characteristics of desired parts of such apparatus and extending through said coverm all of said apparatus being mounted within said covering.

13. Acoustic apparatus comprising an acoustic device adapted to convert electrical oscillations into sound waves corresponding thereto, a resilient and flexible covering having minimum acoustic damping characterisstics mounted on said acoustic device and means associated therewith for supplying electrical oscillations to said acoustic device without metallic connection to the source of such oscillations, said means comprising metallic conductors adapted to be coupled with a circuit carrying the oscillations to be supplied to said acoustic device, a frequency selecting circuit, a detector and means for amplifying the received oscillations and flexible means for varying the operating characteristics of desire parts of such apparatus and extending through said covering all of evice said apparatus being mounted within said covering.

14. Acoustic apparatus comprising in combination, a framework, audio frequency amplifying apparatus mounted thereon, a sound reproducer carried thereby and connected to said amplifying apparatus, and a resilient covering mounted on said framework over said amplifying apparatus and loud speaker to support the ear of the listener in intimate and comfortable proximity to said loud speaker.

15. Acoustic apparatus comprising in combination, a framework, radio receiving apparatus mounted on said framework, a sound reproducer carried thereby and operable by said receiving apparatus and a resilient covering mounted thereon over said receiving apparatus to support the ear of the listener in intimate and comfortable proximity to said loud speaker.

16. Acoustic apparatus comprising in combination, an electrically operable sound reproducer, a resilient and flexible covering extending over the sound radiating portion of said reproducer, and constructed and arranged to support the ear of a listener in intimate and comfortable proximity thereto, said covering comprising a resilient body permitting the passage of sound therethrough.

l7. Acoustic apparatus comprising in combination, an electrically operable sound reproducer, a resilient and flexible covering extending over the sound radiating portion of said reproducer and constructed and arranged to conform to and comfortably support the ear of a listener in proximity to said sound reproducer, said covering comprising a layer of resilient material permeated with air spaces.

Signed at New York city in the county of New York and State of New York this 8th day of June A. D. 1927.

ALEXANDER McLEAN NICOLSON.

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