US1935185A - Sound producing device - Google Patents

Sound producing device Download PDF

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Publication number
US1935185A
US1935185A US543341A US54334131A US1935185A US 1935185 A US1935185 A US 1935185A US 543341 A US543341 A US 543341A US 54334131 A US54334131 A US 54334131A US 1935185 A US1935185 A US 1935185A
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US
United States
Prior art keywords
valve
air
head
currents
seat
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US543341A
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English (en)
Inventor
Jurjen S High
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RCA Corp
Original Assignee
RCA Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to BE389124D priority Critical patent/BE389124A/xx
Application filed by RCA Corp filed Critical RCA Corp
Priority to US543341A priority patent/US1935185A/en
Priority to GB16477/32A priority patent/GB388269A/en
Priority to DER85131D priority patent/DE651418C/de
Application granted granted Critical
Publication of US1935185A publication Critical patent/US1935185A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/42—Combinations of transducers with fluid-pressure or other non-electrical amplifying means

Definitions

  • the valve seat is the locus ofa source, from a radio-receiver or from any appropriate a sink, and a throttle area, of which the ele-v source.
  • sink For the purpose of controlling the airments are enmeshed according to a sequence current, slidingvalves, poppet valves and valves indicated by the following notation: Sink,
  • Fig. 1 is a side elevational view of my improvision of) a valve-chamber which, at one side proved valve-mechanism for air-now loudof a movable valve-head, communicates with the speakers illustrating the connection thereto of atmosphere through a channel, the air-iiow reactuating means, s istance of which may be controlled to bias
  • Fig. 2 is a sectional view of the valve-mechavalve-head.
  • nismA taken along a line corresponding to the It is, furthermore, characterized by the fact line II-II in Fig.
  • valve-chamber accommodates a valve arrows, and seat wherein a system of linear, that is, slit- Fig.3 is an exploded view, in perspective, showshaped air-flow sources and a system of linear ing the laminated construction of the valve-seat.
  • an 105 yielded by the sources are operating in parallel air-flow loudspeaker constructed according to my ⁇ relation, as also are the air currents absorbed invention comprisesa valve-chestlwhich merges by the sinks.
  • the sink system cooperates in into the small end of an exponential horn 3 in series relation with the source lsystem, the which chest are included an improved valve-seat sources being enmeshed with the sinks and sepa. ⁇ 5 and. a Valve-head '7.
  • valve-head is conno nected to the vibratory element of a driving device 9 by means of a light, rigid rod 11 which extends through a stuffing-box 13 or packing gland provided with means, such as a washer 15 of soft rubber, or the like, for preventing air leakage.
  • the driving device, the valve-chest and the horn may be suitably supported from a rigid metal base-plate 17 and means are provided to permit moving the driving device, relative to the valve-chest, to provide for adjusting the armature clearance in the driving device.
  • the driving device may be carried by a plate 19 having a flexible portion 21, the end of the plate nearest the flexible portion being permanently affixed to the base-board and the other en'd thereof being movable with respect thereto.
  • a resilient washer 23 or the like may be disposed between the movable end of the plate and the metal base-plate and an adjusting screw 25 may be provided for urging the plate against the said washer.
  • the angularity of the plate 19 with respect to the base-plate therefore, is under the control of the adjusting screw and, since the relatively flexible armature is connected by the rod 11 to the relatively stii valve-head mounted upon the plate 17, the armature clearance may be adjusted by tightening or loosening the said screws.
  • the driving devices may be of any desired type capable of translating fluctuating electric currents into physical movements of the rod 1l extending to the valve-head, or the rod may be immediately or mediately connected to the styluscarrying arm of a phonograph (not shown). I have, accordingly, illustrated the driving device merely as a rectangle devoid of specific details.
  • the adjustment of the driver with reference to the valve, once established for a given input air pressure may be kept constant by a bracket or lock 26 whereby also microphonic effect and external audio feed-back is suppressed.
  • the system is stiffness controlled and the valve amplitude, at all frequencies below the natural period of the system, is substantially constant. Specifically, stiffness control is obtained by using a light valve-head in the valve and large restoring force in the vibratory system.
  • the initial valve-head lift at a given input air pressure is controlled for optimum operation by a mechanical and a pneumatic adjustment which will be indicated later.
  • valve-seat from a plurality of peculiarly shaped predominately flat lamin 27, 29, 31, and 33 which, when sweated together or otherwise held in correct relative position, define a plurality of air channels that reverse their direction in a common throttling chamber 35 one side of which is constituted by the valve-head 7.
  • the preferred shapes of the lamin, and the directions of flow of the air currents in the passages dened thereby, from an inlet port 37 to the common outlet conduit, will be self-evident upon an-inspectionof Fig. 3 of the drawings.
  • the lamin 33 it will be noted, are stream lined toward the common outlet conduit, or horn, for the purpose of reducing hiss and to permit each air-sheet to expand, exponentially, before it merges with the remaining sheets.
  • the assembly of the device is facilitated. They may, however, be cylindrical or otherwise curved, without departing from the spirit of my invention.
  • T have found it expedient to provide means for that purpose somewhat analogous tothe grid-leak resistor and biasing battery lutilized in connection with the use of a thermiomc tube as a detector.
  • Such means preferably, takes the form of an outlet conduit 39 extending to free air from the valvechest, through which, under control of an adjustable valve 4l, air is permitted to leak to an extent suliicient to maintain the average pressure behind the valve-head slightly less than the average pressure on the face thereof.
  • a conduit 43 communicating with the inlet port 37, permits the inlet air pressure to be observed and a reducing valve (not shown) may be interposed between the inlet port and the source of air supply for assuring the correct operating pressure.
  • the damping means may take the form of a layer 45 of sponge rubber or other material having the desired properties, which is pressed against the rear face of the valve-plate by an adjustable retaining plate 47.
  • the retaining plate is pressed against the rubber layer by the inner end of a cylindrical element 49 which threadedly engages an opening in the end 51 of the valve-chest and which is provided with a knurled knob 53 through which extends the valve-actuated rod 11.
  • valve-head clearance with respect to the valve-seat, is primarily adjusted by the screw 53 and by the bleeder-valve screw 41.
  • valve clearance is a function of (l) the magnitude of the input air pressure, controlled by a reduction valve (not shown), (2) the bias-pressure which builds up in the valvechamber, controlled by the bleeder-valve, (3) the pressure exerted by the damping means, controlled by the screw 53, and (4) the armature adjustment, controlled by the screw 25.
  • the combination of the adjusting means enumerated provides for optimum operation over a wide range of air pressures.
  • my improved air flow speaker is so extremely flexible that substantially perfect results have been obtained with pressures varying from zero to sixty pounds per square inch and h'igher.
  • the voice-current causes deflection of the valve-head which at maximum volume are of a magnitude of less than 1.5 mils in my present samples.
  • the incoming air current divides into a plurality of thin sheets which flow into the valve cham- Y ber, reverse their direction in the said chamber and now outwardly to the horn.
  • the face of the valve-head is, broadly speaking, the locus of reversal of flow of all the currents.
  • the average clearance between the valve-head and the valveseat being slightly more than one mil, is considerably less than the thickness of one of the air-sheets and the air, consequently, has greater velocity in the valve chamber than it does in the passage-ways defined by the lamin of the Self-oscillation, however, is primarily suppressed by the damping layer 45 which is pressed against the entire back surface of the valve-head by the adjusting screw 53 and retaining disk 47.
  • the throttling action of my improved valve is mainly due to viscous air-flow resistance in contradistinction to the predominantly turbulent air-ow resistance which is set up in the Parsons valve.
  • the modulation of air-flow by the variation of a viscous resistance produces a better tone quality than that obtained by variation of a turbulent resistance because, in the latter case, the tendency toward non-linear distortion and toward a reduction of the percent modulation at larger initial valve clearances is greater.
  • valve-head is rigid in construction. Valves of the type having a vibratory grill, as heretofore constructed, are rather delicate and easily damaged. My improved valve-head, however, being in the form of a rectangular or circular plate of aluminum or other light material, is substantially immune to damage during use.
  • valve-head surface and the valve-seat may be modified as to contour to give any desired type of response.
  • the valve-head may be provided with a plurality of rectilinear or circular channels of any desired contour and the ends of the lamina; between the inlet and outlet openings in the valve-head may be shaped to correspond to the channels.
  • the valve-head face adiacent valve seat 5 may be of any suitable material to obviate the chatter introduced by occasional over-loading, a feature which is substantially impossible of introduction into valves of customary type.
  • the valve mechanism is relatively inexpensive. It may be built up from sheet metal punchings soldered or brazed together and the size of the air channels is limited only by the thickness of the punchings. This feature is considered by me to be a radical improvement over valves of the customary type, since it enables more effective throttling without weakening the valve-seat structure.
  • valve bias chamber permits establishing acoustic counter-feed-back means to neutralize self-oscillation.
  • the valve can be operated at higher air pressures than customary and is, accordingly, self-cleaning.
  • the method of sound production which includes providing a plurality of separate air currents, causing said separate currents to flow in substantially the same direction in parallel paths, then causing the currents to combine and change their direction of flow, and throttling the combined currents at the locus of direction-change without completely stopping the flow thereof.
  • the method of sound production which includes providing a plurality of air currents, causing said currents to flow in substantially the same direction, then causing the currents to reverse their direction of flow, throttling the currents at the loci of their reversal and thereafter combining the currents.
  • the method of sound production which includes providing a plurality of air currents, causing the currents to reverse their direction of flow, constraining said air .currents to flow in thin sheets immediately before and subsequent to their reversal, throttling the currents at the loci of their reversal, and thereafter combining the currents.
  • the method of sound production which includes providing a plurality of air currents, causing the currents to reverse their direction of flow, throttling the currents at the loci of their reversal, thereafter combining the currents, and then permitting the combined air currents to expand exponentially into free air.
  • a sound-producing device comprising means providing a passageway for an air current and means for causing the current to substantially reverse its direction of flow between entering and leaving'said passageway, said last named means serving also to throttle the current in accordance with the sound it is desired to produce.
  • a sound producing device including a movable valve, a valve seat having a plurality of openings therethrough, inlet means communicating with certain of said openings and outlet means communicating with the remainder of said openings.
  • valve and valve-seat are substantially planar.
  • a sound producing device comprising means providing a plurality of inlet passageways for air currents, a valve-chamber communicating with said passageways, means providing a plurality of outlet passageways from the valve-chamber, and a movable valve-head disposed in said chamber and adapted to throttle air-currents in their passage through the said chamber.
  • An air-flow loudspeaker including a valveseat, a valve-head cooperating therewith, said valve head being of relatively light weight, and a vibratory system associated with said valve for providing a relatively large restoring force thereto whereby the valve head is stiffness controlled".
  • An air-flow loudspeaker including a valveseat, and a stiffness controlled valve head cooperating therewith, the natural period of the moving elements of said loudspeaker including the valve head being of the order of from 2500 to 5000 cycles per second.
  • valve-seat in which terminate a plurality of parallel inlet and outlet channels and a valve-head movably supported in proximity to said seat to define, with the valveseat, a common throttling chamber communicating with said channels.
  • the method of sound production which includes providing a plurality of separate air currents, causing said currents to combine and change their direction of flow, throttling the combined currents at the locus of direction-change without completely ,stopping the iiow thereof and then causing said currents to again change direction and to ow in separate paths.
  • a sound producing device including in combination, means providing a valve seat and a plurality of passageways terminating in said valve seat, a movable valve arranged in cooperative relation to said Valve seat to provide a passage- Way common to said iirst named passagewaysl and means for imparting a stiffness control thereto, including a compressed layer of damping material associated with the valve.
  • a sound producing device including in combination, an inlet port, conduit means for dividing an air current therefrom into thin lamentary air currents, a valve seat and a valve cooperating therewith to provide a passageway for simultaneously receiving, combining and reversing the direction of flow of said filamentary air currents, conduit means communicating with said passageway for again dividing said air current into thin lamentary air currents, and a common conduit into which said last named conduit means are arranged to discharge.
  • a sound producing device including a movable valve, a valve seat having a surface and a plurality of substantially parallel passages terminating in openings in said surface, inlet means communicating with certain of said passages and outlet means communicating with the remainder of said passages.
  • a sound producing device including a movable valve, a valve seat having a plurality of openings therethrough, inlet means communicating with certain of said openings and outlet means communicating with the remainder of said openings, the moving elements of said device including the valve having a natural resonance period toward the upper limit of the acoustic frequency range of sounds to be reproduced.
  • a sound producing device including in combination, means providing a valve seat and a plurality of passageways terminating in said valve seat, a movable valve arranged in cooperative relation to said valve seat to provide a passageway common to said first named passageways and means for imparting a stiffness control thereto, including a compressed layer of damping material associated with the valve, the moving elements of said device including the valve having a natural resonance period toward the upper limit of the acoustic frequency range of sounds to be reproduced.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Details Of Valves (AREA)
  • Golf Clubs (AREA)
US543341A 1931-06-10 1931-06-10 Sound producing device Expired - Lifetime US1935185A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE389124D BE389124A (enrdf_load_html_response) 1931-06-10
US543341A US1935185A (en) 1931-06-10 1931-06-10 Sound producing device
GB16477/32A GB388269A (en) 1931-06-10 1932-06-10 Improvements in or relating to sound producing devices
DER85131D DE651418C (de) 1931-06-10 1932-06-11 Elektromagnetischer Druckluftlautsprecher

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US543341A US1935185A (en) 1931-06-10 1931-06-10 Sound producing device

Publications (1)

Publication Number Publication Date
US1935185A true US1935185A (en) 1933-11-14

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Family Applications (1)

Application Number Title Priority Date Filing Date
US543341A Expired - Lifetime US1935185A (en) 1931-06-10 1931-06-10 Sound producing device

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US (1) US1935185A (enrdf_load_html_response)
BE (1) BE389124A (enrdf_load_html_response)
DE (1) DE651418C (enrdf_load_html_response)
GB (1) GB388269A (enrdf_load_html_response)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5936480B2 (ja) * 1976-02-10 1984-09-04 ソニー株式会社 スピ−カ装置

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Publication number Publication date
BE389124A (enrdf_load_html_response)
GB388269A (en) 1933-02-23
DE651418C (de) 1937-10-13

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