Патент USA US2145318код для вставки
Jan. 3l, 1939.- w. scHENK‘E-r A1.` > „ 2,145,318 ‘ IJOUDSPEAKER~ ÁRRANGEMENT y I med July 1o, 1937 v ' N WALT R A` ATTORNEY 2,145,318 -"Patented Jan. 31, 1939 PATENT OFFICE- UNITED STATES 2,145,318 LOUDSPEAKER ARRANGEMENT Walter Schenk and Waldemar Marthiens, Berlin, Germany, assignors to Telefunken Gesellschaft für Drahtlose Telegraphie m. b. H., Berlin, Ger many, a corporation of Germany _ Application July 10, V1937, Serial No. 152,916 In Germany July 14, 1936 (Cl. 179-1) 3 Claims. ums, on station platforms, in long halls, etc., in ' The invention relates to a loudspeaker arrange ment in which the individual loudspeakers are order to avoid lateral echo andecho-phenomena. equipped with sound conducting surfaces. With ’ In many cases it may be'necessary to avoid the arrangement there is obtained a preferably pronounced silent Zones at right angle to the_ 5 longitudinally extended characteristic of the main radiation. In accordance with a further E sound distribution in the direction of the axis of development of the loudspeaker arrangement ac cording to the invention, measures are taken the loudspeakers, while approximately at right whereby the air enclosed in the housing of the angle to the main axis of the loudspeakers sound should pass at a possibly low degree. It is known to impart to loudspeakers having 10 large surface diaphragms a certain directive ef loudspeaker arrangement can communicate with ` fect by attaching to the loudspeakers cone-shaped sound guides.` If the sound should be radiated preferably only in two directions for instance in 15 the same axis, two loudspeakers are set up of which the one radiates towards the one direction and the-other loudspeaker towards the other direction. the outer air. It is advisable to provide openings w in the walls of the housing whereby the sizeof said openings is possibly controllable, or else, shutter-like arrangements are built into the walls so as `to obtain a greater or lesser couplingv of the interior space with the outer air. Eventually, w the walls not having loudspeakers fastened there to may also additionally be adapted to open up or may open up as such. , Now it was found in such arrangements that, [email protected] especially when transmitting orders or commands, the low frequencies propagating spherically are noticed also outside the main direction of radi ation of the loudspeaker, so that desirable silent zones cannot be established, for instance when my, speaking in long halls, on station platforms, etc. In accordance with the invention a more favor ` With these arrangements the characteristic of the loudspeaker will be modified such that the @il 8-like shape will be widened out in the center so « that an elongated characteristic will be obtained. This entails the advantage that the transmission can be properly heard directly underneath the loudspeaker and in its vicinity. These control g5 arrangements at the housing have the further advantage that the range of the sound waves can loudspeakers equipped with sound guide, for in- » be influenced. The loudspeaker arrangement can be so oper stance in the form of a cone and radiating in able reproduction with large surface diaphragm 9,@ opposite directions, is obtained in-that the two systems are accommodated within a common housing. ‘ The air space enclosed in the housing causes ated that when using for instance two loud- ao speakers the diaphragms of the loudspeakers move both simultaneously outwards with respect to the housing. In order to obtain especially sharp ex a damping of the large amplitudes of _the dia m phragm and therefore predominantly a damping of the low frequencies. In this way the propagation of the low frequen cies particularly in the directions at right angle to the main direction of radiation will be reduced. tinction zones, the loudspeakers can be so con ¿m Laterally to the main direction, silent zones are obtained in which the sound is greatly reduced so that disturbances cannot occur. can be iniiuenced in wide limits. The directional characteristic of the loudspeak ers has the shape of an 8 in this arrangement. ,w The constricted part of the directional character istic lies practically on the center line between both loudspeakers. With such a characteristic of the loudspeaker arrangement it is now possible to set up a microphone in the direct vicinity of the 5U loudspeakers in the direction at right angle to the main direction of radiation without acoustic feed back taking place between the microphone and the loudspeakers. „ The elongated characteristic is of particular importance to the transmission of orders in stadi nected that one of the loudspeaker diaphragms gg moves inwards while at the same moment the other loudspeaker diaphragm moves outwards. With these different types of operation the range and the sound distribution of the sound waves In placevof a single loudspeaker, several loud speakers may operate on one or several cone shaped sound guide surfaces in the same direc tion. The figures show an example of construction of dt the loudspeaker arrangement in accordance with the invention. Figures 1, 2 and 3 show bottom, side (partly in section) and end (partly in section) views, respectively, of an embodiment according to the ao _ invention. Figure 4 represents directional char acteristics of the loudspeaker arrangement ac cording to the invention, and Figure 5 represents one of the possibilities of applying the loudspeaker arrangement according to the invention. an 2 > 2,145,318 In a housing I (Figures 1 to 3) the loudspeakers 5 and 6 are arranged in the obliquely disposed walls 3 and 4. Cone-shaped sound guides ‘I and 8 are disposed in front of these loudspeakers loudspeakers set up in the adjacent field. The lines I9 and 20 show, for instance, the radiation cone at right angle to the direction of the axis of the loudspeaker belonging to the loudspeaker having large surface diaphragms. The length o! the sound guides corresponds approximately to the length of the ordinary sound Walls. The In the example of construction the walls I2 and I3 are opened up at different degrees. sound guides 'I and 8 are likewise disposed ob liquely downwards. The loudspeaker and even 10 tually the sound guides may however also be ar ranged in the same axis. In the bottom 9 of the housing I one or more slots I IJ are provided which can be covered up to a greater' or lesser degree by movable plates or 15 bars II.~ In place of the slots to be covered also other means may be used, for instance, displace able shutters, slides, or the like. Furthermore, also the side walls I2 and I3 may beopened up t0 a greater or lesser degree independently of each 20 other. At the top of the housing a hook I4 is ar ranged from which the loudspeaker arrangementv con be suspended, or a hole may be provided in the bottom 9 of the housing I through which a mast may be inserted so that the loudspeaker can 25 be supported from the ground. Figure 4 shows directional characteristics of a loudspeaker arrangement according to the inven tion. The curve I6 at the loudspeaker arrange ment I5 shows schematically the characteristic 30 for an entirely closing housing. At the con stricted place of the characteristic IS a micro phone may be set up for instance at the place I'I. When opening the slots I0, or the side walls I2 and I3 the characteristic can be varied to such 35 an extent that for instance the characteristic I8 is obtained. Figure 5 shows the use oi the loudspeaker ac cording to the invention, for instance over oblique terrain such as found in open air stages or other arrangement when set up on an oblique line 2|. CII What we claim is: l. A loudspeaker system for controlling the di rectional radiation characteristic thereof, com 10 prising an enclosure provided with upper and lower walls, a pair of oppositely disposed side walls which are inclined downwardly and which have each a central aperture therein, and a sec ond pair of oppositely disposed side walls which are hinged at their upper edges, a pair of loud speakers arranged within the enclosure with each loudspeaker diaphragm mounted on its respective apertured side wall to permit the sound therefrom to radiate in substantially opposite directions, 20 and a horn member mounted on each apertured side wall external of the enclosure, the hinged side walls adapted to be separately adjustable whereby the space within the enclosure may be made to communicate with the outside air to a greater or less degree. „ ' 2. A loudspeaker system for controlling the di rectional radiation characteristic thereof, com prising a pair of loudspeakers disposed to radiatein- substantially opposite directions, a common 30 enclosure for said loudspeakers, a cone-shaped sound guide associated with each of said speak ers,l and adjustable apertures provided in the common enclosure, the extent to which the aper tures are opened determining the amount of 35 radiation in a direction at right angles to the main direction of radiation. 3. A loudspeaker system according to claim 2, wherein the common enclosure is provided with arrangements. By opening up the side walls I2 adjustable side walls whereby the space within and I3 the radiation cone of the loudspeaker ar » rangement can be influenced, and it is possible in this manner so to adjust the sound energies the enclosure may be made to communicate with the outside air to a greater or less degree. radiated by the loudspeaker that the field covered by this loudspeaker will not be disturbed by other WALTER SCHENK. WALDEMAR MARTHIENS.