Show NM huew aj U iwillor t by A W V whenever there was occasion to demonstrate a receiving set with a lou loud d speaker either in a large or small room to a number of 0 people where a comparatively large volume of sound had tobe to be used there was always met lale annoyance to those near the speaker of being disagreeably affected edwhite while listeners tit at n point half way to h he e rear 0 of the room would just about beable be able to judge tile lie good and bail bad P 0 ints of the receiving set employed at the present time when en 1 Is furnished in nn an dudl andl borlum hotel lobby etc it Is always i necessary necess ari to use two loud speakers f placed at d different iff e rent points from time to time now new loud speak I 1 era have been placed on the llie market however the manufacturer of every one males makes new claims only for quality of tone etc due to tile tho construction of the diaphragm in principles they are all alike throwing the entire volume of sound in id one direction k 4 beginning with the premise that even distribution of this volume of over the lie entire room in other words diffusion of the sound would solve the problem it logically follows that this must be tone done from some point at the center placing a loud speaker with the con vent lonal ional type of horn at this point II 11 directing the sound waves either against the coiling or the floor does docs not help skelp the problem was oue one of actual direction of the waves taking into consideration the reflecting ties of the horn itself as well as those of the ceiling cel ling walls vails and floors doors the solution had to be such that the K details detail and dimensions of the loud speaker horn described in this article the larger horn la Is sup ported by pieces ot of fiber fastened to the outer horn means sought would function under any indoor conditions such as in rooms of different sizes sites furnished or unfurnished etc prom from the tha above the line of research to bo be followed and the solution will be readily understood by bi the description and illustrations of the mhd means employed to zet the desired effect of diffusing the total volume of sound practically evenly over an intire entire room the first step was to place a horn within a horn with simple means to hold these two horns la in their proper relative positions sit att ions lons horna with straight sides would natural naturally lr constitute no improvement pro therefore the principle of the bell as a for instance the opening of it a cornet of tile the brass musical wind instrument was adopted and please note this bell has been used since time immemorial without change on the curve cue of the bell however depend to the largest degree UK the acoustical qualities and to fulfill its purpose tills curve lias has to be mathematically mati cally ns as well as acoustically correct and by collaboration the true curve was designed after after using various materials tile the horns were ninde made of no 10 range copper anil ani in order to still minimize internal vibrations the interior us as fur far as possible as well as tile lie exterior of both horns were covered with paper the illustrations show allow the dimensions as well as tile the curves it will be noted that the inner hum horn at the bottom Is shorter than the outer one and the travel of sound waves through tills this horn Is directed nil and spread the ceiling cel ling while the lare flare directs the sound waves from the outer horn sideways and downward this combination of bells or duplex horni replaced tho horn of the loud speaker no power amplification was 4 1 two horns horn are used with alth this athla ar ran rano gement ement the sound Is projected upward through the inside horn and that from the outside horn deflected downward by the curved edges of the larger one needed as the receiving set apt employed was provided with three stages of f dudlo using no tubes the loud speaker was placed within nn an electric eslit fixture of the reflecting bowl type and suspended in such manner that tile the top of the speaker would be within 4 la feet if the top of a room 32 12 feet high in rooms with lower ceilings approximately the same proportions weve maintained considering the fact that the bells in tills this speaker were ero by no means perfect each was made in two pieces cut out of a flat sheet of copper shaped by hand brazed and fInIs lied on man dhols which happened to be near the dimensions required the result was truly surprising in every part of tho the room be it directly underneath the speaker or at a distance of 15 feet tho the results were entirely different from those obtained with the usual type of horn lood good music or the voice received ce lied acquired or was reproduced reproduce din in a soft mellow tone though tho the full volume was used at the input and without this input being greater than necessary with the old type horn the above results were obtained in a room 28 by 35 feet using a single speaker it la Is a practical certainty certain tk that thai in a large auditorium with fair adir acoustical qualities two t V 0 or three loud speakers using the described type of horn will give excellent results naturally tests for placing tile the horns will have to be made in every case as the length width and helget liel glit of the auditorium will govern the situation only the horn of the size illustrated has been made and used Ilo however wever there should bt bno no question frown fron tho the acoustical standpoint why different sizes ot of double horns equipped with different types of should not work satisfactorily radio iladio news |