GB936449A - Improvements in or relating to sound reproducing arrangements - Google Patents

Abstract

936,449. Binaural systems. TELEFUNKEN G.m.b.H. Dec. 15, 1959 [Dec. 15, 1958], No. 42512/59. Class 40 (4). In a stereophonic reproducing system including two stereophonically associated amplifiers, low-frequency components of left and right hand signals are applied to one of the amplifiers together with high frequency components of one of the left and right hand signals, while only the high frequency components of the other of the left and right hand signals are applied to the second amplifier. Low frequency components or signals are audio frequency signals up to about 300 cycles/second. A cabinet houses a monaural radio receiver D, Fig. 2, and a stereophonic pick-up P. Stereophonically related signals from pick-up P are applied successively to preamplifiers V, to ganged switches S1, S2, to ganged volume controls L and to intermediate amplifying stages N1, N2. Low and high frequency signals from stage N1 are applied to output stage E1 Low frequency signals from stage N2 are applied by low pass filter F T to output stage E1 and high frequency signals from stage N2 are applied by high pass filter F H to output stage E2. Stage E2 has a lower power rating than stage El. Switch S1 may be set to pass monaural radio signals and provision may be made for passing such signals also through switch S2. The cabinet may house a loudspeaker H, Fig. 3, which may be connected to - either output stage as desired whereby, if the receiver is to be used only for monaural reproduction, loud-speaker H is connected to output stage E2. If subsequently the stereophonic facility is required, the loud-speaker is connected to output stage E1, a separate loud-speaker H2 being then connected to output stage E2. A receiver, Fig. 4a, having spaced high frequency loud-speakers H1, H2 has filter circuits which may be switched for feeding the low frequency signals of one channel into the output stage of the other channel, whereby the arrangement of Fig. 4b or 4c may be used. In these arrangements loud-speaker H2 receives only the high frequency signals of one channel while the high frequency signals of the other channel and the low frequency signals of both channels are received by main loud-speaker T12H1 and, if desired, by one or two loud-speakers h1. Alternatively the low frequencies may be handled by the main loud-speaker and the high frequencies by one or two high frequency loud-speakers h1.