GB1399846A - Artificial reverberation device - Google Patents

Abstract

1399846 Reverberation systems AKG AKUSTISCHE U KINO-GERATE GmbH 26 March 1973 [29 March 1972] 14500/73 Heading H4R Two identical electromechanical transducers coupled via a delay element having a non-uniform propagation property are arranged in a differential circuit to which an input signal is applied and from which an output signal is taken which is equal to the difference between the electromotive forces arising in the transducers, each transducer acting as both a transmitter and receiver, thereby producing a non- periodic reverberation effect. In a first embodiment two moving coil or rotary magnetic type transducers R, R<SP>1</SP> having matched impedances are coupled by a non-uniform torsional spring 2 and the transducers are arranged in a bridge circuit with two identical resistors R1, R2. The difference output signal U2 is obtained across one diagonal of the bridge and the input U1 is applied to the other diagonal. A similar alternative bridge arrangement is illustrated in Fig. 2 (not shown) and an arrangement using a differential transformer in Fig. 3 (not shown). In place of the torsional spring arrangement a two dimensional delay element such as a thin plate 4 may be used on which the driving transducers are mounted symmetrically or alternatively a three dimensional enclosed air space having two transducers each acting as microphones/loud-speakers, mounted therein may be used, the circuitry being as for the torsional spring embodiment.