The apparent width of the sound stage can be varied in stereo systems by deliberately introducing cross-talk between the channels, part of the signal voltage of one channel being added to the second channel. The circuit shown in Fig. 18.6 provides continuous control between in-phase cross-talk of 100% corresponding to mono operation and anti-phase cross-talk of 24%. Greater anti-phase cross-talk is not required since the sound impression will fall apart for greater values.
The voltage gain of the circuit is 0.5. Input and output impedances are 750 kΩ and 47 Ω respectively, and the frequency response (–3 dB points) is from 20 Hz to 20000 Hz.