Transaural acoustic crosstalk effect is a condition where some sound from the right-hand stereo speaker reaching the left ear, and vice-versa.
This is an active circuit that uses
first-order section to present a phase-shift filter with ft of 1kHz for
the quadrature signal and ft = 10kHz for the linear signal. It will
produce 90° phase shift between the quadrature and linear signals over the audio bandwidth of 1kHz to 10kHz.