shift = 5
                data = stream.read(CHUNK, exception_on_overflow=False)
                da = np.fromstring(data, dtype=NP_FORMAT)
                left, right = da[0::2], da[1::2]
                lf, rf = np.fft.rfft(left), np.fft.rfft(right)
                lf, rf = np.roll(lf, shift), np.roll(rf, shift)
                lf[0:shift], rf[0:shift] = 0, 0
                nl, nr = np.fft.irfft(lf), np.fft.irfft(rf)
                ns = np.column_stack((nl, nr)).ravel().astype(np.int16)
		#index = delay_modification(data, buffer, index)

                stream.write(ns.tostring())