The Influence of Antiphase Crosstalk on the Localization Cues in Stereo Signals
P.M. Boers · Journal of the Audio Engineering Society · 1983
Widening of the stereo base is an attractive feature for stereo sets with closely spaced loudspeakers. This effect is brought about by the introduction of crosstalk in antiphase between the two stereo channels. An analysis of this phenomenon must be based on the directional localization cues of human hearing. The most important cues are lnteraural differences of level, phase delay and group delay. We show that the localization directly in front of the loudspeakers is determined by the interaural time delay differences only; to either side of thi_ position interaural level differences play a part too. At some positions, however, level effects and time delay effects provide conflicting localization cues, leading to a rather vague image of a virtual 8ource. Listening experiments were carried out to verify these results. From this investigation it follows that the introduction of a small time delay in the crosstalk circuit shifts the regions with reinforcing localization cues in the direction of the listener, thus improving the localization of virtual sources in the widened stereo image. 1.INTRODUCTION Stereo sound reproduction from two loudspeakers in a standard stereo set-up may create virtual sources at every position between the loudspeakers, i.e. the stereo base. Lauridsen and Sehlegel [1] found a way to widen the stereo base beyond two closely spaced loudspeakers. They use an arrangement that allows for crosstalk in antiphase between the two stereo channels. Hanson and Kook [2] state that at equal distances from two loudspeakers radiating in antiphase the intensity must show a minimum. By means of a phasor model Bauer [3] shows that signals in antiphase from two loudspeakers produce a phase difference between both ears of a listener positioned in the middle. Tappan [4]