DAFX: Digital Audio Effects, Second Edition

5.3 Basic Spatial Effects for Stereophonic Loudspeaker and Headphone Playback

The most common loudspeaker layout is the two-channel setup, called the standard stereophonic setup. It was widely taken into use after the development of single-groove 45°/45° two-channel records in the late 1950s. Two loudspeakers are positioned in front of the listener, separated by 60° from the listener's viewpoint, as presented in Figure 5.2. The setup of two loudspeakers is very common, though quite often the setup is not as shown in the figure. In domestic use, or in car audio typically the listener is not situated in the centre, but the loudspeakers are located in different directions and distances from him than in Figure 5.2. However, even then two-channel reproduction is preferred from monophonic presentation in most cases. On the other hand, in some cases the listener can be assumed to be in the best listening position, as in computer audio.

Figure 5.2 Standard stereophonic listening configuration.

This section deals with the spatial effects obtainable with such two-channel reproduction and simple processing. Two types of effects are presented, the creation of point-like sources, and the creation of spatially spread sources. More advanced methods for loudspeaker reproduction with HRTF processing are discussed in Section 5.4.5, which provide some more degrees of freedom, but unfortunately also ...