Experiments and experiences in stereo

Abstract

A considerable number of observations as well as formal experiments in High Fidelity Stereo sound are reported. Three-channel stereo with corner flanking speakers has been shown to achieve accuracy in both tonality and geometry. A large center speaker with small outriggers is observed to lack both tonality and geometry. A center speaker in the corner with wall outriggers is observed to produce a deeply curved stereo geometry. Limiting speakers to a bass range down to 300 cycles may preserve geometry, but not tonality. Overly large bass speakers lead to a spatial and delay separation of bass and treble events. There is an optimum bass speaker size. Wide spacing of speakers offers improved accuracy of stereo geometry. The array cannot normally exceed the speaker spacing, but because of the focusing effect of the center channel, it may be much narrower than the speaker spacing. Numerous minor observations of radiation angle and polar response point up the desirability of corner speaker placement. Large speakers may be placed at low or high level, but the dynamic range of small speakers is limited. Corner speaker placement affects apparent room size and may be advantageously employed to improve the reverberation effects. Wide Stage Stereo demonstrations using speaker spacing up to 50 feet or more are compared to home applications with 15-foot spacing. High Fidelity Stereo is both high fidelity and stereo, and entails meeting the requirements of both.