.
Summing up, there is no doubt that omni-directional speakers or systems that specifically use walls for reflection do give a more spacious kind of sound. Under the right circumstances, one is less aware that one is listening to two loudspeakers. It is also true that this effect is achieved at the cost of definition. On the other hand, very directional loudspeakers give a sharp stereo image but the listening area is restricted. In the early days of stereo (two channel) I maintained that the optimum dispersion angle was 120 degrees but in these days of 16 channel mixers and multi-mic techniques I cannot be so dogmatic. Stereo itself is an illusion and the program material goes through many processes of mixing, dubbing, equalizing and so on. Some producers exaggerate separation, some transport the listeners to the conductor's podium and others try and give him the impression of being in the middle of the 10th row back.
Then again, most of today's music is recorded in the studios-not the concert hall at all! Finally, there is the question of room acoustics. The room must be considered acoustically as an extension of the loudspeakers and what sounds superb in one room can be incredibly bad in another.
Perhaps the best answer to some if not all of these problems lies with the intelligent use of the quadraphonic medium. This can give us a better sound image without relying on random room reflections or being so affected by room acoustics-especially standing waves.
Moreover, as Jim Long stated in his recent article on microphones, "Four mic/four channel recording reduces the need for accent microphones. The ability of four-channel stereo to sort out a single event amidst complex aural confusion--if the recording is properly handled--can be downright uncanny!" The big question will be: What kind of loudspeaker radiation pattern will give best results with quadraphonic sound? My own tests indicate a dispersion of 90 degrees but I am reserving judgment for the moment.
--G. W. T.
(adapted from Audio magazine, Mar. 1973)
Also see:
Quadraphony Needs Directional Loudspeakers (Mar. 1973)
Omnidirectional Radiation (in Acoustics) (Mar. 1973)
The Loudspeaker as a Spherical Sound Source (Mar. 1973)
In All Directions by John Crabbe (Mar. 1973)
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