There is currently much interest in lateral reflections in concert halls. Attempts to quantify lateral reflections have, up to now, been limited. Lateral energy ratios have been measured using a bi-directional microphone. This technique lacks the resolution necessary to investigate direction other than side-to-side vs front-to-back. Also, discrete reflections are more and more being used to -tune- the acoustics of recording studio control rooms. Here again the direction of arrival is important. A new technique, known as the Polar Energy Time Curve, will be presented. Utilizing special software for the Techron TEF 10/12 analyzers, this technique extracts accurate directional information from either 4 or 6 Energy Time Curve measurements made with an ordinary cardioid microphone. The direction of arrival vs time or intensity of individual reflection s is displayed in polar form. The time, intensity and exact angle of arrival may be determined in any plane of interest. Three dimensional displays of energy arrival are also possible. Conventional lateral energy fractions, as well as other quantities, may be computed.
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