Double-slope decay makes a space sound drier than its T60 predicts

Evidence

In principle, provided we have an even exponential decay curve, the 60 dB reverberation is directly proportional to the earlier curves, and so this should not cause any problems. However, if the curve is of the double-slope form shown in Figure 6.15,then this simple relationship is broken. The net result is that, although the T60 reverberation time may be an appropriate value, because of the faster early decay to below 30 dB, we perceive the reverberation as being shorter than it really is. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1926

Categorization

• DEFINE: Pins down the difference between measured T60 and the perceptually decisive early decay time (EDT).
• XREF: Ties back to the earlier decay-curve discussion and the notion that measurements only capture part of what the listener experiences.