The Reverberation Slope Ratio (symbolically T60SR6) is a proposed standard for condensing six octaves (63 Hz – 2 kHz) of reverberant decay data into a singular-quotient, qualitative score, for indoor performance, worship and entertainment facilities. It’s a defining metric for scoring and grading the proportional relationship (i.e. ratio) between the longest and shortest of six reverberation (T60) values, measured or predicted, and applied to fully-enclosed venues employing sound reinforcement systems. In practice, Bass Ratio (BR) and Slope Ratio (SR) goals are conflicting concepts. BR goals and calculations were developed to support the idea that acoustic instruments need a little extra assistance, via longer reverberation time, in the low-frequency range. SR goals and calculations support the notion that those same low frequencies do not require extra reverberation time, but rather need to be well contained. Longer low and very low-frequency reverberation is not needed, nor desirable, when an extended-range sound reinforcement system is used. The T60SR6 thesis is offered to advance and define a room’s acoustic design objectives, and provide a simple numeric scoring scale and grading vocabulary, from which acoustical design specifications can be initiated and/or evaluated.
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