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Bedrock SMxx operating manual
© Bedrock Audio BV, 2019
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The signal-to-noise ratio (difference between the steady-state noise signal
and the system noise floor) is insufficient.
From the decay curves, three different reverberation time metrics are calculated:
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The EDT (Early Decay Time), based on the first 10 dB of decay
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The T20, based on the section of the decay curve between -5 dB and -25 dB
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The T30, based on the section of the decay curve between -5 dB and -35 dB
Each of these three metrics has its own linear decay curve fit through the data points. The
values of the EDT, T20 and T30 can be seen on the second screen of the RT60 module.
Note that the reverberation time usually differs significantly between different frequency
bands. Also note that (although respectively measured over 10, 20 and 30 dB of decay) the
values of EDT, T20 and T30 are always extrapolated to 60 dB of decay; hence the name
T60: the time it takes for the energy to decay to a level 60 dB below the starting level.
Cycle through EDT, T20 and T30 using the button on the right. Note that each of these
three metrics is always calculated and saved for each measurement, even if only one metric
at a time is displayed on the screen at a time.
RT60 measurement results.
Quite often, a single RT60 measurement is insufficient to obtain a stable result. Many ap-
plication standards require that data from multiple measurements are averaged. Sometimes
the position of the noise source and/or measurement microphone must be changed in be-
tween measurements.
The averaging of multiple measurements is supported in the following way:
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When browsing through save measurements (in the “browse measure-
ments” screen), you will see the mean data from each measurement series.