Acoustical Parameters (ISO 3382)
After measuring an Impulse Response, this module makes it possible to calculate the Acoustical Parameters defined in the ISO standard 3382, in 10 octave bands (from 31.5 Hz to 16 kHz). These include various kinds of Reverberation Time (EDT, T20, T30, Tuser), Clarity C50 and C80, Definition, Center Time.
And now, the v. 4.0 of this module also computes IACC and the IACC-related parameters wIACC and Tau-IACC (from binaural stereo impulse responses), or the lateral fractions LE, LF, LFC (for stereo measurements having the omnidirectional signal on the left channel, and the figure-of-eight signal on the right channel).
Finally, the module can even employ a sound-intensity probe, deriving the pressure and particle velocity signals from it.
The calculations are made accordingly to the ISO 3382 standard: the impulse response is octave-band filtered by means of IIR IEC-compliant filters, then it is squared (for obtaining the acoustic energy) and processed. For the reverberation time estimation, the squared impulse response is backward-integrated, with an optional noise-removal algorithm. Then a linear regression is performed over the proper dB range.
For example, from the following binaural (stereo) impulse response:
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Pressing the button this user's interface appears:
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After selecting the proper options, pressing OK these acoustical parameters are obtained:
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The results can be saved in a file or exported to the Clipboard. Furthermore, if the user presses the button labeled "OK - keep processed", the currently selected octave-band filtered version of the original signal is obtained upon exiting the module.