REW RT60 Data Panel

The values will be blank if there wasn't enough data in the filtered response to generate a result at the frequency. The orange values indicate poor line fit, so the results seem to be problematic through much of the low end. If you attach the mdat file can have a look at it.

In those measurements there are a couple of blank values for the 50 and 63 Hz octave fractions. That is because there is not enough decay curve to analyse before it reaches the noise floor. For the 63 Hz band in measurement 2, for example, the noise floor is reached after only 22 dB of decay. The minimum to generate data is 25 dB.


The room also does not look large enough for RT60 to be meaningful at frequencies that low, the decay is far from linear as it is dominated by the behaviour of individual modal resonances. The results are more consistent above a few hundred Hz, where the assumption of a diffuse soundfield which underlies RT60 measurement starts to become valid. At lower frequencies the modal behaviour will cause the results to vary significantly with the position of the microphone and the source.