[LAU] Recording with TimeMachine

John Murphy rosegardener at freeode.co.uk
Sat May 16 00:55:53 CEST 2020

I've been using TimeMachine to record late night music radio programmes.
I'm pretty sure I didn't do anything different, but one recording is
significantly quieter than the others and the quiet one shows up as
of type 'Unknown (model/x.stl-binary)' in Nemo file manager, whereas
the good ones are of type 'Binary (application/octet-stream)'.

'file' says they are all Sony Wave64 RIFF data, WAVE 64 audio, stereo 48k

sox (-n stat) seems to show significant differences:

                         Good         Quiet
Samples read:         676507136     666574336
Length (seconds):   7046.949333   6943.482667
Scaled by:         2147483647.0  2147483647.0
Maximum amplitude:     0.999969      0.999969
Minimum amplitude:    -0.920116     -0.999969
Midline amplitude:     0.039927      0.000000
Mean    norm:          0.154645      0.051673
Mean    amplitude:    -0.000065     -0.000022
RMS     amplitude:     0.199364      0.066460
Maximum delta:         1.421344      1.754726
Minimum delta:         0.000000      0.000000
Mean    delta:         0.090457      0.034210
RMS     delta:         0.134921      0.048614
Rough   frequency:         5170          5588
Volume adjustment:        1.000         1.000

Any idea what could have gone wrong?

What would be the right way to calculate the value to use with sox -v
to get the volume level somewhere near that of the 'Good' recording?

Thanks, John.

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