[LAU] Record levels lower in Alsa than Jack

John Murphy rosegardener at freeode.co.uk
Tue Nov 10 14:15:27 CET 2020

Just wanted to say thanks again for the help with this. I've learnt:

Record levels are the same in Alsa and Jack and it was a normalisation
process which was making them look different (as well as how the levels
are shown in PavCtl are lower than in TimeMachine).

Normalisation loses nothing, but better utilises the available bit depth.

Cronjobs are easy to set up and this helps with the values:



My Bash script:


# folder to use

# duration (2 hours is 7200 seconds)
# add the date in the right format for the filename:
a+=$(date +%a%d%m.wav)

# start recording
jack_capture --daemon --channels 2 --port system:capture* -b 16 -d $d -fn $a

(I watched it make the connections in QjackCtl connections and
I even stayed up to watch it disconnect :) )


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