[LAU] Record levels lower in Alsa than Jack

John Murphy rosegardener at freeode.co.uk
Thu Nov 5 22:06:19 CET 2020

Wondering if there's a command line (scriptable) recorder for Jack
which will record for a configurable duration. Because:

I've been using Jack TimeMachine to record in its default 'w64' format
and then converting to wav with sox like:

sox --no-clobber -S tm-2020-10-27T22:00:15.w64 -b 16 /home/john/2710.wav

It all works well and sox stat shows min and max amplitude -0.9 and 0.9

I need to make the recordings automatic and arecord seems to fit the bill
with its ability to record for a number of seconds with -d, but the level
seems much lower. I used PulseAudio Volume Control to get something like
a good level with 150% on the input sliders (10.53dB) and I still only
see around -0.5 and 0.5 using sox stat. They only go up to 11dB.

I don't like pushing levels that far and it isn't enough anyway. Something
seems very wrong with Pulse / Alsa although Jack uses Driver: alsa.

PAVolume Control > Input Devices shows UltraLite AVB Multichannel
Port: Multichannel Input
Front Left    (where the inputs levels are)
Front Right                 "
6 other position channels (showing no input level)
16 Auxiliary channels               "

Thanks again,

More information about the Linux-audio-user mailing list