[alsa-devel] wrong decibel data?

[Nicolo' Chieffo]

This is what I'm doing:
- got a jack-jack audio cable
- connected the headphone to the mic
- open alsamixer and put everything to 0 dB
- verified that the pass-throw works by using the sound recorder

./dbmeasure plughw:0 dbmeasure_hw.log

exits with this error:

Iteration 1, level is 0 (-inf dB).
Volume level measured (0) was too high or too low.
Please adjust mixer so that initial level is between 0.8 and 0.97.
Test run canceled.


I've also tried to put the mic level at 100% (22.50 dB) but the output
is the same.