2010/2/16 Lennart Poettering <mznyfn@xxxxxxxxxxx> > Heya, > > a while back I wrote a little tool "dbmeasure" which can be used to > determine dB attenuation data for alsa mixer controls. I have now > extended this little dB tools suite to include a tiny tool "dbverify" > that can be used to verify the correctness of existing dB data exposed > by the drivers. It should be relatively easy to use that tool, > suitable even for non-guru folks who want to debug the dB information > from alsa. > > http://git.0pointer.de/?p=dbmeasure.git > git://git.0pointer.de/dbmeasure.git > > Just run "make" in a git checkout and then try: > > $ ./dbverify Aureon51MkII Master 30 200 > > That will verify the dB data of the "Master" control of the sound card > that goes by the id "Aureon51MkII". It will compare the discrete > volume steps 30 and 200: first it will play a full amplitude sine wave > at mixer volume step 30, and then will change to mixer volume step > 200, but attenuate the sine wave in software compensating for the > volume change. So once you hear the sine wave attenuated by the hw, > and once by the software. If the card's dB data is correct both sines > should have the same volume. > > > Lennart > > Finally have time and an analog loop back cable to test your program dbverify.c It really depend on your ear to do the verifcation which is not really scientific Unfortunately , I am unable to run dbmeasure on both of my au8830 and HDA sound card Can you provide any test result of your HDA sound card ? !) The program dbmeasure.c seem underrun easily since you start the device and waiting for the user to press enter key 2) it expect the sound driver can provide exactly 1 second buffer because your logic is generate one second sample, Neither au8830 nor HDA driver can provide exactly one second buffer _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
