# JDS Labs OL DAC USB with bitperfect on FreeBSD?



## eldaemon (Apr 14, 2020)

I've looked through these threads:
 * https://forums.freebsd.org/threads/is-there-any-dac-compatible-with-freebsd.74463/
 * https://forums.freebsd.org/threads/oss-sound-quality.69335/

With dev.pcm.2.play.chans=0 and dev.pcm.2.bitperfect=0, playback of 44.1 and 48KHz files has a white noise sound in the left channel and sped up audio in the right.

Without bitperfect, it plays back fine.

I've tried mpv, which refuses to work. sox's play, mocp, and flac -dc > /dev/dsp2.0  all sound like how I described.

Any ideas?

Thank you!


----------



## mfoacs (Jul 1, 2020)

In my case, setting mixer ogain and igain to 0 solved the issue


----------



## eldaemon (Jul 2, 2020)

mfoacs said:


> In my case, setting mixer ogain and igain to 0 solved the issue



You have a JDS Labs OL DAC? I don't see the ogain and igain controls.


----------



## mfoacs (Jul 10, 2020)

What do you see when you run `mixer` without any arguments?


----------



## mfoacs (Jul 10, 2020)

I would suggest setting `sysctl hw.snd.verbose=4` and looking for the sample rates when bitperfect is active. A mismatch between the sound format and the device expected format would give you jitter, which could be the noise you're actually hearing?
You can also try setting `sysctl hw.usb.uaudio.debug=15`.


----------

