music server

[linuxfan]

Oh, and to check whether your new configuration is working, run the alsamixer application, and move its sliders up and down. If you hear no change to the volume, that's good! It means that dmix has been successfully bypassed.

 

[Steve Graham]

linuxfan: Thank you for the Linux bit-perfect tips. I am still a newb here, so don't know how soon this post will get moderated. But again, thank you. Straightforward, which Linux always is.

 

[29285]

Interesting contribution. Linux sound has always been a mystery to me, specially the role of pulseaudio.

 

[linuxfan]

As I understand it, PulseAudio is another layer of sound processing, which needs to be avoided for bit-perfect playback.
I have never used PulseAudio (and don't wish to) but if you have it on your system, I believe you can disable it via the configuration file /etc/pulse/client.conf
to include this line -

autospawn = no

Or better still, use a Linux distribution which doesn't include PulseAudio !!

 

[phofman]

Oh, and to check whether your new configuration is working, run the alsamixer application, and move its sliders up and down. If you hear no change to the volume, that's good! It means that dmix has been successfully bypassed.

Sorry for intervening. The dmix plugin and mixer control elements are independent and have nothing in common. Mixer controls operate the soundcard's control facilities (volume, input attenuation, various switches), while dmix mixes multiple data streams into one for the plain output of the soundcard.

Therefore, alsamixer controls will work for the plain hw:X output with no dmix in the chain too.

Note 1) If 100% volume is wanted (i.e. bit perfection all the way to the DA conversion), it is possible to set the corresponding volume controls to 100% and lock them when opening the device in alsa configuration - that way no application will be able to change the setting.

Note 2) Technically, the default dmix involvement is configured in alsa default configuration located in /usr/share/alsa for cards not supporting hardware mixing (i.e. almost all).