[LAU] Pulseaudio Rants [WAS: Migrating to Linux - need help]

Niels Mayer nielsmayer at gmail.com
Fri Oct 1 17:41:16 UTC 2010

This seems to be a FAQ item.
See http://lalists.stanford.edu/lau/2010/09/0116.html

Summary: I believe pulseaudio should work by default with ice1712
cards and recent versions of ALSA if you ensure your ALSA definitions
(perhaps from an old ~/.asoundrc containing bad !default definitions
found on the net) aren't interfering with built-in support for this

In order for things to work  /usr/share/alsa/alsa.conf has to load, as does
/usr/share/alsa/cards/ICE1712.conf and the definitions setup can't be
interfered-with or bad things will happen across the board, including
a nonfunctioning pulseaudio -- which expects all these default names
defined for all cards.... With these setup (as happens by default in
recent ALSA versions) correctly -- have pulseaudio talk to the
/usr/share/alsa/cards/ICE1712.conf defined "default" or "iec958"

If "aplay -L" doesn't list the full expected set, then somethings
wrong. For a Delta66, for example you see:
    M Audio Delta 66, ICE1712 multi
    Default Audio Device
    M Audio Delta 66, ICE1712 multi
    Front speakers
    M Audio Delta 66, ICE1712 multi
    4.0 Surround output to Front and Rear speakers
    M Audio Delta 66, ICE1712 multi
    4.1 Surround output to Front, Rear and Subwoofer speakers
    M Audio Delta 66, ICE1712 multi
    5.0 Surround output to Front, Center and Rear speakers
    M Audio Delta 66, ICE1712 multi
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
    M Audio Delta 66, ICE1712 multi
    IEC958 (S/PDIF) Digital Audio Output

http://lalists.stanford.edu/lau/2010/09/0116.html goes into detail on the
"default" and "iec958" devices defined in
/usr/share/alsa/cards/ICE1712.conf . These ensure correct
bit-alignment and channel mapping from a world that normally talks to
16 bit soundcards with fewer than 8 channels. The envy24 uses oddball
S32_LE alignment as it's designed for 24 bit use and efficient PCI
transfers of that data; adding to the confusion, it presetns a card
with 10 output channels and 12 capture channels. That is what tends to
send misconfigured systems and pulseaudio into failure.


PS: this is all in theory, since I have deinstalled pulseaudio on my
system. However, I've experienced similar issues in configuring an
ICE1712-based card for "consumer" usage -- e.g. using a Terratec
DMX6Fire's breakout box headphone/mic connections for google talk
voice (works beautifully -- use the digital mixer to pipe-in your own
"on hold" music.).

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