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Soundblaster Audigy 2 NX with ALSA
Introduction
This shortly describes how to get the Soundblaster Audigy 2 NX USB soundcard to work nicely under Linux with ALSA (http://www.alsa-project.org).
Basic installation
On current systems like Fedora Core 4 the card works out of the box in basic stereo mode. There are some smaller modifications needed to get it working nicely with 5.1 or 7.1 systems though
ALSA
First you should install ALSA at least version 1.0.9. The release candidates are not enough since most of the Audigy related patches where not included before the final release. Installing the newest ALSA version on FC4 is as easy as:
cvs -q -f -z3 -d ":pserver:anonymous:@cvs.sourceforge.net:/cvsroot/alsa" co -P alsa-kernel alsa-driver
cd alsa-driver
./cvscompile
make
make install
This will install the current ALSA from CVS for the currently active kernel. Note that you have to have the kernel-devel package installed! You can do this easily with yum install kernel-devel. For more information see http://alsa.opensrc.org/index.php?page=AlsaBuild2.6
Surround
Configuration
To get the surround sound working for data that is not available as surround file (like most mp3 files and the like, since the CDs you ripped only have got stereo available) add the following to /etc/asound.conf:
pcm.duplicate {
type plug
slave.pcm "hw:2,0"
slave.channels 6
route_policy duplicate
}
This will create a new PCM device that will duplicate the input to all 6 channels. Here I assume that the USB soundcard got assigned the third slot. On my notebook this is because I have an internal soundcard (device 0) and an internal modem that is supported by ALSA (device 1). You can check this by issuing cat /proc/asound/cards. The index is written as the very first element. Identify the Soundblaster card. The output will look similar to this:
# cat /proc/asound/cards
0 [I82801DBICH4 ]: ICH4 - Intel 82801DB-ICH4
Intel 82801DB-ICH4 with AD1981B at 0xc0000c00, irq 11
1 [Modem ]: ICH-MODEM - Intel 82801DB-ICH4 Modem
Intel 82801DB-ICH4 Modem at 0x2400, irq 11
2 [NX ]: USB-Audio - SB Audigy 2 NX
Creative Technology Ltd SB Audigy 2 NX at usb-0000:00:1d.7-4.3, full speed
So 2 is the index and thus I used "hw:2,0".
More information about this can be found at http://alsa.opensrc.org/index.php?page=FAQ028
Usage
To use this you now have to use "duplicate" as your playback device (instead of something like "hw:2,0" before). In XMMS for instance call the preferences dialog and set ALSA as the output plugin, configure it and set the playback device to "duplicate". It won't be in the list so you have to type it in! Other programs should have similar options.
Infrared
In new ALSA versions there is also support for the infrared remote. Support for this should be in LIRC 0.7.2. I have not tried this out yet. I will comment on this later when I tried.
Conclusion
The soundcard does work just fine, but there should be some more work on a useful default configuration. I'm sure we will see this in one of the coming ALSA releases. Have fun!
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