I have two hardware mixing emu10k1 cards. Both machines are running Gentoo and both are dmix-free. Both of these are working great and they are easy to configure.

[u]SB Live! 5.1:[/u]

Use the default device for capture.

In alsamixer:

1) Unmute Mic Boost
2)Switch to capture view (hit tab or f4)
3) Make sure capture is enabled on "Mic". It should be in red and say "Capture" underneath. If it does not you can enable it with the spacebar
4) Make sure capture is also enabled on "Capture". Turn it all the way up.
5) Turn "AC97" up until the microphone is transmitting at the desired volume. Somewhere between 50% and 70% will probably be where you want it.

[u]Audigy 4[/u]

Use the default device for capture. If you use the "Mic Capture" device you will get a scratchy record effect.

In alsamixer:

1) Unmute mic boost/
2) Change "Mic Select" to the proper input (likely mic1)
3) Switch to capture view (hit tab or F4)
4) Enable capture on master and max the volume
5) Enable capture on "Mic" and max the volume
6) Increase the volume of "Analog Mix" until you microphone is transmitting at the desired volume. Somewhere between 50% and 70% will likely be where you want it.

This is a little different than the required configuration for other apps (Teamspeak and Mumble) but these options work 100% for me in mangler. If it is not working for you make sure that you are using the latest svn because a code change was required before either of these cards would work.

Thanks to Haxar for making this happen and thanks to the rest of the mangler team for a great piece of software.