I’ve been tinkering with this & Audacity and have this to offer to anyone who’s interested. I’m using Suse but …
http://www.trixtar.org/3/music/hardware/6fireusb/MDX6FireUSB-OpenSUSE.html
Note that this is NOT the same as earlier internal PCI models except conceptually.
Does anyone know of a dedicated mixer instead of the rudimentary alsa one for this “external” sound card?
I’m not too sure how to use them all together: 6Fire, jack, rosegarden, audacity
tia
Thanks for posting the information, and good to know that the DMX-6Fire-USB works on Linux.
When you have finalised where your page will be hosted it would be good if you could post a brief review and link in this section of the forum: http://forum.audacityteam.org/viewforum.php?f=27
Alsamixer is, as you say, rudimentary, but is very useful as it handles the sound card at “driver level” - that is, it is closely bound to the actual hardware rather than going through multiple layers of API.
Hardware → ALSA (drivers, including Alsamixer) → Gnome/KDE/PulseAudio/Jack
Unfortunately the lack of support by TerraTec is going to make setting up your system a bit tricky and fiddly (but I don’t want to knock TeraTec too much because they are one of the few hardware manufacturers to provide “some” support for Linux, which is to be applauded).
Jack Audio System is likely to be the way to go for getting the best out of this device. It offers low latency, configurable connectivity, and can (now) also work with PulseAudio and programs that are not Jack aware.
Audacity has limited (but definitely usable) support for Jack.
First the limitations:
Audacity does not support “Jack Transport Control” 
Audacity does not (fully) support the “patchbay” in qjackctl.
Enabling the Audacity record monitor before any recording has been done is likely to crash Audacity (a bug).
The Audacity recording/playback meters only have 2 channels (for mono or stereo).
Playback from Audacity is limited to a maximum of 2 channels.
Now the good news:
Audacity works very well with Jack (other than the above limitations).
The Audacity record monitor works correctly (without crashing) after recording has been enabled once.
Audacity can record multiple channels simultaneously into separate tracks.
The first thing to do is to see if you can get basic record/playback functionality in Audacity with Jack.
First you will need to start Jack - do this with Jack Control (qjackctl).
Launch Jack Control and open the “setup”. Ensure that the input and output devices are set to the DMX-6Fire-USB device.
As a first attempt, after checking/setting the input and output devices, try starting the Jack server using the “Start” button on Jack Control.
Getting Jack configured correctly can be the hardest part, but fortunately you don’t need to do this often - once you have it running properly the settings are saved and should work automatically the next time.
When Jack is running correctly Jack Control looks like this:
If error messages appear we will need to fix that before going further.
If Jack runs OK, then launch Audacity and set “Host” to “Jack Audio Connection Kit” in the Device Toolbar. Leave the recording input and playback output set to “System” for now. Try importing a file and playing it. Does it play back OK?
Try recording something plugged into channel 1 of the DMX-6Fire-USB does that record OK?
How are we doing so far?
I’ve used Audacity now with Jack but not with jack AND TerraTec-6Fire. That’s a coming insertion into the page I just updated.
When I set Audacity to use Jack the input & output dropdowns get locked to just “system”, I haven’t gone any further, thisi may be completely normal
Initially when Audacity is run with Jack the only option will be “System” - that is normal.
The hardware device will be the device that Jack is using, so to use Audacity with the DMX-6Fire-USB with Jack you need to use the “Setup” in Jack Control to set Jack to use the DMX-6Fire-USB.
Once you have that part working successfully we can look at the other things that can be done using Jack, but it is essential that this part is working properly first.
Hi Stratovarius,
I just found your thread here because I am also currently concerned with the 6fire and Audacity. I am the developer of the driver and someone contacted me recently because of recording from audacity. I also saw your manual for the 6fire which I find pretty good. In fact I’d like to offer help concerning questions about the driver and receive suggestions on how to improve the driver. In the near future I plan to revise the input channel routing system. There I’d appreciate some feedback from someone who uses the card intensely (more than I do). In fact, currently it is annoying that if you want to record from Phono, you have to record all 4 channels and discard the first two (this is what the guy - who I mentioned before - found out).
If you wish, you can contact me by E-Mail. My address is found on the sourceforge page in the driver.
Regards,
Torsten
Thanks everyone, I’ve been very busy but now have to make this work all over again. I will study the comments and get back during the coming weeks (I hope).
Meanwhile, because on revisiting my own page I couldn’t understand half of what I had myself written, I’ve started editing the page and have also relocated it to
http://www.trixtar.org/3/music/hardware/6fireusb/MDX6FireUSB-OpenSUSE.html
where it will stay for a longer period
later
Done editing & I got it set up on oss-12.2 on a g73 laptop. I’m pretty sure it’ll also work out on the desktop deathstar as well on every other machine, all moving up to 13.1. I also want to do it on Mageia instances.
THANK-youze go to Steve & Torsten. I’m a little curious why the DL’d firmware fails while the older stock windows version doesn’t but I probably won’t re-edit for another year now, much rather learn the guitar 
I’ll permit myself a small observation here, seein’ that soon 11 thousand reads will have hit my article.
This amount of passive interest says one thing and one thing only; namely, that a LOT of folk are having a LOT of difficulty making this work so I would suggest if I may that much of the dev. effort go in that direction. Probably a lot more ‘plain-english’ documentation with explicit examples would be a good idea to consider