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Mixxx doesn't directly support recording yet. But there are plenty of external applications that can do it for you. Audacity is generally a good open-source choice and has excellent editing capabilities to help you clean up your recording afterwards.
The upcoming 1.6.0 release will contain excellent support for the Hercules DJ Console Mk2. The Hercules is a portable little controller with a slick pair of jogwheels that's a perfect match for Mixxx. If you're looking for something cheaper, the Hercules DJ Control MP3 offers the same control surface, but without the built-in soundcard.
A complete list of tested hardware devices is available on the Hardware Compatibility page.
Update: Mixxx 1.6.0 includes support for multiple soundcards, meaning you can have the headphone output coming out of one soundcard and have the master ouput going out another soundcard.
Mixxx 1.5.0 doesn't support multiple output devices that span different soundcards. For example, if you have two soundcards, you cannot currently use one soundcard for headphone cueing and the other for master output. However, you can use multiple outputs on a single soundcard. For example, if you purchase a 5.1 USB soundcard, you can use the “front” output as your master output, and plug your headphones into the “rear” output for cueing. This is what the majority of Mixxx users do.
Yes. The trick is to force Mixxx's master output to playback the left/top track, and the headphone output to playback the right/bottom track. (Each track will come out a separate output, suitable for plugging right into an external DJ mixer.) The way one does this is by sliding Mixxx's crossfader all the way to the left, and turning on the headphone cue for the right channel. This forces the first track to play out the master out, and the second track to play out the headphone out. (Since both outputs are now going straight into an external mixer, you'd use the headphone cue on the mixer as well as it's crossfader.) Using an external mixer is also described briefly in the Threadbox tutorial.
When no soundcards/devices appear in the sound preferences dialog, it usually means that another application is using your soundcard(s). This problem only appears on Linux. To fix it, make sure no other applications are using your soundcard. The usual culprits are Firefox and the esound daemon. Closing Firefox normally will take care of the former, and running “killall esd” in a terminal will take care of the latter. If it's still not working, running “sudo fuser -v /dev/dsp*” and “sudo fuser -v /dev/snd/*” will show you the list of applications currently using your soundcards.
Mixxx 1.5 doesn't play nicely with Beryl/Compiz, as reported by several users. This is due to some funky OpenGL code inside QT3. Fortunately, Mixxx 1.6.0 no longer uses QT3 and reportedly works very well with Beryl/Compiz.
See the Vinyl Control page.
No, Mixxx does not write to or move any files in your library. It's safe to use Mixxx with your iTunes library - Mixxx it will not change anything in your library.
As of release 1.6.0, the official Mixxx binary releases attempt to support the following operating systems equally:
We also support the following platforms through binary releases on a best effort basis, not all beta releases will be built for these platforms and full releases often lag behind the release cycle by a month or so:
Many Linux distributions bundle their own copy of Mixxx rather than relying on our official releases, check with your distribution for more details.
Of course as an open source project, source is always available to build for whatever platform you work on, either a Linux distribution which doesn't provide Mixxx packages or something more exotic. Historically Mixxx has been known to compile on FreeBSD.
We are always happy to hear from people building Mixxx on other platforms, whether you are doing a one-time build for yourself or maintaining a Mixxx package for a distribution please get in touch.
As of release 1.6.0, Mixxx supports the following file formats: