Mixxx is a DJ tool that allows for the playback and mixing of digital music (MP3, Ogg Vorbis, FLAC and Wave).
The basic requirements for Mixxx are a desktop computer or laptop with a reasonable amount of storage space on the hard drive for your music, at least 1 audio card for outputting the sound and a way of controlling the software either by mouse, keyboard or hardware DJ Controller.
Mixxx will run on the Linux, Mac OS X and Windows operating systems
Before you download and install Mixxx, consider what your hardware setup will be: your PC/Laptop, Audio Output and how you are planning to control the software.
While you can run Mixxx on a desktop PC, the examples here refer to using a laptop.
Just a laptop and the Mixx software. Relying on the onboard sound card to output your audio
A deck only DJ Controller allows you to control the Mixxx software. They can be a single or twin deck setup, but generally the twin deck controllers will have a jog wheel, volume faders, cross fader, EQ knobs, play & cue buttons. DJ controller's are a MIDI controller and while some manufacturers use a MIDI interface and cables many are now commonly using USB to connect to your laptop. You still need a separate audio card for listening through your headphones and the outputting the main mix.
For an example of a 2 Deck DJ Controller see the product site for the Hercules DJ control MP3
A DJ Controller with Audio means that your deck controller also has onboard sound. This allows you to plug your headphones into the controller, plug your outputs to the sound system and on some units add a CDJ, Turntable or Microphone.
For an example of a DJ Controller with Audio & Deck control see the product site for Hercules DJ Console Mk2
The ideal way for any DJ to mix live is to have 4 channels of Audio output. 2 for the main mix (to the room) and 2 for cueing and previewing the next track you are trying to mix in (to your headphones). This means either having multiple soundcards or a soundcard capable of outputting 4 channels of audio.
What is latency?
It is the time delay between the moment something is initiated and the moment the change becomes detectable.
So what does that have to do with Mixxx?
Your DJ setup must include a sound card whether internal (Onboard or PCI sound cards) or external (USB sound card or DJ Controller). The latency… If your set up includes a DJ Controller deck you may find that there is Midi latency to consider.