FOSSPicks

DJ software

Mixxx

Mixxx started life more than 20 years ago as an application to help DJs organize and play their playlists, and it has since evolved into an incredible, fully fledged, live performance user interface for budding and professional DJs, podcasters, and radio hosts. It's a worthy competitor to the proprietary (and Linux incompatible) Native Instruments Traktor Pro, with both applications using the same user-interface paradigm. That paradigm involves two or more decks split horizontally across the main window with a bank of virtual faders and controllers in between them. The number of controls you see here depends on the number of decks you add.

A deck is akin to an old vinyl record deck or turntable, now popular again in their own right. Nightclub DJs would typically arrange two decks side-by-side with a mixer in the middle, so tracks could be switched between them with no delay. It's this configuration that Mixxx emulates, albeit for the 21st century. Instead of records, the virtual decks load one or more audio files for playback, with the virtual faders used to mix between opposite decks. Audio files can be loaded individually, dragged and dropped, or queued as a playlist. This configuration allows you to seamlessly blend between various audio tracks, whether they are breakbeats or advertising jingles, and either record the output as a single audio file or use it as the source of a live mix or broadcast.

To make transitions as seamless as possible, Mixxx is able to analyze the audio files to detect their tempo, frequency range, and even key. All of this is shown on the waveform, with the tempo highlighted as vertical bars, frequency range as color, and key as an annotation. Pitch controls can then change either the key, playback speed, or both, making it incredibly easy to match different audio files for a more integrated mix. If you still yearn to exercise those old DJ skills, you can drag your mouse across the waveforms to virtually scratch the needle across the record, producing beautifully authentic sounds. This can be taken even further by using a real turntable spinning a timecode vinyl record, which can be tracked by Mixxx inputs to accurately map your scratching to changes in playback speed. Everything can also be automated, either by the many keyboard shortcuts or via MIDI automation, where every knob and slider can be assigned a MIDI control value for external control. These can be scripted for even more control.

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