Qtractor is described as 'Audio/MIDI multi-track sequencer application written in C++ with the Qt framework' and is an app in the Audio & Music category. There are more than 50 alternatives to Qtractor for a variety of platforms, including Windows, Mac, Linux, iPhone and Online / Web-based. The best alternative is LMMS, which is both free and Open Source. Other great apps like Qtractor are FL Studio (Paid), Reaper (Paid), Ardour (Freemium, Open Source) and Ableton Live (Paid).
FL Studio (originally known as FruityLoops) is a full-featured Digital Audio Workstation (DAW) offering a complete range of professional tools for everything from audio editing and beat creation to advanced arrangement, composition, mixing and mastering.
Ardour is a hard disk recorder and digital audio workstation application. It runs on GNU/Linux, Mac OS X, and Windows. Ardour's intention is to provide digital audio workstation software suitable for professional use.
Welcome to the school of rock. A Mac-sized practice space. Your own recording studio. If you want to learn to play an instrument, write music, or record a song, GarageBand can help — whether you’re a rookie or a rock star.
Make music online with a powerful set of tools ranging from synthesizers and samplers to mixers, delays, reverb and much more. AudioTool is an advanced, collaborative DAW (Digital Audio Workstation) built for the browser.