Aria Maestosa is a midi sequencer / editor. It lets you compose, edit and play midi files with a few clicks in a user-friendly interface offering score, keyboard, guitar, drum and controller views.
Giada is a free, minimal, hardcore audio tool for DJs, live performers and electronic musicians. How does it work? Just pick up your channel, fill it with samples or MIDI events and start the show by using this tiny piece of software as a loop machine, drum machine, sequencer, live sampler or yet as a plugin/effect host. Giada aims to be a compact and portable virtual device for Linux, Mac and Windows for production use and live sets.
Rosegarden is a music composition and editing environment based around a MIDI sequencer that features a rich understanding of music notation and includes basic support for digital audio. It’s an easy-to-learn, attractive Linux application that is ideal for composers, musicians, music students and small studios or home recording environments.
Frinika is a free, complete music workstation software for Linux, Windows, Mac OSX and other operating systems running Java. It features a sequencer, soft-synths, real-time effects and audio recording.
Qtractor is an Audio/MIDI multi-track sequencer application written in C++ with the Qt framework. Target platform is Linux, where the Jack Audio Connection Kit (JACK) for audio, and the Advanced Linux Sound Architecture (ALSA) for MIDI, are the main infrastructures to evolve as a fairly-featured Linux desktop audio workstation GUI, specially dedicated to the personal home-studio.