MusE v1.0 alpha released (Linux/free)
MusE is a FREE multitrack virtual studio for Linux

Hot on the heels of prerelease of the latest stable incarnation 0.9pre2 comes a first preview of the coming MusE 1.0!

A disclaimer:
- It's not finished
- It's buggy
- It may not compile on your system
- It may cause (insert favourite error)
But it contains a lot of rework of the internals and externals of MusE, so if
you want to dive in and help us improve it please do so!

Some information adapted from the README
QT 4.2
GCC 4.x
JACK 0.102.20 (actually not in the README but should be there)

To build it:
- unpack the sources
- run 'cmake' in the base directory
- run 'make'
- run 'make install'

Some features adapted from the NEWS file:
- new "project" paradigma
- "auto fill" parts
- DSSI support
- JACK midi support
- graphical controller automation in arranger
- audio metronome
- support for VST plugins
- new midi routing code
- midi plugins
- parts and events are updated in realtime during recording
- new look

MusE is a MIDI/Audio sequencer with recording and editing capabilities written by Werner Schweer. MusE aims to be a complete multitrack virtual studio for Linux, it is published under the GNU General Public License. MusE has among other things support for:

* Midi sequencing
o Record/Playback/Import
o Input filter
* Audio sequencing
o Record/Playback several mono/stereo inputs/outputs.
o AudioGroups
o Perform audio effects like chorus/flanger in realtime!
* Jack - jack-audio-connection-kit
o Use the jack for midi/audio routing.
o Internal Audio Routing Interface
* ALSA - based on the Advanced Linux Sound Architecture

You can use several soundcards to access external midi devices and record/playback them with MusE.

MusE is a multitrack virtual studio for Linux that has support for sequencing of both midi and audio and has, among other things, support for LADSPA, Jack and ALSA.
Read more here.