Reaper - Reaper is a focused digital audio workstation (DAW) developed by Cockos. In the creation of the software, the digital audio technology company intended to make audio editing accessible to the masses.
Sibelius - Sibelius is a virtual score creation tool which allows composers to easily create new piano scores, developed by Avid.
Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.
music21 - Music21 is a Python-based toolkit for computer-aided musicology.
Ardour - Record, edit, and mix on Linux, Mac OS X, and Windows.
Harmony Assistant - Harmony Assistant is an unbeatable software for computer-assisted music composition and editing.