Cantabile is described as 'music workstation for live performing musicians. Build your ideal rig - one that leaves you free to focus on giving your best performance' and is a music production app in the audio & music category. There are more than 25 alternatives to Cantabile for a variety of platforms, including Windows, Mac, iPad, Linux and iPhone. The best alternative is Ableton Live. It's not free, so if you're looking for a free alternative, you could try GarageBand or Carla. Other great apps like Cantabile are Bespoke Synth, VSTHost, AudioMulch and NanoHost.
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.
Carla is an audio plugin host, with support for many audio drivers and plugin formats. It has some nice features like automation of parameters via MIDI CC (and send output back as MIDI too) and full OSC control.
NanoHost is not a synthesizer. It is a free, minimalist host application for Windows that can load VST-synths. Furthermore, it can act as a wrapper which converts VST-synthesizers into standalone applications.