Buzztrax is described as ', previously called Buzztard, is a modular, free, open source music composer conceptually based on Buzz ' and is an app in the Audio & Music category. There are six alternatives to Buzztrax for a variety of platforms, including Windows, Linux, Mac, Windows Mobile and iPhone. The best alternative is SunVox, which is free. Other great apps like Buzztrax are Radium (Paid, Open Source), Buzz (Free), Psycle (Free, Open Source) and Buzé (Free, Open Source).
SunVox is a small, fast and powerful modular synthesizer with pattern based sequencer (tracker). It is a tool for those people who like to compose music wherever they are, whenever they wish. On any device.
Buzz is the first ever "easy to use" free modular software based synthesizer. What this means is that the entire system is based on objects, which may be routed in a modular fashion, giving you the freedom to be as creative as you want.