Trax is basically a sampler built into the popular game Habbo Hotel. Players can select from numerous samples of various length, place them on a timeline, and create songs this way. Unfortunately, the feature was removed from the game when it was upgraded from Shockwave to Flash. Since it's such a fun little feature, I decided to make a simple clone.
I used Winforms for the interface and XNA for the sound playback. I choose to use XNA instead of .NET based sound playback, because it can use DirectSound, which is must faster. Timing is very importantant for a sampler.
My clone allows for creating, playing, saving and loading of Trax. The files are saved as .xml files so they can easily be read by humans and exchanged where needed. Due to copyright issues, I have not yet released a version of the Trax machine with sounds. You can download the source here, but the samples themselves are not included.