This album is designed as a song-writing tool. If you listen to it expecting complete songs, I'm afraid you're missing the point.
These tracks have chord progressions accompanied by a simple metronome. The goal isn't that you simply listen to the tracks, but open up your mouth and sing a new song. Each song is under 10 minutes long, with a key/scale reminder for an introduction, as well as three different three minute subsongs, each with a distinct chord progression and tempo.
The progression names come from autochords.com
-- While there are other progressions there, we restricted ourselves to chords specifically in the target key, as well as progressions that didn't change roman numerals if the key was changed from major to minor. If you're looking for chords to spice up your draft, though, that place can help.
The idea is that it may help you perform a "3in10", three songs written in 10 minutes. While this is quite doable, it is sometimes hard to do so while adding sufficient diversity to each of the songs. These tracks help with that. For the a-capella improvisers, these tracks also help mix up the key being used.
The contents of the tracks were selected randomly. The keys chosen from were exclusively popular keys. We have made sure that the MIDI instruments for each track were unique, but also tried to make sure that they were listenable for the goal at hand. To assist with properly hearing the scale, the scale is also performed with a trumpet.
There are twenty tracks here specifically to allow folks to roll a 1d20 to select the track to use to perform a 3in10.