The chip singers are:

Main: Cidertalk '84 (Macintalk, AMIGA's Narrator.device)
Harm: Rotten.ST (ATARI ST's stspeech.tos)
Bass: S.A.M. (Software Automatic Mouth)

Lyrics:

Welcome to Bot Buh!
You must like music, huh?
We make great chiptunes!
And we shit prunes!
We have all the formats for you!
You can even bring your own crew!
You're gonna have a good ol' time
with Puke7 and his battle of the bits!