This sound originated from Chicago in the mid-'80's. It's phased and gated quarter note percussion patterns generated by the Roland TR 808 and 909 drum machines marked a milestone advancement in synthdriven dance music. The acid house sound was an overnight revolution and remains the cornerstone of the American underground scene. Attrlbutes: the Roland 303 bass machine signature sound. 118 to 130 BPM. Examples: Tyree, Armando and anything on DJ International or Trax labels.