Complex sentence: A particularly influential bass synthesizer was the Roland TB-303 following Firstman SQ-01, featuring a built-in sequencer and released in late 1981, and which would later become synonymous with acid house music.
Split into simpler sentences: A particularly influential bass synthesizer was the Roland TB-303 following Firstman SQ-01. Released in late 1981, it featured a built-in sequencer and later became strongly associated with acid house music.