The Roland TB-303
bass synthesizer provided the electronic squelch sounds often heard in acid house tracks.
Acid house's minimalist production aesthetic combined house music's ubiquitous programmed four-on-the-floor 4/4 beat with the electronic squelch sound produced by the Roland TB-303 electronic synthesizer-sequencer by constantly modulating its frequency and resonance controls to create movement in otherwise simple bass patterns. Other elements, such as synthetic strings and stabs, were usually minimal. Sometimes tracks were instrumentals such as Phuture's "Acid Tracks", or contained full vocal performances such as Pierre's Pfantasy Club's "Dream Girl", while others were essentially instrumentals complemented by the odd spoken word 'drop-in', such as Phuture's "Slam".
English acid house and rave fans used the yellow smiley face symbol simply as an emblem of the music and scene, a "vapid, anonymous smile" that portrayed the "simplest and gentlest of the Eighties’ youth manifestations" that was non-aggressive, "except in terms of decibels" at the high-volume DJ parties. Some acid house fans used a smiley face with a blood streak on it, which Watchmen comics creator Alan Moore asserts was based on Dave Gibbons' artwork for the series. The origin of this usage was the bloodied smiley from Watchmen on the label of "Beat Dis" by Bomb the Bass.