Acid Bass & 303 SoundsLesson 1 of 5
The 303 Blueprint
THE CONCEPT
The Roland TB-303 Bass Line was designed to simulate a bass guitar. It failed at that — but accidentally created one of electronic music's most iconic sounds. Its secret: a sawtooth or square wave through a resonant 18dB/octave low-pass filter, with a dedicated envelope controlling the filter cutoff. The envelope decay and the filter cutoff interact to create the characteristic 'squelch'.
TRY IT
Set up a sawtooth wave and route it through a low-pass filter. Set the resonance high (around 70–80%) and the cutoff low. Now trigger a note and sweep the cutoff up — hear that squelch. The acid sound lives in the interaction between resonance, cutoff, and the speed of that sweep.
FILTER
2.0kHz · Q 2.1FILTERED OUTPUT
2.0kHzCUTOFF
Q 2.1RESONANCE
OCT 4
NO MIDI
ASDF…=WHITE · WETYUO=BLACKA
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THINGS TO NOTICE
✦High resonance is essential — it creates the nasal, vocal quality.
✦The cutoff sweep speed controls how 'open' or 'closed' the sound feels.
✦Accent notes hit harder and open the filter more — creates rhythmic variation.
✦Portamento (pitch slide between notes) is a defining 303 characteristic.