Goa trance's signature squelchy sound is a sawtooth wave through a resonant band-pass or high-pass filter

The squelchy sound that originated with Goa trance and became even more prevalent in psytrance is synthesized by running a sawtooth-wave oscillator through a resonant band-pass or high-pass filter with modulated cutoff. As the filter sweeps, the resonance emphasizes harmonics at the cutoff frequency, creating the characteristic squelch or yowl. This sound bridges the TB-303 acid tradition (resonant filter on sawtooth/square) and Goa’s psychedelic aesthetic. It became a key genre marker distinguishing Goa from straight trance.

Examples

Roland TB-303 used for acid-style squelch; Roland SH-101 and Juno-60/106 used for more melodic but filter-modulated lines. Novation Bass-Station as affordable analog source.

Assessment

Describe the synthesis chain that produces the Goa trance squelchy sound. What two oscillator/filter parameters would you modulate to make it more or less pronounced?