A techno rumble kick is the kick's own reverb tail filtered to sub-bass and re-shaped by an envelope

The classic techno rumble kick uses two copies of the same kick sequenced identically. Copy A goes to the mixer with light EQ (the audible punch). Copy B is routed through a short, bass-heavy reverb, then a VCF that filters out the top end so only the bass of the reverb remains, then EQ, into its own mixer channel. An ADSR — triggered by the drum sequencer on every kick — modulates the VCF cutoff so the filter opens and shuts tightly on each hit, cutting the reverb into a controlled sub rumble. The ADSR uses a small attack so the sub arrives slightly after the kick transient, reinforcing the low end without smearing the initial punch. Both channels are then mixed.

Examples

In VCV Rack: a BD-9 kick feeds EQMASTER → mixer (punch), and a second identical BD-9 output feeds XFX Reverb → VCF (cutoff modulated by an ADSR the sequencer triggers) → EQMASTER → mixer (rumble). Press Q to start; turn a channel down to hear each part solo.

Assessment

Describe the signal path of the rumble layer from kick output to mixer. What is the ADSR’s role on the filter, and why is its attack set slightly after the kick transient?