VCVRackTutorial: Quad Delay Drum Destroyer

Patch file:

Bonus patch file (melodic)

This is a demonstration of the utility of parallel repetition of the same basic signal chain. I like to think that it mirrors the musical idea of harmonic relatedness and modulation.  Instead of affecting pitch, this patch affects time, in a rhythmically interesting way.

This patch uses controllers (buttons), and modulation sources to crossfade between a dry signal — in this case a drum machine with some built in random variations — with the same signal delayed and filtered.

TOP ROW: Drum Machine

This uses a VCV Pulse Matrix to drive an instance of a Vult Trummor 2 (for kick and snare and a Hora Treasure Hihat. Each sound uses 2 rows of the Pulse Matrix — one set to play forward, and one set to play in random order.  The two rows are then combined using a NYSTHI Logic Module’s OR function. The random triggers are fed through Audible Instruments Bernoulli Gates to thin out the hits that get dropped into the pattern. You can turn up the balance knob on the Bernoulli Gates to get more randomness in your pattern.  In the saved patch, this is tuned to my liking.

DELAY ROWS: Wonky Modulation

These are all essentially the same. Going from right to left there’s a Submarine XF-201 Crossfader, that takes the signal from the row above — in the first case, the output of the drum machine mixer, and a delayed, effected signal.

There’s an AS DelayPlus Delay followed by an XFX F-35 Filter which is the ‘wet’ side of the crossfader. The delay times are set with voltages from the AS BPM Delay/HZ Calc module to musically useful values.

Crossfader Control

This is a bit tricky, and required some fiddling to get mostly right.  There’s an RJ Modules Button you can hit which will flip between the dry and effected signals.  The manual control is combined (via an NYSTHI Logic module) with a clocked random gate from a Matthew Friedrichs March Hare module, fed through another Bernoulli Gate to thin out the gates somewhat.  The March Hare’s Synced Random source is cool because the random gate signal is triggered on beat based on the clock input.

The output of the Logic ‘OR’ gate triggers an AS ADSR Envelope, which then controls the crossfader module.   The beauty of this arrangement (with the clocked random gate) is that A) the Bernoulli Gate gives you control over how much random triggering takes place and B) the envelope smooths out the crossfade, much like slew limiter (or a Befaco Rampage with rise/fall controls).  In particular the release phase gives a nice effect where it mixes back from the delayed signal to the dry signal.

To work properly — i.e. go from dry to wet 100% when the envelope is triggered — you need to right click/ctrl click on the NYSTHI Logic module and select 0-10V operation. It defaults to 0-5V signals, which will only turn the crossfader to 50%.


Push the buttons on the left side of the patch in order to manually bring the delayed/filtered signal in.

You can add some automatic triggering of the crossfade envelope by tweaking the balance on the Bernoulli Gates. Fully clockwise (i.e. no gates pass through, complete manual control) to any amount counterclockwise.   If you go close to full clockwise, you’ll get more delayed signal than dry most of the time, and the patch begins to sound like a demented robot version of Max Roach, continuously varying the pattern.

And since the delay/filter rows are daisy chained, you can have one or more of the wet signals coming through, and each row affects the output of the row above it.  I think it gives a really really liquid-sounding mixing of ghost hits and repeats.  It takes on a life of it’s own and only rarely sounds awkward or out of time.


I can think of several things you can do with the patch to get even wonkier.

  • Use different left and right delay times on the delays. I gave up on this because it gets really hectic.
  • Use another crossfader to mix the last row back into the first row’s delay along with the dry signal from the drum machine.  This can go non-linear and overloaded with only a bit of feedback, so I’d use it sparingly, and put a NYSTHI 4DCB in front of the wet signal, because this kind of feedback through a long signal chain can destroy your signal with DC offset.
  • Use effects besides filters. Filters are the most natural thing to use.  One thing that will sound jarring is crossfading between the dry signal and an effect that adds stereo separation (like a stereo Chorus or Flanger).
  • Scale the envelope output into the crossfader, so that you don’t go all the way to 100% wet signal.
  • Get rid of the drum machine, use VCV Bridge for audio input and output, and load VCVRack + this patch as a send effect in a DAW.

Have fun, and let me know if you have any questions!