Spitfuzz — a velcro-y, sputter-y fuzz

This began as a response to u/markblack1977 on r/ZOIA’s question about making a sputtery fuzz. I sat down and began experimenting and by the time I felt confident with the answer, I had pretty much finished a basic patch for a type of sputtery fuzz sound. So, here we are. It could be improved, I think, but it might be a good patch for others to experiment with.

Below is a schematic for the patch, and an explanation of the schematic.

The signal path is mono, using the left input and output.

Spitfuzz schematic

Audio path (page1):

Audio input (L) –> fuzz (ugly)
Fuzz –> gate (with attack and release options selected)

Value modules renamed input gain and output gain are connected to the input gain and output gain of the fuzz and placed on the first/control page.

Audio to CV path (page2):

Audio input –> envelope follower

CV path (page2):

Envelope follower –> CV delay (set to 1.33 ms)

CV delay –> positive input of comparator1
Envelope follower –> negative input of comparator1

Comparator1 –> flip flop

This is a comparator functions as a slope detector. When the delayed envelope follower signal (i.e., what happened 1.33 ms before) is higher than the present envelope follower signal (i.e., when the envelope follower signal is decreasing/decaying), the comparator will go high. My thinking here was that I wanted the attack of the note to mostly break through intact and begin to sputter more as it decayed.

The flip flop is there simply because the “jumpiness” of the envelope follower was causing the slope detector to jump around too much. So the flip flop smooths it out just a little, tiny bit; changing the CV delay value would probably also address this, in retrospect.

Value module (renamed: Starve and placed on first/control page) –> positive input of comparator2
Envelope follower –> negative input of comparator2

Flip flop –> multiplier input1
Comparator2 –> multiplier input2

Multiplier –> gate threshold
Multiplier –> CV invert –> fuzz output gain

The second comparator determines how spitty the fuzz is. With lower starve settings, strong/hard playing will cause the envelope follower to rise above the value at the positive input of comparator2, causing the comparator to go low and break the AND gate it forms with comparator1 when they are joined at the multiplier. With higher settings, the slope detection will play a more prominent role in the process and produce a spittier fuzz, even with harder/louder playing.

When both comparators are high (the slope detector detects decay and starve comparator’s positive input is above the envelope follower), the output gain of the fuzz will be suppressed and the gate will be activated (this probably only needs the gate to be activated, but I started by suppressing the output gain of the fuzz without a gate module, and I left the connection because it did no real harm).

Value module (renamed: Threshold and placed on the first/control page) –> positive input of comparator3
Envelope follower –> negative input of comparator3

Comparator3 –> both inputs of the multiplier

The basic idea here is to set a minimal/noise gate level for the fuzz. When the envelope follower exceeds the threshold, the gate will open and the gain of the fuzz will increase.

Controls note placed:

Adjusting the attack and release of the gate module has an affect on the nature of the “sputter.” Right now, they are set to 1ms (attack) and 50ms (release), but you can play around with these to achieve different results.

As already mentioned, adjusting the CV delay value might yield smoother results.

Room for improvement:

While the overall effect is, I think, very similar to a sputtery/velco-y fuzz, I think it lacks the sort of compression that occurs as the sputters decay. This might be achieved by tweaking the gate’s envelope controls, or by adding compression of some sort that is triggered by the mechanism.

Tone/filtering, would, I think, add a lot, and could also be affected by the mechanism to give it a more cohesive feel.

No demo at the moment; if I update with a more complete patch, I will release one at that point.

  • State: Work In Progress
  • Platform:
  • Category: Effect
  • Revision: 1.0
  • License: Creative Commons Attribution Share Alike 4.0
  • Views: 818
  • Modified: 6 months ago
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