GuitarOperator — a pitch-tracked FM synth

GuitarOperator (or BassOperator or flute or whatever you want to throw at it that produces pitch) is a 3 operator FM synth. It can sound very mild or very, very gnarly.

Each of the oscillators (operators) can act as carrier or modulator (or both), allowing for a wide variety of algorithms from 3 operators, each can also be fed back into itself (great for thickening up a sound or creating distortion).

There is also a ring mod mode and a sustain/drone mode that turns it into a pretty interesting noisemaker (to my ears).

Weird, wild sounds.

The signal path is mono throughout, from the left input to the left output.

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Left, latching — enables ring mod mode (a yellow light will grow brighter on the front page)

In ring mod mode, operator 3 is used to modulate operators 1, 2 (and it can also modulate itself). You can disable pitch tracking on operator 3 (button next to its pitch control); with negative pitch values, it can act as a tremolo; with positive pitch values, more like a classic ring mod; with pitch-tracking enabled, you can get an interesting pitch-tracking tremolo, where the rate increases as you play higher notes

Middle, latching — enables drone mode (can be loud) (a white light will grow brighter on the front page… also you will hear this, unless all of the carriers are silenced)

This can also act as an “infinite” sustain mode, which can be cool for actively playing with; or, it can be a neat tabletop noisemaker

Right, latching — enables diffuser (a red light will grow brighter on the front page)

Front page:

Each operator is arranged in a matrix mixer, with each colored row corresponding to one operator.

You can set the pitch for each operator.

You can determine the amount of its signal sent to the other operators (e.g., Osc 1 to Osc 2) and itself (feedback): each connection has two controls, a value for setting the level, and a pushbutton for turning that connection off and on, allowing you to quickly change between sounds.

At the bottom, you can turn modulation off; rather than using the modulators (second page), this allows you to set the set the index to a maximum amount determined by the level.

There is also a pushbutton that determines whether that operator acts as a carrier (is heard); there is some gain compensation employed, as more carriers are added.

Along the right side, there are some additional, global controls:

Diffuser gain — sets the gain of the diffuser, adding a reverberant space to the mix (the patch excels at gnarly, empty warehouse sounds)

Osc. glide — controls a slew limiter, allowing for notes to glide between one another

LP frequency — used as a tone control; this is a non-resonant multi-filter

Mix — wet/dry mix (you could use this as a volume control for the drone mode)

On page 2, you can select different modulation controls:

At the top of the page are controls for the modulators:

From the five channel switch:
1. Envelope follower (there is a slew limiter at the top of the page to control the rise/fall)
2. ADSR (the ADSR is on the page so you can make adjustments)
3. Exponential ADSR (exponential version of ADSR on page, so uses the same controls)
4. Triangle wave LFO (rate is on the page
5. Random module (rate set by LFO rate)

On the bottom of the page are controls for the carrier:

From the three channel switch:
1. Envelope follower (there is a slew limiter with only its rise exposed; you want to leave the fall at 0ms)
2. ADSR (this ADSR is also on the page, just above the switch)
3. Exponential ADSR

In short: FM is complex; putting it in a guitar patch is hard; watch the video; I think the drone mode is killer.

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  • Category: Effect Synthesizer
  • Revision: 1.0
  • License: Creative Commons Attribution Share Alike 4.0
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  • Modified: 3 months ago
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