The Misfit Audio Transistor 808 Hats module is a synthesized recreation of the legendary closed and open 808 hi-hats with controls for pitch, decay, color, impact, partial balance, body, and choke.
Cymbal Synthesis Primer
The following section explains how cymbals are synthesized in the classic Roland TR- and CR- drums machines. This will help you to better understand the Transistor 808 Cymbal module controls.
If you've ever tried to create a cymbal sound on an analog synthesizer, you might have used some sort of filtered white noise and quickly concluded that this doesn't work well. Though cymbals don't generally have an identifiable underlying root pitch, they're a unique amalgam of pure noise and somewhat random pitched content, generally described as a "metallic" tone. This randomly pitched metallic characteristic is why white noise fails miserably when attempting to synthesize realistic sounding cymbals.
We don't know how they arrived at this, but the key to synthesizing Roland-style cymbals lies in using four or six pure square waves, tuned to random intervals (the frequency span is generally from around 200-800 Hz, though it's not that critical). On its own, this creates a fat, huge atonal mess, but patch this "noise hash" through a steep highpass filter, and you're left with a surprisingly realistic cymbal tone. (Incidentally, the TR-808 used a "hex inverter" logic chip that's simple to mildly "misuse" in order to create six simple square-wave oscillators.)
The above description above is a simplified a bit - an actual TR-808 then splits the cymbal oscillator "hash" in order to replicate the higher pitched initial segment of the sound and the lower pitched "body" of the sound. These use separate amplitude envelopes and are filtered a little differently, then mixed together. This is accurately replicated in the Transistor 808 Hats module. The TR-808 cymbal sound (i.e. not the high-hats) uses the same six-square wave oscillator source with its own associated filtering and enveloping.
Inputs, Outputs, and Controls
Closed Trig In jack- A 5V trigger received at this jack triggers the closed hi-hat sound at "normal," unaccented level. The LED lights when the jack is triggered.
Open Trig In jack- A 5V trigger received at this jack triggers the open hi-hat sound at "normal," unaccented level. The LED lights when the jack is triggered.
Closed Acc (Accent) In jack- A 5V trigger received at this jack triggers the closed hi-hat sound at the accented level set by the Accent Level knob. The LED lights when the jack is triggered.
Open Acc (Accent) In jack- A 5V trigger received at this jack triggers the open hi-hat sound at the accented level set by the Accent Level knob. The LED lights when the jack is triggered.
Choke- When Choke is on, triggering the closed hat cuts off decay of open hat sounds.
Pitch- Adjusts the pitch of all six square wave oscillators simultaneously.
Open Hat Decay- Sets the decay rate of the open hat sound.
Accent Level- Sets volume for closed and open hat sound when the accent inputs are used.
Color- This crossfades between the lower three and upper three oscillator square waves. Lower positions emphasize lower harmonics; higher positions emphasize higher harmonicss. Center position mixes all six waves evenly.
Impact- Mixes in a click sound to emulate stick impact.
Partial Balance- Crossfades between high and low filtered and tones. The high partial tone has a faster decay than the low tone.
Body- Controls the frequency of the master highpass filter. Lower settings create more body; higher settings will be thinner.
Out jack- Outputs the closed and open hi-hat sounds.