808 Hi-Hat
Tune the noise by adjusting the mixer levels to taste. I added some of the original noise back in to make it more metallic, but you can ommit this.
Tune the VCF frequency to somewhere between 8,000 and 12,000 Hz, A8 to E9 is good. Experiment with different filter modes: BP2, BP4, HP4, LP4, LP2.
MIDI pitch CV controls decay time. Low pitch CV plays closed hats. High pitch CV plays open hats.
The 808 uses a complex array of 6 square wave oscillators tuned to create an inharmonic hum. There frequencies are as follows:
1: 800 Hz = G5 +35¢, Range = 359.4 to 1149.9 Hz = F4 +50¢ to D6 -37¢
2: 540 Hz = C#5 -45¢, Range = 254.3 to 627.2 Hz = C4 -49¢ to D#5 +14¢
3: 522.7 Hz = C5 -2¢
4: 369.6 Hz = F#4 -2¢
5: 304.4 Hz = D#4 -38¢
6: 205.3 Hz = G#3 -20¢
Oscillators 1, and 2 are tuneable via internal trimpots. They are factory tuned to 800 and 540 Hz. Oscillators 1 & 2 are also used for the cowbell.
Oscillators 3 to 6 are not tuneable, and resistor variance could cause the measured frequencies of any particular real 808/606 to be out by 20%. If you’re trying to get the 808 cymbal/hihat sound, don’t worry about nailing the exact frequencies. What’s important is that the summed frequencies add up to an inharmonic hum. Avoid even multiples.
Cascadia doesn’t have 6 square wave oscillators, however you can use one of the cymbal alt noise sources. There are 3 cymbal noises. 1: a high pitched hum. 2: a chopping/whirring noise 3: a lower metallic hum. Try them all. 3 is the best, but 1 is good too.
The 808 has a bandpass and a high-pass filter running in series. Here, I have them in parallel running into a mixer, more how the 808’s cymbal is set up.
1: MIDI pitch to ENV-B shape. Turn the shape slider up.
2: Patch ENV-B to VCA-B in, then VCA-B VCA out to VCA-A CV in.
3: MIDI velocity to VCA-B CV in.
4: Patch the noise to the filter. Switch noise to alt, and select one of the cymbal noise sources. To select different noise flavours, hold down the red manual gate button and click the buttons in the MIDI/CV section.
5: Set the filter to bandpass 2 or 4 with a frequency of 10,000 Hz.
6: Raise Q a little. Raising filter resonance accentuates the high frequencies. Don’t raise it too high, or it’ll screech. Find a nice balance.
7: Patch VCF out, and VCF HP4 out to mixer in 1 and 2. Set the mixer levels to taste.
8: Patch the mixer to VCA-A in.
Further Reading
A short post I made while researching how to recreate 808/606 cymbal and hi-hat sounds in modular.
The TR-808 Cymbal: a Physically-Informed, Circuit-Bendable, Digital Model
A paper analyzing TR-808's cymbal voice circuit, aiming to create a digital model of it. Lots of information in here.
Pg. 6 has a brief descriptions of the cowbell, cymbal, open and closed hats.
Pg. 7 is a block diagram.
Pg. 14 has a chart showing amplitude, frequency, and decay times of most 808 sounds.
The Doepfer A-117 Digital Noise / Random Clock / 808 Sound Source
The A-117 has 2 and 6 oscillator outs for recreating 808/606 cowbell and cymbal sound sources. Check out the PDF manual on this page for more info and a few pathing ideas.
See the manual linked on this page. While not a clone of the 808 hat, there’s a lot of good information here.
Designing a TR-606 style hi-hat from scratch (Youtube)
Moritz Klein, the designer of the Erica Synths EDU DIY Hi-hat describes how the module works.
Analysing Metallic Percussion (SOS)
Explores the challenges of synthesizing metallic percussion instruments like cymbals, hi-hats, tam-tams, and gongs.
Synthesizing Realistic Cymbals (SOS)
Synthesizing cymbals using FM synthesis and the Nord Modular.
Practical Cymbal Synthesis (SOS)
How to synthesize the cymbals from the 808 and 909.
This article is mostly about bells, but the epilogue at the bottom has a brief description of the 808 hi-hats.