Lately i started working on the sound-modules themselves rather than the 'computer'-part controlling the entire thing. I started with the bass drum module because it is one of the most inportant modules. When working with software drum synth or synthesizers in general i always found it difficult to create a bass-drum sound which is punchy and pumping at the same time. Another important aspect for this project is that the electronic should be as simple as possible and the electronics should be buildable with cheap and easy to find parts.
The core of bass drum modules is a 40106 hex inverted-based oscillator. Normally this oscillator is used to create rectangle-wave signals. However one can also get something like a triangle-wave signal when using the voltage at the input rather than the output of the hex inverter. The frequency of this oscillator is controlled with a decay envelope and a pot.
The output the goes into a voltage controller amplifier. The volumes is controlled with a simple envelope which consists of a decay envelope signal and a square pulse signal summed up. The idea is to have a punchy attack, done with the decay-envelope and some kind of a compression effect, done with the square pulse.
The schematic of this layout is shown below. At the moment the module is built and being tested, sound clips and/or vids following soon, stay tuned!!