I recently made a small macOS menu bar app called SoothingKeys. It adds soft typing sounds to key down and key up events, but the main reason I built it was to explore how far I could push small variations in very short UI sounds.

The basic problem was that simply replaying the same sample for every keystroke gets annoying very quickly. Even if the source sample is nice, repeated short transients start to feel mechanical. So the app slightly varies pitch, filtering, sample start position, stereo position, and timing so each hit feels a little different without becoming obviously random.

Key down and key up are treated as separate sound events. The key-down sound is designed as the heavier impact, while the key-up sound is lighter, shorter, and thinner, more like a switch returning. That separation ended up being important for making the typing feel less like repeated clicks and more like a physical action.

I also tried to account for the way a keyboard housing colors the sound. The presets can control brightness, pitch instability, stereo spread, filter variation, and notch-like filtering to simulate some of the resonance and coloration you would get from a case, plate, or internal cavity.

There is also a browser-based preset generator. It lets you combine a sample layer, an oscillator click, and filtered noise, then export a preset ZIP for the app. The idea is not full physical modeling, but a lightweight sound design tool for making responsive typing feedback.

I would love feedback from sound designers: does the approach make sense? Are there better ways to avoid repetition in very short UI sounds? Would you approach the key-down/key-up split differently?

App, if anyone is curious:

[https://slndesignstudio.com/soothingkeys/](https://slndesignstudio.com/soothingkeys/)

I have also worked on [SND.dev](http://SND.dev) before, an open-source sound file project for UI sounds. If you are interested in UI sound design, you may also find this useful:

[https://snd.dev/](https://snd.dev/)

Procedural typing sound generator for macOS