alt Hacker NewsShow HN: I made a generative online drum machine with ClojureScript
After two years of development, I'm super excited to release Beat Maker! This is my take on what I hope is the best free, web-based drum machine.
My goal was to build something that was not only fun and easy to use for beginners but also powerful enough for serious producers. I did extensive research on existing drum machines, analyzed their UX, and tried to build something that adds something new.
It's a nearly 100% client-side app, written in ClojureScript, and is a PWA so you can install it to your home screen for an app-like experience.
Besides the standard grid editor, Beat Maker has some unique features that I think HN readers might find interesting:
- Procedural sample generation. One annoying thing about writing beats is searching through folders full of samples. I wanted to improve this and so I added the ability to generate new samples with a single click, giving you an infinite supply of unique drum samples. * Generative beat creation. If you're looking for inspiration, Beat Maker can generate entire patterns for you as a starting point. You can then edit and tweak the beat to your liking. Great for solving the "blank canvas" problem and giving you something good to start from. * Advanced export options. This is where it really shines for producers. You can export your work as: * A standard WAV loop * Individual stems (ZIP) * A MIDI file * A ZIP file of all your samples as WAVs * A SoundFont (.sf2) drum kit from your generated samples * An Impulse Tracker (.it) file for use in trackers like Renoise, OpenMPT or a Polyend * Pocket Operator/Volca sync. It can output a sync signal on the left audio channel to sync with these hardware devices for perfect timing. * Per-Note FX. You can add effects like volume slides, repeats, and start volume changes to individual notes for more complex drum phrases incorporating flam and roll.
As an old school tracker guy, I'm particularly excited about the Impulse Tracker export mode. I was surprised to discover how many DAWs (including hardware like Polyend) can import this format. Of course, you can also pull up Impulse Tracker on DOSBox, or the more modern re-implementation, Schismtracker for that retro experience.
By the way, the beat generator feature is not trained on any artists or anything like that. It's an algorithm I built from scratch myself.
The audio engine is built on a declarative audio graph (using `virtual-audio-graph`), inspired by React's virtual DOM, which makes managing the Web Audio API much cleaner. If you're building web based audio apps I highly recommend checking out this library.
I'd love for you to try it out and let me know what you think. Feedback (and the inevitable bug reports) most welcome! Thank you!
P.S. Also, here's a video summary: https://youtu.be/qVmEn9z3H24
Comments
This is great fun, congrats!
2 small requests that (I think) would help with the UX: consider moving (or duplicating) the play button - maybe directly in the middle below the editor, or on that panel itself. It took me a few confusing seconds to realise where it was. Also, could you consider making each fourth (or first) column a very slightly lighter grey? So if I want my kick on 1, 3, 10 and 11 it's really easy to see where to click without counting?
Really cool! How come you've chosen ClojureScript, and did you regret that choice in the 2 years you've been working on this?
To be clear, this is pure curiosity on my part as I love Clojure(Script) and am consistently missing it during my day job.
Love this!
One thing I'd find frustrating if using this when working on music: "When beat is playing, get new sample for drum plays as soon as it generates".
If "this sample is programmed to play in playing beat", then it'd be good to do a silent replace, or have the option to, so that you don't get a weird unquantized snare sound, for example. I'm finding it puts me off the generated sound more if I initially hear it in a context where it doesn't fit.
This takes me back to 2019 when me and my team won HackInOut, a hackathon held in Bangalore, India by building Rosaline, a generative drum machine, that took in lead melodies (guitar tracks, piano samples, etc) and generated a full fledged drum track.
Used GANs & a lot of weird hacky optimizations, can't even find the code for it anymore, but it was a great time :)
https://devfolio.co/projects/rosaline
This is all that's left of it
Thanks for building this. Really inspiring and great work.
ClojureScript is such an awesome secret weapon for building web apps. I started building a similar web audio looping app using borkdude's scittle version of ClojureScript. Only once the app had grown substantially, did I move on to proper ClojureScript. The cljs development experience is just awesome.
Very cool and quite fun. I love that you used Clojurescript. I played with it years ago and have been meaning to get back to it.
One piece of feedback; I'd love an option to toggle background color of everything nth note. Makes it easier to place on beat.
That background really captures the look of a dirty laptop display. I was actually taken aback at first, thinking that I must have somehow sneezed over my screen without realising!
It's not very mobile friendly but on desktop it's a pleasure! The ability to generate waveforms feels pretty novel, well done.
I really like it, and the FX option is a really fun addition on top of where most people get to. One ask I'd have is for FX to stay "on" and duplicate what was put down for each new cell until it's turned off again? It's a tiny thing.
Cool tool! I often play odd time signatures, e.g. I'm trying to program the drums for Rondo ala turk by Dave Brubeck (repeating 2-2-2-3 pattern). Can you tell me how I can do that?
Thanks for making this a web app, and not some app that only runs on half of the phones/tablets out there.
Dope!
One thing I notice is that the generated beats are very alike. Yeah it makes sense to play snare on the 2 and the 4, and to have kicks always fall on the downbeat, but you'd get more creative grooves if you allow for some more variation there.
It could even be a slider that allows you to stray away from the common patterns.
I had also build a similar (non polished) app using js: https://boombox-agw.pages.dev/
It also includes a bunch of greek rhythms; try tsifteteli!
Nice work! Nice that you also implemented an MPC-style swing. How do you generate samples? Are they also procedurally generated or are they chosen from a fixed set of samples? I suppose you're not planning to release any sources for this...
Really great, very responsive, fun, like the fact you can download your work in lots of different formats. Ace!
Very nice! ClojureScript rocks. Just curious, did you use any React for this, or is it vanilla HTML interop?
Is this able to be used with Strudel the code-based beat maker?
Pricing page could say what the features are
Seems like a cool, simple app
This is wonderful work. Thanks for sharing.
awesome tool! would be more usable to scroll horizontally as one page and ability to add verticals one at a time.
very nice, enjoy listening to the beats. also good to see something come out of Clojure land after a while
already using this to practice randomized beats on my drum pad. this is dope, thank you.
this is really great, I like it!
> "The audio engine is built on a declarative audio graph (using `virtual-audio-graph`), inspired by React's virtual DOM, which makes managing the Web Audio API much cleaner. If you're building web based audio apps I highly recommend checking out this library. "
when you have more and more interactions on the gui web audio api will become a problem, check out audioworklet.
I am developing https://glicol.org/ and it has a js port on https://glicol.js.org/ a typical usecase is drum machine with very high time accuracy