u/Renatachiptune

I've been building a chiptune app called Renata for about nine months of evenings. The tune in the video is one it wrote, on the YM2149 profile, at 150 BPM in F# minor — 56 bars, seven tracks. You can watch me set the eight dials in the video and then paste a seed back in to get the same song a second time.

The Atari bits: one of the nine themes is the GEM desktop in the real ST system font. While it composes you get raster bars, a starfield and a rotating vector cube in the YM's own colours. It exports .ym, .ay and VGM, and it browses the SNDH archive from inside the app.

The .ym is a proper YM5 register log — 4,477 frames, 70 KB. The MP3 of the exact same tune is 3.5 MB, because the .ym stores the chip writes rather than the sound.

On origin, plainly: there is no model of any kind. It is rule-based — music theory plus statistical tables — and it runs offline on your own machine.

It goes to Kickstarter on 8 September 2026 if you want to follow along: https://www.kickstarter.com/projects/markwrightretro/renata-make-your-own-copyright-free-chiptune-music

I've spent about nine months of evenings building a chiptune program, and it's written a hundred tracks. Seventy-five of them are free for anyone to use, and I'd rather they ended up in someone's game than sat on my drive.

The licence first, because it's the only part that decides whether this is any use to you: use them in anything, including commercial releases. Modify them however you like. Credit appreciated, not required. And they can't be registered with a content-ID system or a performing-rights society — so nobody can claim them on your trailer, your devlog or a stream of your game, and that includes me. The one restriction is you can't resell them as music.

https://renatachiptune.itch.io/the-hundred

What they sound like: YM2149 — the Atari ST chip — so three voices and a noise channel, bright and hard rather than the C64's fatter sound. About four and a half hours across the 75. You get MP3s, and the raw .ym chip files if you'd rather run them through an emulator. The track list gives key, BPM, mood and length for each one, so you're not auditioning all 75 to find something that fits.

Where they came from, plainly: the program composed them. No generative AI — there's no neural network in it and nothing trained to imitate a composer. It's rule-based: statistical tables fitted on public archives of real chiptunes, plus music theory. Closer to how a roguelike lays out a level than to Suno.

Not selling anything and there's nothing to sign up to. If it's useful, take it — I'll be in the thread if you've got licence questions.

I've been building a chiptune player and transcriber for Windows, on and off for a while.

It plays chip formats and turns them into multi-track MIDI you can open in a DAW.

The clip it's playing Trantor, by David Whittaker — the Atari ST version, a .ym register dump — and then converting it. The Convert menu does MIDI, WAV, MP3 and FLAC, and there's a re-voice option that renders a tune onto a different chip.

It's called Renata and it isn't released, so this is a "look what it does" rather than a "go and get it". Mostly I wanted to show it to people who'd actually know whether the transcription is any good.

Happy to answer anything about it.

I've been writing a chiptune player/converter for Windows, and part of it exports YM2149 tunes as `.ym`. Everything I've produced has only ever been heard through emulation — mine and other people's — and I have no ST to check against. That's an uncomfortable place to be, so I'm asking the people who'd actually know.

Would anyone here with real hardware be willing to run a couple of files and tell me what they sound like? Happy to send whatever's convenient — a handful of short ones, or the lot.

Here's exactly what you'd be getting, so you can judge whether your setup will even take it:

`YM5!LeOnArD!` header, **uncompressed** — no LHA wrapper. Most `.ym` in the wild are packed, so this may be the first thing that trips a player up.

Interleaved data (attribute bit 0 set), so it's stored register-plane by register-plane rather than frame by frame. Fine if you load the whole file, awkward if your replayer wants to stream frames off disk.

2 MHz master clock, 50 Hz frame rate, no digidrums, no loop frame.

16 bytes per frame → 800 bytes/sec → about 48 KB per minute. A three-minute tune is ~145 KB, which I'm aware is a real chunk of a 512K STFM. The short ones are ~70 KB.

What I actually want to know, in rough order of how much it's bothering me:

1. Does the mix balance survive? Three voices at volume 15 sum past full scale in my emulated mix, so I trim every fixed-volume write down by two steps to stay clear of clipping. That trim is tuned against an emulator's summing, and the real chip's 4-bit output isn't linear and doesn't sum the same way. I'd half expect the balance to come out wrong on hardware, and I'd rather know.

2. Do the envelopes behave? I use `R13 = 0xFF` to mean "don't retrigger", and I do a hard restart — two blank frames before every gated note — to stop repeated notes at the same pitch slurring together. If that reads as clicks rather than articulation on real hardware, that's a bug I can't hear from here.

3. Is the vibrato audible as vibrato? It's done at period level rather than in semitones — about ±13 cents at 5.5 Hz — so it's the tone period stepping between adjacent values. On an emulator it sounds like a played note. On a real chip I have no idea whether it's vibrato or just noise in the low bits.

4. Do the drums land? Percussion is a noise transient followed by a short downward tone sweep, and it steals a voice from the chords while it plays.

5. Does it load at all, given the uncompressed + interleaved combination above.

"It sounds fine" is a completely useful answer, by the way — I'm not fishing for a critique, I just want to know whether what I'm hearing is what the chip does.

Two disclosures, up front:>

The app is mine and it isn't released yet, so this is me asking a favour rather than

pointing at a product. Picture is it playing one of the files, in a theme I built for the

ST palette specifically.

And the tunes themselves are composed by the program, not by me. There's a seeded composer behind them that writes the register stream directly — same seed, same tune, every time — and it produced a hundred of these in a batch. I'm not going to dress that up as hand-written; if algorithmically composed music isn't your thing, entirely fair, and the hardware question stands regardless of what's in the file.

Thanks either way — and if the answer is "your exports are subtly wrong and here's why", that's the most useful thing anyone could tell me this month.

Thank you very much! ❤️