Notes you can’t delete
Take a musical idea out of everything a small model is ever trained on, and it rebuilds the idea anyway. You cannot un-teach it. This is the music, the numbers, and the whole build — from a single note up to an entire instrument.
Delete the concept. It comes back.
The same experiment, run at every scale we could reach. Edit an idea out of the training data, train a model that never sees it once, and measure how strongly it still expects it. The bar is how much came back.
The idea doesn’t live in its instances. It lives in the grammar around them — the key, the root, the riff, the groove — which the edit never touches. So the model infers it back. The only place deletion finally bites is a trait so novel that nothing else in the data implies it.
A model wrote these drums for this riff
Strip the drums off a real metal riff and let a model — one that had the drums torn out of every training example — fill them back in, beat by beat. Flip between its drums and the real ones while it plays.
The model's kicks land on a guitar onset 100% of the time — exactly like the real drums. It learned that the kick locks to the palm-mute chug, and used it.
Rendered through a GM soundfont from symbolic MIDI. Full experiment, the double dissociation, and the honest caveats: Rebuilding the bass and drums.
Every experiment, as deep as you want
Each finding has its own page with a depth dial: the music and the punchline for a casual read, the setup and the numbers for a builder, every measure and caveat for a researcher.
Rebuilding the bass and drums from the riff
Reconstruction between instruments: the bass rides the guitar's pitch, the drums ride its timing, and a scramble cleanly severs one without touching the other.
bass 6× · drums overdeterminedMetalThe tritone you can't delete
Metal has none of the functional harmony we thought did the rebuilding. Delete the b5 anyway — it comes back at 99%.
99% rebuiltJazzThe blue note you can't delete
Erase every blue note from the training data. The model still expects it, exactly where a soloist would bend one.
97–98% rebuiltMetalCutting a genre from the family tree
Delete a whole genre. Black metal rebuilds from its thrash siblings; djent's novel sub-bass is the one thing that won't.
shared rebuilds, novel deletes