Re:Show HN: Chipmunkify – I used ML to solve audio's dumbest...
by treelover on Sunday April 12, 2026 @11:42PM
(#47747313)
You know those YouTube channels with millions of views that are just popular songs, but chipmunk? They sound awful because they pitch-shift the entire track.
I fixed it.
The pipeline: Upload an MP3 -> Demucs isolates the vocals -> Rubber Band pitch-shifts them into the rodent register -> FFmpeg glues it back together. Hosted on Modal.
Guardrails protecting my $5/month Modal budget and net worth:
* 10MB max upload
* First 30 seconds only (Demucs is computationally brutal)
* 3 requests/IP/day
I delete your files immediately: not out of principle, but because I genuinely cannot afford to store them.
If the site throws an error, you've assassinated my budget and I will pour one out.
Try it out and let me know what you think. I suggest using a song that you love!
Re:Show HN: Chipmunkify – I used ML to solve audio's dumbest...
by blemis on Monday April 13, 2026 @05:42PM
(#47758193)
love the budget-constraints section, feels way too familiar. i'm running 7 NLP models on an $11/month VPS for a different project and every architecture decision ends up being "what's the cheapest way that doesn't burn my bank account on one runaway request."
question — how are you handling demucs cold starts on modal? cold start was what eventually pushed me off modal for a request-response
use case. the user is staring at a spinner for 20-30s on first invocation and it kills conversion. did you solve it or just eat it because the rest is so computationally heavy anyway?
I fixed it.
The pipeline: Upload an MP3 -> Demucs isolates the vocals -> Rubber Band pitch-shifts them into the rodent register -> FFmpeg glues it back together. Hosted on Modal.
Guardrails protecting my $5/month Modal budget and net worth:
* 10MB max upload * First 30 seconds only (Demucs is computationally brutal) * 3 requests/IP/day
I delete your files immediately: not out of principle, but because I genuinely cannot afford to store them.
If the site throws an error, you've assassinated my budget and I will pour one out.
Try it out and let me know what you think. I suggest using a song that you love!
question — how are you handling demucs cold starts on modal? cold start was what eventually pushed me off modal for a request-response
use case. the user is staring at a spinner for 20-30s on first invocation and it kills conversion. did you solve it or just eat it because the rest is so computationally heavy anyway?