Why I Built Music Slow Downer (and Why It's Free)

Published November 5, 2026 • 4 min read • By Andrew

Hi. I'm Andrew. I'm a software engineer by trade and a guitar player the rest of the time, and I'm the person who made Music Slow Downer. Not a team, not a startup. Me, in the evenings, on my own laptop.

The itch I was scratching

Like most guitarists, I learn a lot of songs from listening to them online and from recordings. And like most guitarists I kept running into the same two problems:

• The part I was trying to learn was too fast to hear properly, and I wanted to slow it down without the pitch dropping.
• The recording was in a key I didn't want to play in — the band was tuned down a half step, or I wanted to sing it somewhere comfortable, or I just wanted to work it out in a shape I already knew.

There are tools that do this. Most of them cost money, and some cost quite a lot of money. I looked at them and thought: I can build this... so i did

It runs in the browser, it uses open-source audio libraries, and the hard parts have already been worked out by people cleverer than me. So I built it for myself first, and once I thought it was useful I put it online.

Why it's free

Here's the honest reasoning.

Musicians, on the whole, don't have a lot of spare money. Plenty of people who'd get real use out of a slow-downer are students, hobbyists, people in a covers band for beer money, or someone learning their first instrument at 45. Asking them for $50 for a utility feels wrong to me when I know how little it costs to run.

I also had the skills to build it, which is a kind of privilege. I didn't have to pay anyone or raise money. I just had to spend some evenings on it. Giving the result away to people who'd use it seems like a reasonable thing to do with that privilege.

So there's no account, no trial, no feature you have to unlock. Everything the tool does, it does for everyone. The audio never leaves your device either, because I never wanted the cost or responsibility of storing anyone's files.

How it stays running

The site shows a few small display ads. They cover the domain and hosting and don't amount to much beyond that. I'd rather have them than put a paywall in front of anything, and I've tried to keep them out of the way of the actual tool.

Beyond that, there's a Buy Me a Coffee link. I want to be careful about how I say this, because I don't want anyone to feel got at.

You don't owe me anything. If you use the tool every day and never send a penny, that's completely fine and is exactly what I built it for. But if it's helped you learn something, and you've got a few quid spare, a coffee is a genuinely nice way to say "this was useful" and I do drink a lot of it!. It helps with the upkeep and, honestly, it's just encouraging to know someone out there found it worth it.

Other ways to help that cost nothing

If money's tight, these are honestly just as valuable to me:

• Tell another musician. Word of mouth is how a free tool with no marketing budget gets found. If a bandmate or student is struggling with a fast passage, send them the link.
• Tell me when something breaks. I test on the browsers I have, which isn't all of them. A quick bug report through the contact page saves me guessing.
• Tell me what you'd want next. The frequency isolation and loop export features both came from thinking about what I'd actually use in practice. I'd rather build things people need than things that sound impressive.

What's next

I'll keep improving it as long as people are using it. I've got a list of things I'd like to add and a longer list of things I'd like to fix. It's a spare-time project, so progress comes in bursts, but it isn't going anywhere.

Thanks for reading this far, and thanks for using something I made. Now go and learn that solo.

— Andrew