Slow MP3
by Pekka Kauppila
(Pekka Kauppila Website)

Download from the
Author's Website

Operating System:
File Size: 532.27 KB
License Conditions:


System Requirements:

Java Runtime Environment 1.5 or higher

Last Updated: 2010-09-27
For more detail about software : Software Description
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Software Description

Slow MP3 is a musician's music player. It can slow down, transpose and transcribe songs on the fly. Need to learn a song in a different key from the original? No problem. Want to play a fast solo part over and over again, in half speed? Can do. Cannot identify a chord? Slow MP3 will show the notes to you.

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MP3 --> WAV --> MP3

Sometimes it does not work for specific MP3s. For my first doing an mp3-->wav conversion and then a wav to mp3 conversion (with Lamedrop at standard settings) helped. Mp3 transcoding directly to MP3 again (withou wav in between) did not work. Probably its an issue with some tags.


This program is awesome. It can take a while to recognize the chord progressions but well worth the time spent.


Wow thanks for such an amazing tool. My band and I are going to go nuts for it.

Everyone else's seems to be

Everyone else's seems to be working but I can't even open any files ... what kind of files can it support? It says "cannot read file" on mp3 track I selected and I've already figured it doesn't support .wav.

on intel mac

Got Mac OSX 10.5.8
had same problem with Java and frozen sliders.
Go to "applications"->"utilities"->"java preferences"
and change the order to have first (on top of the others) the latest available java.
Re-lauch the app.
Have java 1.6.0_26

Keep up the good work thanks for that great free prog.
Greetings from Greece.

Changing the speed

Hello. I just downloaded this program and it seems to work quite well so far. However, the main reason I downloaded it is because I need to learn a very fast metalsong on drums (no hating on the genre, please...). When changing the speed everything becomes quite hard to hear. I don't know how to describe the sound but it sounds more "metallic" than it should :p If there's anyway to make the song go smooth even when it's slowed down I'd love if you could reply to this post. Thanks in advance!

Makes stuff possible - fantastic

Love this. Am now (slowly) working through some Grappelli violin solo's..which I had no chance of even following the written music with before.

I can't get it to run on my mobile phone (I use it on my windows pcs)... Is there some particular phone os I should be looking for on my next phone to be able to use it? (my current one is samsung's bada..).

Saving files

So, I really want to save the transposed file in the mp3 format to use it later... How can I do that? It's just that it's kind of worthless if you canĀ“t save the file after the edition... Please answer me, I really want to know if I can do that with this application or if I have to get something different. Thank you

Answers to your questions

Hi, I'm the author of Slow MP3. Here's some answers to your questions. 1. The Jar file is Java executable, you need properly configured Java to run it. Most computers should have Java by default. 2. In some Mac OS versions of Java the sliders are not working, I don't know what causes that, and unfortunately at this point I don't have time to fix the software. 3. Some mp3 files indeed play as "chipmunk" versions, I've seen that happen but haven't investigated the issue yet. 4. I'm a bass player, so the transcribe feature works best with bass frequencies. High pitches are not be tracked very well.

Thanks for all the feedback! I'm now working with some other projects but at some point I might update Slow MP3 and I promise to take your comments into account.

Slow MP3

I also can't open mp3 files (as per another poster). I see no replies or responses addressing this (even the comment from the software author). Anyone have a suggestion?

Thank You

Great piece of work here. Been looking for this very thing and here it is for free. I thank you sir.

@ Pekka

Your software is as indecipherable as the crazy old man from Waterboy. Seriously though it's quite in accurate especially above 140 bpm

How do I get the keyboard to show higher pitches?

I'm trying to transcribe flute & whistle music and most of it is too high to be shown on the keyboard, even when I drag the pitch slider as low as I can. Am I missing something, or is this a limitation?

This is a very cool app, now

This is a very cool app, now where were all those Frank Marino records again...
An equalizer, possibly graphic would be a great add on.

Worked great for me. I

Worked great for me. I looked long and hard for a piece of software that could slow down a track, loop over a specific section of the track, and, most importantly, was free. This is all three in one, so it was perfect for me.

Great. Drag an MP3 in, and

Great. Drag an MP3 in, and it plays and loops simply and sweetly for me under both XP and Vista 64. Just what I wanted.


This is garbage. No exe file included in the download to even open the program. What a waste of time

Jar File

This is a Jar file which I believe works for symbian/java devices - i.e. mobile phones. here are the instructions on how to make it work on a PC/Mac:

Thanks a lot. It worked for

Thanks a lot. It worked for me.

The pitch of the song isn't

The pitch of the song isn't right but there's a transpose bar to fix that problem. It works, and it's free so very happy! It's pretty easy to use, just open up a file and mess around with the speed and transpose bars.

slide controls not working

I'm using the Mac version. I can get an MP3 file to play on the program no problem. It will play them at normal speed only, because the slide controls are not working. They will not budge. I've tried with the sliders clicking and dragging, double clicking, triple clicking, right clicking, absolutely nothing will make those stubborn things move. Nice to find a free program like this, but every single slide control - speed, volume, pitch - does not work.

Is there a way to correct this? thanks

I'm having the same issue

I'm having the same issue with the sliders. The program works perfectly on my MacPro 8-Core machine but the sliders won't work on my MacBookPro. It's strange because I have a similar issue with another program but the sliders work on the MacBookPro and not on the MacPro. Any ideas? Thanks!

can anyone help me get started

can someone who has used this before, give me step by step instructions on how to use the software. i am not computer literate and really need some help. thanks.

Here are the instructions

The instructions for using this software are at

excellent!! just what ive

excellent!! just what ive been hunting for. thanks so much.

Got it working, but it turns everything into the Chipmunks

I think it only accepts a certain bit rate. Either that or it is not optimized for the latest Java.

Uh...Not sure how to even

Uh...Not sure how to even make this work...
I mean, I drag it from my iTunes and it won't work. Then I open it directly from the music file and it says "unsupported file format". So if "Slow MP3" doesn't support, er, mp3 formats, then what am I supposed to do? Convert it to something else? If so, where can I go to do that?

Its probably an m4a file

Its probably an m4a file that you need to convert to MP3. There are alot of song formats that itunes supports other than MP3, but this only plays mp3 and wav files

Very lightweight and simple

Very lightweight and simple to use. I'm amazed at the sound quality of slowed down songs compared to other applications out there.
Just what I needed.

Rename the .zip file to a

Rename the .zip file to a .jar file or just go to the guy's website and DL direct from him.

how to get it working

i have just downloaded slow down mp3 now how do i make it work

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