Garageband
Does anyone know if Garageband has the same capabilities as the Amazing Slow Downer? I have garageband and when I slow the tempo down it sounds like the pitch slows down as well, and some of my music won't slow town at all.
All slowdown software distorts sound. The more you slow it down, the more distortion you get. This has to do with the way the software duplicates tiny time samples and strings them in a sequence to make the moment last longer - but instead of flowing to the next moment, it bumps back to the beginning of the moment that's been sampled, so you get some discontinuity that you hear as distortion (at least I think that's what happens, perhaps some knowledgeable tech-head will give a better explanation).
I haven't tried the Amazing Slow Downer, as I have the ability in other software I already own, including GarageBand, Adobe Audition, and Audacity.
Audacity, by the way, is free and does a huge amount of sophisticated stuff related to multitrack recording and sound tweaking. it's available for Mac OSX, Windows, and Linux, so pretty much anyone with a modern, mainstream PC operating system can use it (I can't comment on mobile device OS's such as iOS or Android).
On my laptop I use the program 'Best Practice'. Free, simple to use, separate speed and pitch adjustments (pitch adjustment in case you have a backing track in the 'wrong' key, looping function. Works for me.
You can slow the tempo of an imported audio file without changing the pitch.
Under the Control menu (menu strip at top of the screen when you're in GaerageBand), enable "Show Editor."
Turn on "Follow Tempo and Pitch"
At the bottom of he window, to the right of the transport controls (stop, go rewind, etc.) click on the leftmost icon and choose "Project" (metronome icon).
Now click on the number under "Tempo and slide the slider down to a lower number to slow the tune down.
Sound quality suffers, but you're listening for information, not beautiful audio.