Apps similar to PaulStretch include ZynAddSubFX, which is open source with a free version. Other options are Amazing Slow Downer, BestPractice, Audiophile TuneLite and Reverie - Ambient Soundscape Generator. In total there are seven Music Production Apps like PaulStretch for Windows, Mac, iPhone, iPad and Linux.
ZynAddSubFX is a fully featured open source software synthesizer capable of making a countless number of instruments, from some common heard from expensive hardware to interesting sounds that you'll boost to an amazing universe of sounds.
Romania
EU
Change the speed of the music - from 20% (one fifth speed) to 200% (double speed) without changing the pitch.
SwedenEU
BestPractice is a tool especially for musicians to slow down or speed up music, either from a file or directly from a CD while keeping the pitch at the correct height. On the other hand the pitch of the music can be changed without affecting the temp.
TuneLite is the perfect music practice app for singers, dancers and musicians of all kinds. Learn to play, transcribe and practice songs by slowing down the tempo, adjusting pitch, repeating loops using your favourite tracks.
Reverie turns any audio file into endless ambient soundscapes for music production, game audio, content creation and sound design. Pick a style, generate a unique render every time.
FranceEU
A free, open-source browser extension that transposes, slows down and loops any audio or video in your browser, so you can practise music along with it.
