May be of use to some other Apple device users just came across this today
Change the speed of audio files without changing the pitch. Listen as you drag the waveform. Play at zero speed. Transpose to another key. Loop. All in an incredibly responsive and easy-to-use app. Ideal for transcription, learning songs by ear, or just listening to your music library in a new way.
Not sure? Download AudioStretch Lite for free. It's the same as the full version apart from a few feature limitations.
• Simple uncluttered user interface
• LiveScrub™ : listen as you drag/hold the waveform
• Keyboard/spectrum feature for transcription
• Flexible looping feature
• Load any song in your music library*
• Send time-stretched, pitch-shifted files by email
• Open Dropbox files and email attachments
• Speed range -2.50x to 2.50x, including zero speed!
• Pitch shift range +/- 12 semitones
• Instant freeze by tapping on speed display
• No ads or in-app purchases