Don’t be put off by terrible example tracks ...
My (uninvited) advice to the developer:
1) start again with example content (royalty-free loops maybe?) - you really aren’t doing yourself any favours with the current vocals (sorry)
2) reconsider the novelty FX - I can’t think of any examples where anyone would want to add FX to a finished track or even a training loop - you’d be putting effects on the instrument you were playing live - never on the backing track.
3) focus your efforts on improving the pitch change algorithm - this is a useful feature but l get lots of audio glitches even on a modern iPad Pro
4) starting/stopping the audio via cable connected midi devices as well as Bluetooth midi would open up using this app with other pedals (iRig stomp, HX stomp etc)
5) Open up import from Dropbox/Google Drive. Whole tracks may be on iTunes but loops/jams almost never are (so this is particularly an issue for your other scales app)
Some good potential here but some fixes and content required - very happy to revisit this score/review if the app is improved.
Response from developer
Hi, thanks for your detailed feedback. Midi and Dropbox is already on our wishlist. We are non professional musicians as you already recognised in the samples, but there are millions of us. That’s why we keep the unprofessional sample songs. :-) The effect section is not made for backing tracks already mixed, but for your own second part of a song you like to play along. But thanks again for your comments, this is done very often!