Audiobus: Use your music apps together.
What is Audiobus? — Audiobus is an award-winning music app for iPhone and iPad which lets you use your other music apps together. Chain effects on your favourite synth, run the output of apps or Audio Units into an app like GarageBand or Loopy, or select a different audio interface output for each app. Route MIDI between apps — drive a synth from a MIDI sequencer, or add an arpeggiator to your MIDI keyboard — or sync with your external MIDI gear. And control your entire setup from a MIDI controller.Download on the App Store
Audiobus is the app that makes the rest of your setup better.
Formulas for Audio Production
I don't know about anyone else (a good starting disclaimer, right?), but over time I've had to work out formulas for various processes, particularly time related. I can't be the only one, so I propose a repository for these formulas. I'll start. I use these when trying to create audio loops:
Determine the BPM when you know the number of beats and the length of a clip (in seconds):
60 / (length/beats)
Determine the speed change% (in TwistedWave for example) when you know the current length in seconds and want to make it fit in a specific number of seconds:
(Old length / Newlength) * 100
Determine the speed change% (also TwistedWave) when you know the clips current BPM and want to change to a new BPM:
(New BPM / Old BPM) * 100
Determine the correct length (in seconds) when you know the number of beats and the BPM:
Number of beats * (60 / BPM)