He’s using an app called MIDI Guitar 2 by Jam Origin. It converts the audio from your guitar into MIDI note information that the MINI-SYNTHESIZER app reads – it can also pick up on vibrato from the guitar strings.
This is a known issue with iOS 8 and it will be resolved with the first update coming soon in the App Store.
For Mini-Synthesizer app support, you can also contact us at minisynth @ ehx .com
The ‘Solo Analog Synth’ preset will be available in the first iOS update coming soon in the App Store. Hang in there!
For Mini-Synthesizer app support, you can also contact us at minisynth@ehx.com