Recently while experimenting with the excellent MIDI instrument, Gestrument, I rapidly found my iPad misbehaving in various ways and decided a compromise was in order. Using my iConnect MIDI 2, I can send and receive either audio or MIDI to and from my iPad. I decided that I wanted to create a piece using the Gestrument instrument but with desktop samples (which are STILL head and shoulders above any sampled instruments on the iPad).
Gestrument is very expressive and with multi-touch gestures will send MIDI notes, velocities and varied pitches, etc. It can control multiple MIDI channels all at once and is capable of making some very unique sounds.
I wanted to make a jazz piece and use some Native Instruments Kontakt samples. I chose the MM Bass and the MKII electric piano for the background of the piece (both part of the Komplete bundle from Native Instruments). I wanted to use gestrument to send chords which is not something it does easily. Rather than wrestle with multiple voices on Gestrument, I sent one instrument into a "Track Stack" in Logic X and then sent the notes to the Bass on one track, a MIDI chorded piano on a second and a syncopated arpeggiated piano on the 3rd track. This set up the basic bass and piano rhythms in the piece very nicely. By playing the notes and articulations on the iPad, I recorded the resulting MIDI into the track stack which played back on the 3 sub-tracks in Logic.
For jazz drums, I find the drum tracks a bit lacking in Logic, so I resorted to some excellent Jazz looped drums.
Once this was all done, I set up a few saxophone tracks and played various rhythms in the same key (Eb minor blues) as the rhythm and then mixed, tweaked and mastered on Logic from there on out.
Say what you will about Cubasis or Auris, Logic X is still worlds easier to work with multiple MIDI channels with or without the iPad.