Got to be one of the prime candidates for most useful iPad app so far for music creation. The AC-7 Pro is a Control Surface emulator designed for controlling Logic, Digital Performer, ProTools or any other Mackie Control ready DAW.
Setup
Setup is a little fiddly - in that you need to download translation software - the DSMidiWifi server and a little MidiPipe utility on the Mac and have them running and pipe the MIDI in and out of the ports they give you. Instructions are all on the Saitara website - the process is very similar on the PC.
Latency
Communication is handled over WiFi - I set my airport card in the MacBook Pro to create its own network, so I avoided any additional routers and latency that might introduce, with a more complex and heavily trafficked Wifi network, I suspect there may be more of a lag.
Win
Where this shines is for remote control of the DAW - say if you are playing a drumkit or a modular synth setup and want to record and control away from the computer. Its also pretty good for quick automation writes, though nothing quite beats an actual physical fader it will get the job done.
Fail
Not so hot are the other control functions - editing EQ, effect sends, plug-in parameters is all a bit unintuitive for me, though this is perhaps a limitation of the Mackie control format - perhaps they could introduce another screen of pots for more detailed parameter control, after all - its not like the knobs will cost any more..
End
This actually a useful application, something that isnt just a novelty but is more of a utility - I can see a lot of potential uses for this. A lot of people with larger setups go to all the trouble and hassle of running long USB and monitor cables to other areas room to allow control of the DAW away from the computer, with the AC-7 Pro, you just dont need that and it it portable too.
Assuming you already have an iPad, for $9.99 (£5.99) this is a a no brainer.