This problem started since i updated my iPhone 5 16GB and iPad Air 32GB Wi-Fi from iOS 7.0.4 to 7.0.6 (iOS 7.1 still have this problem):
i'm a DJ and using my iPhone and iPad as mobile but powerfull dj setup (with installed DJ Player ios app (http://djplayerapp.com)) and connected Vestax VCI-400 dj controller (with separate power adapter and powered hi-speed usb cable) via original Camera Connection Kit.
MIDI touch responce was perfect until upgrading to iOS 7.0.6. After that i got audio latency issues.
For example: i press to any button or moving crossfader and jog wheels for scratching on dj controller but sound starts just after a few seconds. DJ controller works fine (with usual aftertouch audio responce) with other music apps instead this one.
By the way: Connected AKAI MPK25 midi keyboard responce is OK in DJ Player and in other apps too (with separate power adapter and connected CCK via USB hub) without any problems after iOS updating on both Apple devices.