There have been a few reports of audio problems with mainly iPad 3 used with an external audio interface, sometimes causing audio glitching or stuttering as iReal Pro plays.

We’ve added a new hidden option in version 5.0.5 (and above) of iReal Pro for iOS that allows you to reduce the CPU usage (while losing some features like position marker).
Go to Settings then tap the Version number ... 7 times for the Low CPU mode option to appear in the General section there. Turn it ON.
This should allow you to have clear sound through the audio interface while using iReal Pro. For headphones etc. (not using your interface) you can turn it off (and the position marker etc. will again appear with the Player).

Note: if you Reset All Settings, this option will reset to off and hide, so use the 7 taps again to reveal it again if needed.
Although this option works for other iPads, our tests show it probably is not necessary to do this for any other model (including iPad 1 which should not need it).
Again, only if you are using an external audio interface and experience audio problems should this be necessary.
This will be relevant to only a few users.