Duet out of sync

I’m recording 2 tracks of alto recorder. I record 1 track using Cubasis metronome and ipad internal microphone. I then add a new blank audio track and record onto that. I use headphones in the iPad headphone jack, and I also monitor the first audio track through the headphones. Everything sounds fine during the recording of the second track. However, when I then listen to both tracks together, they start out in sync, but after a few measures, the second track slowly falls out of sync with the metronome as well as the first track (which seems to stay in synch with the metronome). By the end of about 60 bars, the second track is about a half a bar out of sync (the second track finishes about a half a bar before the first bar). Can anyone help me? This is about as simple a 2 track recording I want to make, and it’s not keeping in sync is very disappointing. Thanks.

I have posted a similar phenomenon


…are you by any chance using an iPad2 ?
I suspect it’s got to do with the limited RAM and CPU of the iPad2 …but have no way of proof so far.

No, it’s not an iPad 2. I’m going to try fiddling with the quantization and snap/grid settings.