Question Audio recording problem with different apps

Trying to record an audio on my nexus (lecture for example) and having some issues with it.
I start record and then leave it with screen off for an about half hour or more (plenty of space for the file). when I start to listen to the audio that I recorded, the sound is not clear with gaps.
Checked the recorded audio on my PC also and still same result - awful sound with gaps.
It is not app related because I tried already 5 or more of them (apps that work great on my old HTC desire).
I'm using stock rom (4.4.2) with Franco kernel - without modifications to it.
Any suggestions ?