After 5 minutes, all sound goes all grainy and distorted PLEASE HELP!!

Question

Hello people,
After 5 minutes, all sound goes all grainy and distorted!! Using Logic Pro 8.
This happens especially if I crank the speakers semi-loud. This is not a problem with the speakers as Itunes plays perfectly. I have no idea why this is happening! The problem disappears when I restart Logic only to reappear again 5 minutes later.
The sound goes super grainy and I cant really make out anything. Is Logic overloading the sound card or something? Although this never happened before and it is a Tascam US-144, usually very good.
If anyone knows why this is happening I'd really appreciate some help.
Thank you, all the best!!
Tristan

Answer 1

Hello and thank you for your time! The speakers I do believe are active in that they have their own power source. They are Behringer MS40's. The headphones indeed also suffer the graininess, any sound that comes out of the sound card via Logic!
At the moment the buffer is at maximum of 1024 with a large Process Buffer Range as it runs more smoothly this way. Does it help if I change this? Is there any other settings I can try changing which may realistically fix the problem? Unfortunately the technical side is not my forte, being a songwriter rather than a producer.
Yes Itunes also plays via the Tascam with perfect results!
Unfortunately, this distorted sound and graininess happens with every Logic project, the more Audio tracks it seems, the more frequently.
You have been very kind, thank you. If you have any ideas of how I can fix this then please do let me know.
PS. Something I noticed is that this started happening after some guy screamed into the Mic for a laugh whilst recording and the project instantly crashed. I do believe there is a connection between the Audio tracks and the grainiess rather than the MIDI tracks.
Sometimes I can get a good 15/20 minutes of working time before the sound becomes distorted again! Which is what I've been doing these past 2 days.
All the best,
Tristan