No Sound after awakening from sleep (Mac OS X)

Yes, I used search on forum and found some similar threads. But still, i have a question and i want to understand it clearly)

I have:
Model: iMac 27” (Mid-2011)
OS: 10.8
CPU: 3.4 GHz Core i7
Memory: 8GB (2 X 4GB)
M-Audio Products: FireWire 610 (2.3.3 driver)

When my Mac returns from sleep it doesn't play any sound. And since i am using alarm on Mac, i can't shutdown it, only put to sleep.

So i ask youth answer me, can this problem be solved? Cause if not - i will need to exchange this interface on money in two weeks(

Sorry for my english(