Yes, the NES can have poor audio depending on your setup, don't seem to have any issues with the other emulators I use. If you have extra programs running in the background, the NES audio is even worse. I use wifi dongles on my Pi setups, and if I ssh into the system while the NES emulator is running, it messes with the sound also. The Pi 2 also made a difference for me, in fact I am replacing one of my Pi 1's with a Pi 2 this weekend for this very reason.