I've had this problem in a couple of Logic projects recently, but so far only in existing projects. Opening a new project and setting up to record is fine. But adding an audio track to an existing project and recording guitar gives me a slap-back echo effect, even with no inserts or sends on the channel strip I'm using. I haven't consciously changed any settings within Logic or on my M-Audio Firewire 410 interface, so it's baffling. But I'm frequently baffled, so I hope you might have some obvious places I should be looking to make adjustments.... Logic 9.1.3; OS 10.6.7; Mac Pro tower, 2.8 GHz Quad-Core Intel Xeon with 12 GB RAM.

If you're monitoring through Logic, enable [b]Software Monitoring[/b] and make sure the correct input in the Firewire 410 is muted or has the fader pulled all the way down. If you're monitoring through the Firewire 410, turn Software Monitoring [b]OFF[/b] in Logic and make sure the correct input in the Firewire 410 is [b]NOT[/b] muted and has the fader up.