I NEED HELP??? Digital distortion issue???

[Analytical Man]

I recently bought an imac and i am running logic xpress 8 on it. I am using the Lexicon Omega unit as my mix/monitoring setup. When i record a track it sounds fine as i listen but when i try and turn up the mix monitor for playback it has this aweful digital distortion on it. Even when the track is not playing and there is silence if the monitor playback knob is on it has a bunch of distortion. The issue is not with the signals clipping because i checked all of them. Am i missing something obvious. I have been working on this issue for about 2 weeks and i am losing it. Thanks
-Shaun

[antichef]

What type of connection is it to your monitors? Do you have the same problem listening to the tracks with headphones?

[Analytical Man]

here is the complete signal chain. i have the lexicon running into the usb on the imac, and the monitors hooked up to the to the left and right out of the lexicon via 1/4 inch cables. There is a monitor mix knob on the front of the lexicon is what controls the playback. When i turn it up to here what i have recorded i get that distortion along with the recorded music. I have checked all of the signals, everything is good. The preferences are set to core audio and to the lexicon usb device. The computer seems to recognize it. Any further help would be greatly appreciated. Thanks
-Shaun

[antichef]

I don't have the Lexicon, but I think this is worth checking out -- on your mac, go to Finder -> Applications -> Audio Midi Setup, then on the Audio Devices tab (the default) select the Lexicon device, and try changing the Clock Source setting - the best choice would probably be to choose the unit itself, which would be "internal" or something, and *not* "Built-in Microphone" or "Built-in Input" which would be slaving the unit to the computer's clock.

My MOTU has a dedicated little program that manages the settings as well (and the Lexicon might too), but I'm pretty sure this control-panel-like application works as well.

Then, in Logic Express, open File -> Project Settings -> Synchronization -> Audio -> and set Audio Sync Mode | Core Audio to be "External or Free" - that'll stop LE from trying to override the clock setting you put in the other place (I guess look again to make sure it didn't change when you first opened LE).

All this is under the assumption that somehow the Lexicon is getting an incompatible clock signal from somewhere.

Sort of shooting in the dark here -- good luck.

[Analytical Man]

well thanks for the help. turns out i had everything hooked up right, just had a lemon Lexicon unit. Returned it to G Center and got a functional one and now everything is sunny. Got 4 gigs of ram in this bad boy and it rips. Now if only i could get my ez drummer recognized in Logic. Any thoughts on that.
-Shaun

[adamangler]

not so sure about it being a lemon.

i have 2 computers 1 runnin vista 1 runnin xp

i installed the unit on both, same settings and everything

on vista it playsback fine, on the xp machine it has the distortion?