Strange monitoring problem

I'm hearing a strange effect on my vocal mic. It sounds sort of like the audio is being sent to headphones twice with a very slight delay between the two. Sort of a chorusy/phase sound effect. There are no effects on the track. Its not there on playback, just when I'm monitoring or recording. I've tried different mics, different patch chords and different mixer channels but the same thing happens, but im not totally surprised here as it not there on playback. I'm using a Macbook pro with osx10.7.5 and a Makie Onyx1620i mixer. I've also tried reinstalling Logic and updating it so it can run on this os but the problem persists.

Any suggestions?