Echo when mixing w/ Aggregate I/O???

[zsjordan]

I have this nasty delay when I plug my headphones into the headphone jack on my MBP and attempt to mix in PT9. I solo'ed my kick drum and can hear a delay of it, but it's not clear. It's a distorted verbed tone of the kick drum. The same sort of thing if I solo the hats. The problem gets better the louder I turn my OS volume up, but that can't be the solution as I'm using Shure 3x drivers and that volume will be too loud after a couple minutes of use.

If I switch over to my 002 and use the headphone jack on the unit, everything is crystal clear.

The problem only occurs with use of the built in headphone jack on my MBP. And the problem only occurs in PT9. Normal sounds in the OS sounds crystal clear.

Has anyone experienced this problem?