We have a protools 7 setup here at work, with an MBox. Everything works great except when you monitor the audio you are recording, it has about a sec. long delay. Now, we're just running the box off usb. We have a microphone running directly in using phantom power from the mbox. The speakers we're using to monitor are running out of the mbox as well as the headphones used for monitoring. Any ideas?
Sounds like USB latency, but it shouldn't be one whole second to begin with. You can reduce that by adjusting the buffers in PTLE and also by making sure you're in Low Latency mode. It'll still be somewhat delayed because it's USB. Most people adjust the MIX knob on the front of the mBox to source to reduce the delay. Make sure you play with that as well.
All that stuff is in the manual, btw, and you can also get good info from the Digidesign DUC forum.