I am recording a podcast, and would like to hear everything that is being said through headphones in real time. Here's my setup. MXL 990 condenser mics into the mic jacks of a Mackie VLZ series mixer. An instrument cable from the out port of the back of the mixer, into the instrument input of a presonus firebox. Firewire out of the firebox into the USB port of a macbook. I would love to be able to hear us on headphones while we're recording live, but I'm a little new when it comes to audio engineering. Could someone please help?