Mbox 2 mini and mix knob

[Greg555]

When Im on the road for portability I use the Mbox 2 mini for recording guitar.
The guide for the Mbox states to use the mix knob to balance the input thats being recorded with the output of Pro tools track playback. But... when I turn the mix knob to the left to hear my plugged in guitar I do not hear the existing tracks in pro tools.

guitar plugged into input 1 and track output set to main out 1/2.
I also dont understand the latency thing. I have to set the HW buffer size to 128 to avoid the delayed input. When I used Sonar I could disable input monitoring and not have any delay. isnt there a way to disable input monitoring in PT?

Greg

Alienware area 51
portable setup

win xp home
Pro Tools 7.4
V One Toontrack sample player
Mbox 2 mini
Korg pandora effects unit
CPU Pent 4 2.9 gz
3 gigs ram
2 hard drives both 7200 rpm
Pro tools sessions stored on HD without the Win OS
Traveler guitar electric 6 string
Mogami audio cables balanced
Nothing running that doesnt need to be running
A pair of sony $20 headphones

[BillDog793]

The mix knob on the mbox basically lets you set the ratio of the signal from the input (unaffected by the computer) and the signal from the computer. So when all the way to the left you are only hearing the input coming in. Latency is the time it takes the signal to go from your guitar to the computer, write to the hard drive, and then return back out thru the outputs. The smaller the H/W size the less amount of data the computer is looking at, so when you use a small H/W size you get less latency/delay but less comp processing, and with a high H/W size you get the opposite. Hope that helps!