Ok, so its been a while since my last post, there was a vacation and then a little storm called Sandy that got in the way of my progress. I have been playing around with REW but a crappy external mic i found has some sort of constant 60Hz hum that shows up so I'm stuck using the internal laptop speaker for now. not sure how it could be the mic so it may just be a flawed design in the laptop external mic circuit picking up that hum internally. I have not calibrated REW yet but I was able to verify a 16Hz tone using the real time analysts tool so that is nice even though it is below the current tuning frequency of the box.
Another thing I did was eliminate the POS high-low converter and replace it with a hand made (by me) high-low converter that is basically just a cutoff RCA plug with a 68K Ohm resister on each line to build a voltage divider at the amp input. The motivation for this is with my low Hz test tones it started to clip at the input of the amp. I tested a few things and narrowed it down to the crappy high low converter. Its amazing I can actually hear that the response is flatter than before after replacing it with my own device.
High Level Out -> 68K Ohm inline hot wire -> Male RCA out.
here are some pics and ill update another post i have about high low converters.
now to find a decent mic and hope that that 60Hz hum goes away.