Just for the hell of it, I ran the RTA on my system as it sits, nothing more than the Pioneer head unit, Memphis 2.75" dash speakers and bone stock base 6.5" door speakers.
I used my Dell laptop running Room EQ Wizard (REW) into the head unit via the new AUX input I installed in the dash cubby with an AudioQuest 1/8" cable, and the miniDSP UMIK-1 mic.
This isn't a perfect session as it's about 210*F outside as well as nosy neighbors wondering around (stinkin' apartment complex). So I had the engine running, AC running and me sitting in the passenger seat. I tried keeping my legs and laptop out of the way of the passenger door speaker as much as possible. This means I was sitting Indian style in the seat (which was a bit uncomfortable) and the laptop folded in half on my stomach.
To overcome ambient noise of the engine and AC running, I ran the pink noise up around 90 dB. With the pink noise playing, I really couldn't hear the engine and definitely not the AC as I had it running on its lowest setting. Though from the looks of the measurements, the mic was still picking up engine/exhaust noise, so just ignore the measurements from about 50 Hz down.
It's quite obvious in the graphs that I'm getting a fairly decent suck-out between 3 kHz and 6 kHz.
Other than that, it sounds amazingly good! Doing nothing else other than tweaking the EQ for a little flatter response, it made a huge improvement! I'm very impressed in the sound stage, imaging and width as well as the overall sound, all of which improved with the tweaking.
I know this sounds crazy, but I hope the Stereo Integrity setup sounds as good, only because I love all of the mids and vocals up on the dash.
Anyway, a few pics...
The red line shows the initial curve before tweaking...
And what the EQ looks like...
