I ran 1/3 octave narrated tones on the sub this morning. I already have 40hz cut nearly 14db to compensate for cabin gain. 40 and 50 are a little bloated while 25, 31.5, 63, and 80 are somewhat flat with each other by ear. No need for an rta to quickly get an idea of what's going on. Now that I have somewhat of an idea of what the sub is actually doing I can get it close enough with eq. I must say that the sound of this sub is growing on me. It's clean and snappy. It performs just as expected where it's 100% sq and about as terrible as it gets for spl. It will shake things up a little and the gain on my amp could probably come up more without clipping. This Alumapro seems to be more power hungry that the ID15v3. I'd like to build a 4th order for this Alumapro and hear it in the box it was intended to be in. Stay tuned, that might actually happen. Chef said he had the bp12 bandpass setup and it was AMAZING.