building enclosure, port location?

Put the port on the same side as the subs in the middle. Computer programs (well most of them) won't tell you how the soundwaves will travel specifically but putting the port in the middle will achieve the best results on the reflecting waves in the enclosure. If you want to put the port on the side of the box, keep it as close to the side of the box as the subs to keep the imaging stable.

Then your next issue would be to control the reflected waves within the box. Sound absorbing materials (not sound dampening) lining the walls and the port (not on the inside of the port) will allow the side port to function at its best.

But for maximum effect, stick with the port in the middle. It's a known, proven system for big hits.

Good Luck!

bellsracer, let me get this straight:  you and your crew performed scientific testing on sub enclosures, at least one of which had the port on the front at the side, and at least one that had the port dead center between two subs.  And being a controlled test, both enclosures, bracing, drivers, power input, source material, etc. were identical.  Is this right so far?

So now, what is perplexing:

You said that you found a difference in Fletcher-Munsen curves between the two enclosures?

When it came to power draw versus SQ for flatline, we found that during our test between 80-125 Hz @ 100 db the curve lifted slightly in order to match target spl properly.

After absorbing the sound, we found a 2 db increase in spl and had to drop the power a bit in order to match target spl. This was consistant with the calculations that Tek and D did to figure out what was happening to the soundwaves reflecting in the box.

To be honest I'm not 100% sure what the equations are or anything but I do remember seeing their book they filled with all the calculations. It was about 120 pages of calculations and 15 pages-ish of written notes.

Tek made us crossovers that bandpass the targeted tone with 24db/octave cuts +-2Hz from target. It was kind of strange and I don't understand it all myself, but that is their results.

I didn't think that the overkill deal would get this attention... It was more of a chindogu (useful but not practical idea)

As for the technology in the shop, most of our testing equipment is the same equipment used in SPL and SQ competitions. A Gateway (top notch) computer controls our sound test equipment. TPI 440s help us double check what the equipment is doing while installing and fabricating. It's nothing wow worthy so much as it is just used a lot.