HOLY COW!!! THIS IS THE MOST AMAZING THING I'VE EVER HEARD IN A HOME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :P :P :P :P :P
If you can't tell I’m incredibly excited, ha ha
I have not yet equalized anything and the sound produced by these 4 18" woofers is beyond phenomenal. I've been searching from something that is able to both give me the details of bass guitars and harmonics generated by rhythm guitars while being able to produce infrasonics, kick drums, etc., all at terrifying levels with amazing clarity, and I've finally found it. The clarity is unreal, but not as unreal as the weight and quality of the bass. SPL? TOO MUCH FOR MY HOUSE!!!!!!!! Watching transformers is now an exercise in brutality, but not at all overbearing like my previous high quality DIY box setup, like things are really really happening and creating natural sounds in my living room. My DIY setup was impressive, this IB setup is 4 times as tactile as it was and understand that the DIY box setup moved about 3 times as much air as a velodyne 18" model at 20hz (tuning of the DIY setup). The IB is louder, cleaner, and realer. I honestly just can't describe it but being all the hard work that went into it I was simply ecstatic to hear the results!
Building the box in place under the crawl space wasn't too bad but I'd suggest if you're not a bigger guy and have a bigger friend at your side that you consider building the box outside (I’m about 200lbs and so is my buddy who helped, made things a lot easier moving around the baffle boards with the woofers in place in the crawlspace). I ended up with some gaps, some as large as 1/4" by building in place and being far from an expert wood worker but having sealed them up with caulk from the inside and outside air is not leaking through these areas. And if it is then it's not anything I’m noticing with the amount of output coming from this system. I did manage to bridge adjacent floor joists also to prevent any horizontal movement in them. Even at higher levels there is almost no vibration in the manifold boxes at all, simply amazing!!! The house however is another story but it seems to be all coming from sound pressure. Pretty much everything moves on every surface of the house when things get cranking, ha ha!!!
Once I EQ this setup and calm down from the overall excitement it's generated I will report back with a more detailed review of the system.
Anyone on the verge of going with anything other then an IB just do yourself a favor and pull the trigger. I just can't imagine doing anything else. Sure you could build a behemoth ported box utilizing four 18" woofers and have even more output but I assure you that you will not be able to use it considering this IB can produce more spl then my new construction very well built home can tolerate!!!! My living room is 22 x 12 but opens up to the entire living area (kitchen, dining room, entrance) to the house and has a 10' vaulted ceiling. I estimate the volume to be around 3000 cubic feet but it's quite a bit more considering the rear opening. My home is very very very well sealed however as it breaths through a hepa filter filtration system, something my home builder does so this may have some influence on my results.