yes thank you..i'll take a look at it now!

but i get the idea

IB sub is a hard one. You make a sub with stiff suspension and light cone to have good control and high power handling, and you get a high Fs sub that does not want to make sub sounds. You make the cone heavy to lower Fs and its harder to control at higher excursion, the sound can get muddy, etc. You put a stiffer suspension on it and lose efficiency, you put a larger motor on and it hits xmax faster. More xmax just makes it all worse. Someone correct me if I screwed any of that up.

When I do it I try to size the driver to the power I will use. Ideally you want to just hit xmax once in a while with the power you use, then you know you are getting the most you can. That assumes the driver will work well IB to its xmax, and some lower power subs can be more efficient for more db per wattage. I have looked a lot and still not found a good description of IB subs in technical terms, when I ran them a lot it was trial and error. My infinity seem to work ok but I have nothing to compare them to in this setup. They seem to like 50Hz and less.

My sub never gets even close to XMAX, no need to... I have over an inch of throw & I use maybe a quarter of that when a song really demands sub 50Hz output.

Subs, in my mind, in a SQ system are only supposed to fortify the sub 50Hz region. My sub is crossed over at 45Hz @ -24dB.

Distortion increases the further the sub is exerted as well.

My sub never gets even close to XMAX, no need to...

Distortion increases the further the sub is exerted as well.

I agree, that is why I used 4 subs because they sound nice, barely move, and have good output at normal levels. But when I want maximum output that is how I tune a system at that point. I don't use it often, but I still want the thing to pound in a good sounding way; to be capable of that if I feel so inclined...lol. So far I can't even hit xmax with mine...but can't afford time/funds to try lesser subs right now. They could possibly work better if more efficient.