ok stupid question, but im just curious off the results. I take a purely spl sub, like a kicker, and i put it in a sealed sq type box. Sql or something just really f*cked???
well, purely SPL subs like the RE MT, or Solo X aren't really designed for accuracy or detail, tonal quality, or highly detailed motor control. They're made to move a lot of air, so even using one in an aperiodic enclosure or something similar to control the sub as best you can won't result in a really good sound. You'd be better off using a 'supersub' class driver aimed at both fairly high SPL and very good SQ, and putting that into a good AP box, like a triple X from RE, or an Eclipse Ti. then you get a really good sub for all around specs, and you use the type of box to focus that sub on the goal you're after, like SQ that can still get very loud. that's exactly what I did for my car in fact. I used two RE XX.X 12" in aperiodic enclosures with plenty of power. the result is amazing driver control, elimination of 2nd and 3rd order harmonics, and only a slight -3dB decrease compared to a sealed box for SPL. But believe me, those two subs still get loud enough to hurt. You'd never complain about a lack of SPL with them for listening purposes.
With that combo, the effect is that you're taking a sub that has crappy SQ in the first place and lessening it's output. SPL type subs are optimized for ported and bandpass type enclosures, and the results in a sealed box are worse than if it were a sub designed mainly for sealed enclosures. If anything get a SQL sub and work with that.