There are lots of reasons to use one sub instead of 2. Space was mentioned, cost is lower, but room to upgrade is also there. If you have room for 4 12s, but you get 2 good 12s instead, you might've been louder with 4 cheaper subs, but now you can put 4 of the better subs in when you get more money. lots of reasons.
I actually had (like your example) 2 type-rs sealed in the trunk of a mustang on 1krms. I put the same power on a single type-x ported and gained quite a bit of output. Really nice looking sub too imo.
and wouldnt you get more output switching to a ported from a sealed anyways? maybe that was what caused the difference, not the subs themselves.
so basically, getting one good 1000rms sub, will be better quality then 2 500rms subs? i don't really care about spl, i want sq...(one type x will sound better than 2 type r's?)
I prefered the type-x in every way. It was tuned to 32hz. The box for 1 ported was smaller than the 2 sealed, and it had a much nicer, deeper sound. It still sounded articulate, but really had a lot more down low. I had the X in both ported and sealed, and I really liked ported much much better. That was my point tips, to why some people may choose 1 sub- Although it doesn't mean 1 more powerful sub will be better than two meant for less power in any way. It just worked out that way for me.
Now it's going in the wifes car when I get around to building her a nice box
