I have a pair of Polk Audio Monitor 10s.
Pic (they're in the front there angled towards the recliner I'm standing behind):

I have read that there are different sub models, but the one on this escapes me. Only thing I can see on it is Polk Audio (even that is only on the speaker screed/cover thing) and MONITOR10 in the top right cornet on the back. Above the speaker wire inputs there is a SERIAL: and then there is a piece of long plastic, with rounded edges covering it up for some strange reason.
So, I have no idea if they are 10a or 10b or what, I just know they have a 1inch tweeter, 4 or 5inch mid drivers and a 10in passive radiator. I found out that its a radiator when I took it out to have it tested because it was hardly doing anything and there was like no bass you can feel type bass with these speakers and I thought maybe the 10inchers were partly blown or bad or something, and then I'm like "Oh, they're radiators, no wonder they don't really do anything."
I hate how they have a radiator because I love to blast hip hop music, and I want bass you can feel, and to get to that level of bass you are basically on the edge of possibly blowing the mid drivers from them flexing so much. I can see both things of rubber coming in an out 3/4inch or so. They sound amazing on vinyl though, even with bass (as long as I turn up the bass knob most of the way on my old Sony receiver) because vinyl doesn't really do boomy type bass, just nice, deep, extended bass.
Anyway, I still love them, and I just might have to get a pair of subwoofers for the boomy bass I am looking for. I want two (one for each side so I have stereo) and under $500 for both total would be nice. Any suggestions? Do I even need two? I've read that most stuff nowadays isn't mastered with stereo bass, and I listen to mostly indie hip hop from my hometown of KCMO so it's even less likely to have that, I bet.