It isn't true but I know what he is trying to say... many "SQ" subs tend to be single 4 ohm(memphis, XLS autosound) where as many "SPL" subs are dual coil(Treo, Digital Designs).
This isn't really a rule, but I would say more of a very loose pattern that you see if you look at a lot of subs and the way people use them. I would say it is because SQ people tend to run a class A or AB 2 channel bridged at 4 ohms in a sealed enclosure, whereas SPL people tend to run class D's or other designs which are stable to high current loads and want the dual coils to serve as an option to wire them to low impedances and use them in ported enclosures.
You CAN'T judge the type of an enclosure that a sub will do well in by the coil though, this has more to do with the moving mechanical parts if anything. I think the pattern has something to do with what people buy...
I was looking a Madisounds web site. I am going to purchase the XXLS 12. On their site they suggested either the sealed or the vented for the DVC version but only a sealed for the SVC. I didn't know if that was intended or just a suggestion but that is where my confusion came from.
My intention is to run a pair in a sealed enclosure. I haven't purchased the sub amp yet so I am trying to decide whether to run a monoblock style amp (class A or AB only) and run them in parrallel to get the load down to 2 ohms on an 8 ohm driver or....
Run a larger 2 channel, wire them independently with DVC drivers in parrallel, positives to positives and negatives to negatives, producing a 4 ohm load on each 8 ohm driver.
Any thoughts as to which is better monoblocks or big 2 channels?