Help finding a subwoofer

@alanpiga  the PB2000 to me is better musically. It just breathes and has such a presence. Makes sense, the box is huge by comparison, as is the driver. Funny thing is the internal amp in the micro is more powerful. I have read that folks seem to like the SB2000 more for music, reportedly faster and more musical likely due to being sealed as opposed to a ports on the PB.

Couple of variables to me that could be in play is my two rooms are quite a bit different. The basement room has loads of room treatment. Corner foam, stand alone traps and about half the back wall covered in acoustic foam panels. Living room is smaller and has no treatment at all. I think if I could have a bigger sub box in the living room I would have gone with either the PB2000 or the SB2000.

Here's a negative comment about REL subs: I use 3 from the same era, 2 Q150s and a Q108 MK2, and REL will not repair them...no no no. I inquired about this and they stated to me in no uncertain terms...no. There ya go. I still like RELs though and would buy a new one if needed.

 how the input of a subwoofer is able to deal with signals from all amps in a high level input

The sub high level input is high impedance, so only uses voltage and very little current from the power amp. Level control adjusts.

A hundred-fold increase in power is only a tenfold increase in voltage and easily handled with a high resistance input potentiometer. How inaudible the additional wire and circuitry is depends on the power amp, cables and listener.

alanpiga, I'm sure I'm missing something regarding your sub requirements.

I see Cain & Cain offers a reasonably priced sub that seems tailored to their speakers when using a capable amplifier?

Your preamplifier appears to have an extra set of low line level RCA outputs? Are you currently using those outputs for something else?  

Thank you for your post. That Cain and Cain sub offering is years gone. Sadly Mr Terry Cain passed away years ago. Yes, that is a “lovely”. Open if one became available. Or two!!! Thanks again Bayle was the subs model name I thick.