Help choosing a subwoofer - BK P12/XXLS400/XTZ 12.17


Established Member
So i'm currently running a battered Q Acoustics 2070si (twin 6 inch cone) as my only subwoofer, alongside a Zensor 1/Vokal LCR (no surrounds yet).

I've had the 2070si as a stopgap until I could acquire a bigger and better subwoofer, so the question is, which of the following should be my best choice for price/performance and will they be a significant upgrade over the 2070si? (which itself should be £270 usually)

BK Elec P12-300SB DF or FF - £370
BK Elec XXLS400 DF or FF - £370 (B-grade, tiny scratch, i'm fine with this)
XTZ 12.17 - £599 (could stretch to this at the very top end but needs to be a big enough upgrade to justify the money)

The room is a decent size (4.2m x 6.5m) and the HT setup is clustered at one end. The subwoofer will be going between the two sofas which are at an angle to each other - about 2ft from back wall.

What do I like? I like good decent, clear bass. Not really one to rattle the windows with my listening but I do like it to extend deep without overwhelming the main speakers. Probably about 90% Home theatre and 10% music. [The 2070si will be going in a cabinet in the music room and acting as a music complement subwoofer, but until then would it be silly to run both?]

Last question - the floor is suspended wooden floor but is solid despite this. Should I be going FF?


Distinguished Member
All those should be quite nice upgrade from the "mid-bass module". ;) I remember reading ages ago that some guys upgraded from 2000 serie Q-Acoustics sub to XXL400 and were more than happy.

XTZ has advantage with the ported design, meaning it can go lower and play louder. It also has superb tweaking options. For 90% HT usage it would be on my list with SVS PB1000 / BK Monolith Plus with that budget.

You might find this thread intresting; XTZ 12.17 vs XXLS400

BK Monolith / Plus is also great option -+500£. But as you didn`t mention it, i assume it`s too big.. For your room it`s definitely NOT too big.

Just remember you can always dial down the bigger subwoofer, but to get more performance from something smaller/less capable isn`t happening. You have quite largish room so it`s hard to say would you be satisfied with the BK sealed sub(s). XTZ subs can be demoed at Jag`s place, for the BK you would have to find member near your area who might let you hear it. It won`t be same as your home, but would give you some kind of idea how they perform.

"The subwoofer will be going between the two sofas which are at an angle to each other - about 2ft from back wall."

This could be hit or miss. Usually not advised to put subwoofer where it looks best, rather where it sounds best. And that means trying it in couple places..


Established Member
Thanks. It's an awkward choice. If I wanted room-shaking and body slam then the 12.17 would be a no brainer but I think(?) my requirements for decent, good quality bass would be satisfied by a 12'' sealed - the XXLS400. But I can't shake the worry I might miss something or be better served by a bigger one! ;)

I could stretch to the 12.17 but it would be a stretch, my funds were originally intended for a P12-S300 but there's a few B-grade XXLS400's going for the same price.

The Monolith is simply too big cabinet wise for the 4 placement options i've got.

RE: Placement, yeah i know. I have about 4 possible room placements which the XXLS400 would fit in potentially, that's just first choice and convenient power etc. Two other possible end-table options and of course it could just go slightly behind/left of screen where current one is - seems to give a definite peak at MLP.

Given that it's basically alongside the middle of back wall of the MLP, I'm fairly confident it'll place fine there.

Reading the reviews of the XTZ 12.17 you linked to it does sound like it could rock the room a bit more but the side-by-side was that there was actually little difference and the BK XXLS400 won out on quality. The extra frequency response appears to be minimal at best in real life testing.

Think my mind is made up - now to convince the guys at BK to throw in some superspikes on their B-Grade!


Established Member
Happy to say I received my XXLS400 the other week. If it is a B-Grade unit, I can't find the 'blemish'. There is one spot where the cabinet walls are a teensy bit misaligned but i'm unsure how much that's normal, and it's covered by the grille anyway. Delivery and SuperSpikes thrown in as well.

Very happy. Gain about 40% and it's plenty. Enough to vibrate my floor and really give a sense of deeper bass sections being 'real'.

Setup was easy and quick, plug in, bypass filter, gain to 40% and already it was about right. Yamaha amp trimmed to +1dB which is fine. Now for the next few weeks of tinkering.

Only problem is the back is exposed to my toddler. He likes 'twiddling' the knobs :confused:

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