# Cylinder vs. Box



## nova (Apr 30, 2006)

What are the pros and cons? I have really been thinking about a pr. of PC Ultras :devil: but of course I have to wonder if/how much of an upgrade it is over what I have now (RBH 1212-SE). Does it even compare to anything in the SVS box line??? 

My sub is Ok, sounds fine with music and HT,... plenty loud, but really starts to drop off around 30Hz and is about done at 24Hz (wish I'da saved my REW graphs  ) I'll bet a lot is my room, what I'm really missing is feeling the bass. Again probably room 25'x17' and open to the rest of the house.... but still, for the price of my 1212-SE I coulda had a pr. of PC Ultras.

So I'm curious,...

Tom,.. any chance you have evaluated the RBH sub?


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## Sthrndream (Apr 21, 2006)

Hi Nova,

I haven't personally measured that model. I have seen data on it from other sources though. Based on the data I have seen...it is solid >32-35hz and still offers some clean output down to the 25-27hz range. In a large,open room area like yours, my first suggestion would be dual PB12plus/2 subwoofers. This won't cost you much more than the dual PC_Ultras you were considering...and they would have a definite performance advantage over the PC_Ultras. Would you be able to place both subs near one another, or are you planning on separating them(placing them in adjacent corners perhaps?) Also, approx how far from the key seating positions will the subwoofer(s) be?

Tom V.
SVS


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## nova (Apr 30, 2006)

Placement is not really an issue, my wife does not have a problem with speaker size or placement.

Right now the sub is about 14' from my seating position, in a corner. I could place two subs in the same corner, at adjacent corners, just inside the mains on each side, or one in front and one in the back of the room, etc. etc.


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## Sthrndream (Apr 21, 2006)

Hi Nova,

As long as that corner provides reasonably flat response at your key seating positions, I'd start with both subs there. If you went with dual PB12plus/2 subwoofers(in 20hz mode), you can expect strong extension down to the 17-18hz range, with clean output capabilities of 118-124dB with no problem at all. This will be perfect for action oriented DVDs at louder volume levels. And of course, once everything is properly calibrated(and phased) the subwoofers will perform wonderfully with both music and film source material.. Dual PC_Ultras will offer the same extension(also in 20hz mode), but you'll lose 2-4dB of clean output. 

Tom V.
SVS


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## nova (Apr 30, 2006)

Tom Vodhanel said:


> Hi Nova,
> 
> Dual PC_Ultras will offer the same extension(also in 20hz mode), but you'll lose 2-4dB of clean output.
> 
> ...


Why is this? Because of dual driver vs. single in the PC-Ultra's?

Out of pure curiosity, what would happen with dual drivers in a cylinder? Would it be feasable to port it? or would it have to be sealed?


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## Sthrndream (Apr 21, 2006)

Hi Nova,

Yes, 4 drivers with about 450w each versus 2 drivers with about 550w each. That is the primary reason why the Plus/2 will have (on avg) about 3dB more output. Another way of looking at that is it would take three of the Ultras to match a pair of the Plus/2 subs.

We have 2 and 4 driver cylindrical proto types on hand, both ported and sealed. So anything is possible, but none of these are close to being production ready.

Tom V.
SVS


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## Ron Stimpson (Jun 26, 2006)

Nova,

Just wanted to point out we dont' call them FAQ's for nothing, this is a good question, and one we address a bit on the website even:

http://www.svsound.com/questions-faqs.cfm#cylinderorbox

Both form factors have quite a few advantages, with a few cons of course. 

Ron
SVS


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## Blaser (Aug 28, 2006)

Tom Vodhanel said:


> Hi Nova,
> 
> As long as that corner provides reasonably flat response at your key seating positions, I'd start with both subs there. If you went with dual PB12plus/2 subwoofers(in 20hz mode), you can expect strong extension down to the 17-18hz range, with clean output capabilities of 118-124dB with no problem at all. This will be perfect for action oriented DVDs at louder volume levels. And of course, once everything is properly calibrated(and phased) the subwoofers will perform wonderfully with both music and film source material.. Dual PC_Ultras will offer the same extension(also in 20hz mode),* but you'll lose 2-4dB of clean output. *
> Tom V.
> SVS


Hey Tom!

I think that will also depend on the frequency, I wonder if there won't be the same output below 25 Hz:dunno:


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## lienly (Sep 4, 2006)

any updated info of such multi drivers cylinder subs?:hail: curious how can you put many drivers into a tube?



Tom Vodhanel said:


> We have 2 and 4 driver cylindrical proto types on hand, both ported and sealed. So anything is possible, but none of these are close to being production ready.
> 
> Tom V.
> SVS


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