Originally Posted by AC2011
Hmmm...maybe I need to make a quick trip from NB to Quebec!
Before you do, let me act as a spotter first -- or at least I'll point you to the phone numbers of the 3 local FS. They don't advertise the RC-70s at all on the website now. Last time I checked was this summer. They may be gone now, but if not, there is a chance you could find five RC-70s in Quebec City if you're willing to use a tower as your center speaker. Not a common setup but perfect timbre match. That being said, good speakers are not that hard to find and you may be better with a brand that actually is willing to distribute and sell their speakers in a consistent manner.
I have kind of "settled" on sealed subs after talking a couple of times with Tom. My listening levels are not extreme (nowhere near reference); but as the system is mostly movie & TV, little music, I'm interested in good low extension, rather than max SPL.
I don't want to further confuse you -- on the contrary -- but what I've learned these past few years is that extension and max SPL are in fact linked, as it's exponentially harder to get a sub to play a given SPL level as the frequency goes down, but at the same time, the threshold of human hearing / perception goes way up as the frequency goes down. This means that if your setup can play a flat 90 dB SPL even to single-digit frequencies, well I'm convinced you won't perceive much below 20 Hz. Can you even perceive 10 Hz below 100 dB SPL? I'm not even sure.
The only way to get lots of SPL at very low frequencies (e.g. 10 Hz) is to use a sealed sub as the low-frequency roll-off is much gentler than with a ported or passive radiator or horn sub. This in turn can be picked up by natural vessel (room) gain. But again, to get lots of SPL at subsonic frequencies, you need monster subs and kilowatts of power. While I'm impressed by the XS15se's specs, I don't expect one or even two of them to be authoritative below 20 Hz.
Ported subs have a *huge* SPL advantage around their tuning point. So large ported subs that are tuned below 20 Hz (Large & Low-Tune or LLT) are a very efficient way to generate plenty of ULFs. While my SVS Pluses are not that large compared to some designs, they fit the bill for me: they're incapable of doing anything of interest below 15 Hz but I get tremendous output in the 15-20 Hz region in 16-Hz tuning, which is really fun. So in a sense I sacrificed sub-15 Hz output for lots of 15-20 Hz output and with a limited budget (and space!) that was a good strategy I think.
For example, no sealed SVS sub -- even the Ultra -- can even approach the 16 Hz output from a Plus in 16 Hz tuning (just compare on data-bass.com). Thus saying that you don't want a ported sub in order to get more low-end extension instead of high SPL is a bit misleading. However the sealed subs are typically cheaper, more compact, etc. And it's the only way to reach lower. Dual XS30se are packing quite a punch and may indeed dig pretty low given the right room gain profile.
All of this is why I just can't make any decision! I just know I want something different than the Velodyne I currently have which has lots of SPL, but not much low extension.
Yeah sorry about that, I'm not making your life easier am I? Things were much simpler for us Canadians when there was only SVS in town
Also you must be aware that even if you do buy dual XS30's, it won't be the end of the road, and that each dollar invested in more and more powerful subs have diminishing returns in terms of final effect at the listening position. Replacing the Velodyne (which, depending on the model, might even struggle with 30 Hz) with a single $799 XS15 that can reach 100 dB SPL at 20 Hz will be a great upgrade, and so would going from a single XS15 to dual XS30, but the price step would be much steeper at more than $2000.
So you should set a budget and hard constraints (like available space) and just choose a good sub that fits within those. You can't really go wrong with any PSA or SVS sub anyway.