Ive seen numerous people post about SVS, but I have never heard them in person. I guess Im just trying to wrap my head around that $2000 price tag.
I guess what Im asking, Is the SVS subs really leaps and bounds above other ID sub companies? Epik, eD, Rythmik etc..
I guess what it boils down to is, how important are infrasonics?
It's so easy to run out of headroom below 25hz.
If you go sealed, your determinants of output are cone surface area and LINEAR cone excursion, and getting to full excursion requires either high low end efficiency (difficult in a box). But anyone interested in sub 10hz performance has to make that tradeof there.
If you go vented, yes you can tune low at the expense of content below that tuning. Lots of vented subs are tuned in that pretty ~15hz region that hits a good dollar-to-performance ratio. You think, "I'm getting bass down to 15hz" and leave it at that. But it's not as easy as that. If a 12" driver is vented and flat down to such a low frequency, you just lost a TON of efficiency. It takes high mass to gain efficiency down low. So you need ""WATTS"" and you trade away upper bass impact. Else, you end up with a sloping response like the HSU VTF-15. Now in some rooms a sloping response can be desirable because of room gain, but in other rooms the room doesn't help you much and all and pressurizing it gets EXPENSIVE.
...And you STILL need excursion capability. A vent DOES reduce excursion demands near the tuning point, but if you're tuned low (IE 15hz) you're asking the driver to work hard above the tuning point (IE 21hz).
...and vents aren't magical. The more you ask out of the vent, the more air you need to push through it. If the vent is too small, at some point it becomes a limiting factor in output because deep bass needs the vent to move a LOT of air. What you end up with is just vent noises instead of increased output - a DSP signal processing sub might prevent you from hearing those noises though. If you make the vent surface area larger, getting the same tuning point means a longer vent - where you bring a quarter wave resonance of the vent tube closer and closer into the operating zone of the subwoofer, and you don't want that in its passband or really even under 150hz. So you also need a driver that tunes low easily. This comes back to the driver design and the tradeoffs involved with it.
If you look at these measurements of the Funkywaves 12.x subwoofer
Funky Waves FW 12.X Subwoofer Review Measurements and Analysis — Reviews and News from Audioholics
you'll see that even with a heavy 12"
long throw driver fed 2000+ watts, it barely hits the 116db @ 1m @ 20hz mark. This for a 12" driver is
fantastic performance and I doubt there's many other 12" subs that can match it. Even the PB12+ discussed in this thread, is excursion limited below 32hz:
SVS PB12-Plus DSP Subwoofer Measurements and Analysis — Reviews and News from Audioholics
Now movie reference levels can ask a sub to produce
115db peaks at the seating position(and that's for the few of us who DON'T run our subs hot). And discussed above, was only subs that barely get to that 20hz mark with good output. The next 5hz are what the PB13Ultra will get you.
SVS PB13-Ultra Subwoofer Measurements and Analysis — Reviews and News from Audioholics
... Just because a sub
claims 15hz performance (and all of them always do), doesn't mean it can do it with the SPLs necessary to even perceive the frequency meaningfully. There's still lots of limits, whether you perceive them or not. The Epik Empire, for example, claims
Frequency response : 20-300 Hz +/-3.5 dB anechoic
True 15 Hz or lower in-room extension
Yet it measures:
Are they lying!? No! But they're not being entirely open and transparent either.
So is the PB13U worth what it costs? Every cent of it. Above 30hz, I think there's lots of subs that are just as good. But below 30hz, the ULTRA low frequency transducers are separated from the also-rans - even if you subjectively think your sub goes really deep... have you measured it?
...if you really want the ultimate system, you need to accept the need for
-no resonant alignments, because they don't have anything meaningful below their tuning. They are essentially dipole with the vent or passive radiator canceling the output of the driver which is essentially unloaded from any box loading. So they can't pressurize a room below their tuning frequency.
- no limiting. If your drivers are coming close to their limits on any source content, the only solution is more subwoofers.
- lots of surface area. at least 15" drivers... more likely 21" or 18" drivers. And they need LONG, LINEAR THROW. Displacement is the name of the game. Since there's no vent, transmission line, or passive radiator, you need a TON of displacement. Especially the lower you go in frequency.
- A LOT of power too, though a driver optimized for an infinite baffle can often work great. Remember, the rule of Small, Loud, Low = Pick 2 - so if you want loud and low, a "big box" can get you some real improvements in low end efficiency.
- A small, closed up room really helps, because of pressure vessel gain. If you've got a bomb shelter, you can save a lot of money trying to get an ultimate HT. If you've got a large, open room, pressurizing it gets expensive VERY quickly.
