Could someone explain these graphs to me please? SVS Subs

If you dont think 3db is noticeably louder then you may be deaf

Whats your current sub... get two PB12NSD and then put them in different corners of the room. Dont just buy one big sub and expect it to sound great no matter where you sit (it wont)

Doubling cone area and keeping power levels the same gets you 3db

doubling power and doubling cone area gets you 6db

You can read this forum and gather a lot of info, or maybe the DIY forum

My advice is not to buy SVS at all, buy two rythmik FV15HP and you will probably never need to buy a sub again

Displacement is measured in liters

sd (cone area) x xmax x (2/1000)

Good luck getting those parameters from retail subwoofer manufacturers.

Don't forget, the PB12-nsd and ultra were tested by Josh Ricci and the PB12-plus was tested by Paul Apollino. They tested with different equipment at different locations so their results could be different by a couple of db. I would probably just assume the PB12-plus is between the results of the nsd and ultra, measured by Ricci. Whether or not the performance difference is worth it is a personal decision. Remember, while a 3db increase may not seem like a lot, it is not easy to accomplish. Doubling amp power results in a max increase of 3db and an increase of 3db requires twice the cone excursion.

Just because two drivers are the same diameter, does not mean their performance will be anywhere near the same. Just look at the pictures and description on the SVS site of the nsd and plus drivers. The plus driver has a larger motor, voice coil, dual spiders and more excursion. All of that can result in large difference in performance. The ultra driver is not only larger in diameter, but also has a more linear motor, better voice coil and probably more excursion.

-Mike

Getting one big bad subwoofer doesnt do much, it leaves you with a bunch of peaks and nulls in your sub response that sound bad. I used to believe that its better just to have one really good sub than two or more good ones, but once you have two subs you will realize how foolish that sounds.

As i said above, when you add another 12NSD its like adding 6db to those numbers, which is a lot. However, you also get the added benefit of smoothing out peaks and nulls, which is a plus.

These words dont make sense, powerful and loud describe the same thing.. perhaps you mean you want bass that has more extension?

Just because svs has an upgrade policy doesnt necessarily mean you should use it. I think the FV15HP performs better than the 12-plus, so buy that, put it in 1 port mode, be happy with a little more extension, and keep the NSD. problem solved

This really depends on the room and if you want a smoother response across multiple seats. I have a fairly smooth response at the main LP with just a single sub and no room treatments. However, for full disclosure, I am planning on getting a second sub to even out the response throughout the entire room.


Again this is very room and location dependent. See here.

-Mike

Maybe you should call SVS and see what they recommend for what you expect the Ultra will no doubt beat the NSD in every way both extension and output not to mention weight and size of the box if you have the budget I doubt you would regret it after all it is a top notch sub in any book.

Driver size is just one factor. Compare the weights and size of the enclosure which adds to the production cost and shipping cost.

If you look at the testing you maynotice that max output is not the only thing tested. WHile the PB12 is impressive, the PB13 retains its native frequency response much louder. While at some point the PB12 simply stops getting louder below 30 Hz, while higher frequencies goe up with increased input, the PB13 does not compress until 110 dB in the deep bass, which with room gain is likely to let you play at reference without any compression at all.

The Plus and Ultra also use more advanced amplifier electronics than the NSD, and they have variable tuning modes that allow them to descend comfortably to much deeper extension (per AH measurements, in 15Hz mode, the PB13-Ultra can push almost 90dB at 12.5Hz, outdoors). Their drivers are also simply *better* than the NSD, so their sound quality is likely notably better (they produce less harmonic distortion and exhibit substantially less group delay, two easily measured values that directly relate to the quality of a subwoofer's sound). In other words, output isn't everything. If I had money to burn, I'd definitely trade my PC12-NSD up to the PC12-Plus to get the deeper extension, output control features and better driver; I wouldn't be inclined to run it any louder, though.

Moreover, in the links you added to the original post, the PB13-Ultra's numbers in 15Hz mode are being compared to the PB12-Plus' 20Hz mode. The proper comparison between the two subs is when they are in matching modes, 15Hz vs 15Hz, and 20Hz vs 20Hz. Audioholics' PB12-Plus review didn't include any mode other than 20Hz mode, so here's the fairer comparison:

PB12-Plus in 20Hz mode (you want to see the "RMS @ 2 meter" column)

PB13-Ultra in 20Hz mode

In the challenging places of the spectrum (everywhere under 40Hz) the Ultra is at least 3dB louder. Yes, that's a highly audible and tangible difference at these output levels.

It's also worth noting, as others have, that the enclosure itself and larger driver assembly add significantly to the costs of both manufacture and shipment. Personally, I prefer the cylinder versions of all the SVSound subs--comparing price to performance, in my opinion they offer a better value, and I can move them without having to radio for backup.

You also need to keep in mind that the above measurements are done outdoords with no room gain factored. It is possible to get another 6db based on room gain alone, but as others mentioned, it comes down to your room and what you are trying to do.

No one has asked this yet: how big is your room? The room can affect the in-room response more than anything, so if your room is gigantic I could see why you'd be wanting more.

My understanding is that it's hard to get both of those at the same time. Co-location of two identical subs can yield up to +6dB in a room, but it doesn't do anything to solve the peaks-and-nulls problem; distribution across a room can do a lot to solve the peaks-and-nulls problem, but then the maximum output increase tends more toward +3dB.

Something to keep in mind is that the dB scale is logarithmic in nature, not linear. If you purchase a second PB12-NSD and stack it on top of your first, theoretically you'll yield an additional 6dB of output. If you purchase an additional two more PB12-NSDs on top of that, you'll yield another 6dB of output.

Consequently, if you purchase a PB13U, in 20Hz tune you'll get ~8dB more output on average from 20Hz to 125Hz than you would with your NSD. That is about 1dB less than if you had a stack of 3 PB12-NSDs.

If you consider things from that perspective, the pricing starts to make a lot of sense. The PB13U is a bit shy of triple the price of three PB12NSDs, and a bit shy of triple the output as well. As an added bonus, you get a few added features (tuning options, more advanced amplifier) and a nicer cabinet. Not a bad deal all things considered.

Care to try out your theory?

How about one of my captivators against two of your rythmiks?

You pick optimal placement for your pair and I just drop one cap in one of your two places for the comparison.


I would typically agree with you that 2 subs are usually better than 1, but if that 1 is in such a different class - the story changes dramatically.

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Because I can't find an equivalent excursion video for the caps, and I'm not sure I want to do this to my own drivers - - -
Check out the excursion video linked here on the Elemental Designs 13av2 driver
http://vimeo.com/6819518
That ED driver is is rated for 28.5mm xmax each way
The Captivator driver is rated for 30mm xmax each way

With that 30mm of xmax you can do things like this -


YET, you can still keep excellent sound quality at typical and even crazy listening levels as evidenced by the fact the Caps place at or near the top in listening auditions at all the subwoofer meets.

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The other thing to keep in mind is that every 3dB is 50% more spl, every 6dB is a doubling of spl. So since the scale is doubling - as you approach the thresholds of human 'pain' levels 50% more spl is a WHOLE lot more noticeable.

This scaling factor is why if a woman screams at 125dB, two women don't scream at 250dB (250dB is the spl of an atomic bomb - - http://www.makeitlouder.com/Decibel%20Level%20Chart.txt) -- rather two women together might hit ~128 dB - unless they are co-located - but that kind of topic belongs to another forum.


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As to why the BIC F12 didn't compete with the SVS -- I'd wager it got close in SPL levels, but that SPL level's high water mark on the BIC F12 is not flat in regards to frequency response. My friend has a couple BIC V1220 subs (pretty equivalent to the BIC F12) and they hit 121dB in his room peaks, but that 121dB peak sounds a lot different than my Captivator pair at 121dB, because the BIC's fall off hard at about 33hz and produce basically nothing at 20hz. The 50hz - 70hz sound that the BIC's produce in abundance, is the type of bass you feel in your body, chest etc. The 15-25hz bass is the type of bass you feel in your chair, your house, your walls, your floor, and the eerie sensation that makes you involuntarily grin ear to ear.

I actually found the opposite to be true for me. I preferred the one big bad sub to two lesser ones. It was actually a noticeable difference. I can always add a second big bad sub down the road

That's because its frequency response curve is far from flat. Check out the BIC F12's big brother, the PL-200 in this table. See how it's 14db higher at 50hz from 25hz? So at a given volume setting on your receiver, the loudness for the BIC F12 will be coming from the upper bass range, and the lower bass range has relatively low output in comparison--which is where the room shaking effects are coming from. And Audyssey can't adjust for that much difference in response to flatten the curve. Whereas your SVS (scroll down the table) will potentially put out much more solidly across the frequency range.

My advice would be to call SVS and discuss your room and needs as well. If you have the budget, I would say get the Ultra and don't look back.

That is the philosophy that I am following. I bought the best sub that my budget allowed and I will be adding another equivalent sub when my budget again allows me to do so. I have no complaints about the sound I am getting from the one sub now and I'm sure that adding another will make things even better.

I am considering the HSU Mid bass module with nearfield placement. That combined with the VTF-15H seem like a really powerful combo of my large room.

There's output (volume) and there's extension (depth/rumble). Your PB12-NSD is no slouch in either department, but the PB13U offers more of both. Of course keep in mind, while the PB13U digs deeper than a PB12-NSD, not all source material calls for extension down to 15Hz, especially when it comes to music.

Got any graphs of one captivator running? Feel free to EQ it too, though the OP probably isnt going to go that far. Captivator is one of the few subs id feel safe EQing because i trust the amp to have gobs of power (although its already DSPed... which leads me to believe i might be double boosting). When you boost your nulls by +3db the amp better have the headroom, because if you push it to reference and the amp starts clipping you just ruined the movie for yourself.

I dont have any rythmiks, i am a DIY guy. For $2500 (the cost of ONE captivator) i could have two RE XXX18, an LG clone amp, and have far more extension than two captivators could ever hope to have (the RE XXX almost doubles your xmax, and id have two of them), plus far smoother room response.

Do you have a picture of your bass FR?

Of course a bigger sub will probably provide more extension and it will provide more output, the question is how many nulls/peaks do you have unaddressed in your room. I dont like having one 40hz explosion go off with a whimper because its in a null, and another 60hz one rattle all my doors because its in a peak, it leads to an inconsistent bass experience.

I agree with ack_bk: Call SVS and discuss your situation with them. A second NSD will certainly give you more headroom and rumble (more envelopment too), but the PB12-PLUS or PB13-ULTRA will most definitely give you that extra punch and shaking that you're looking for. The Rythmik FV15HP is also something you should consider.