Coming, to a theater near you. (1 Viewer)

[Chris James]

Ron, I see you are calling it the PB1-ISD. My assumption is that it stands for Powered Box 1 - Improved Standard Driver. Nice name, but.....
I figured you guys would go for something more like PBi, then maybe the PB+ using the Plus driver later on. Much easier to say (and type), and follows along with the PCi and PC+ abbreviations. I don't know if there are going to be any differently tuned box models, but PBi-16/PBi-20/PBi-25 does sound good. I just think saying "Yeah, I bought a PBi-16 from SVS!" sounds better than "Yeah, I bought a PB1-ISD from SVS!" Just say those two sentences out loud.
Now, as far as the "debate" on port noise, etc on the B4-Plus (which I prefer the name PB4+ hehe). I am sure Tom is WELL aware how much porting is needed.
From Seth:

I'm sure that you've tested it a lot, but the bottom line is that your air velocities in the ports will be too high at high volumes. There will very likely be audible port noise.

You can tell by a few pictures exactly how much porting was done to this box? Ron already laughed at the "underported" comment. And I am sure Tom V. knows as much or more about porting subwoofers than anyone else here. Good job Ron and Tom! That thing looks like a beast! Guess I'll slink back to my lowly 16-46PCi :frowning:

 

[BrianKR]

I think it would have been nice if there were more than 1 member on the HTF to get a beta. It would offer more variety as far as types of set ups go. Also you KNOW that there will be a lot of questions for him/her. He/she could easily get overwhelmed.

Especially if that person is not audiophile and just a audio enthusiast like myself ;^)

 

[Aaron H]

How long before we see a more "consumer" oriented version of this box sub? I got my 25-31PC+ last week, and the wife wasn't too happy. I think she'll be alright, but a cube sub would definitely be better for my situation.

Aaron

 

[Seth_L]

You can tell by a few pictures exactly how much porting was done to this box? Ron already laughed at the "underported" comment. And I am sure Tom V. knows as much or more about porting subwoofers than anyone else here.

Sure... There are 4 4" ports. That only presents 324cm^2 of port mouth opening. The enclosure is about 2' cube. Max port length should be about 20" (to allow the ends to breathe). From the placement of the ports (as seen in the pictures) there doesn't allow room to have elbows for the ports (increasing their length). There's nothing special about the design. Ports are ports. The speakers in the box have pretty much nothing to do with how the ports behave. The only things that matters are the nubmers of ports, the size of the ports, their length, and the box volume. I'm sorry if you don't think we can make good estimates of that information, from the picture, but we can. Bottom line is that 4 4" ports that are 20" long will only tune that box to about 29Hz and the air velocities are too high with 5kW on that sub. That will yeild chuffing and port compression. Whether or not you can hear if over all the rattles and buzzing that will be occuring in your room. Who knows.

Seth

 

[ErichH]

Perhaps we get a discount from the Army Core Of Engineers - They show up and secure the room before you insert your DVD.

Dear SV Guys....Keep Goin'

Eric

 

[Chris James]

The box is longer than 24". That much is clear from the pictures. The face with the ports and 12" driver look like they could be roughly 24", but you can easily tell the box is longer. I'd be willing to bet a lot of money that the ports are longer than 20".

 

[james e m]

Would there be any reason to need dual B4-Plus'? I have no real knowledge about subwoofers, would this sub be equivalent to 4 other subs? What's the purpose of having 4 drivers?
James

 

[Jason_S]

Ron or Tom,
How do you recommend someone place this uber subwoofer in a listening room? (Not only where, but also which side of the box faces out/toward the listening position.)
Also, who makes "reasonably priced" amplifiers that approach the full 5kW?

 

[Andrus_R]

Why you don't you put a blanket over it and lie down on it. It seems big enough haha.

 

[Dustin B]

I've had a few conversations with Tom about this thing.
It's 25x25x31. The drivers are in a push pull config (like M&K). It's not a dipole, all the drivers push in and out at the same time. The two inner ones are out of phase with the outer ones (at least that's my understanding of a push pull design). The tuning points from open to all but one closed are 25hz, 20hz, 14hz and 8hz. The walls range form 1" to 2" thick. The pedistal doesn't add any volume to the box. Over all wired for a 4ohm load.
Tom plans to put 4 of them with a 1000W to each box in his room (2 channels of a Crown Macro Reference with the 4 in parallel pairs for 2ohm loads). Figures he might get into the 150dB range in room with this setup (I assume around 25hz, but he wasn't specific on the frequency on this point; ground plan 2m he figures high 130dB).
As for if it's underported or if it can really take that kind of power, I'll leave that for Tom. Sorry if I over stepped here Tom. But the pics are up so the cats out of the bag. Was fun knowing what it was while people were speculating about quad sealed 15" subs
And no I'm not the lucky bastard who gets to beta test it :frowning:

 

[Chris Tsutsui]

Well I guessed the 4 open tuning point to be 24hz which isn't far off.
My mistake was wording that the drivers all push in and out at the same time thus it being a dipole. I forgot how the inner drivers are flipped.
If you think about it, with one enclosure, how would isobaric take advantage of the ports? We just didn't know if the box was divided into different compartments or how the porting went. Thanks for info Dustin, I now know more about the sub i'm beta testing. (j/k I wish)
I just got an idea, what if a manufacturer built a driver that has two built together that share the same magnet. Then it can only be used in a way the SVS has them on the inside. Heh, that would be weird but it might have some advantages.
Has SVS thought about selling drivers they develop to be cost/performance competitive in the DIY market? Maybe they could be designed differently than the ones they use so as not to affect commercial sub sales as much.

 

[Michael R Price]

Thanks for the info Dustin. Regardless, I won't be able to afford it. I am very curious to see Tom's measurements.

 

[Dustin B]

I just got an idea, what if a manufacturer built a driver that has two built together that share the same magnet. Then it can only be used in a way the SVS has them on the inside. Heh, that would be weird but it might have some advantages.

That would be a dipole Chris. Here's an animation of a push pull config that might make it clearer.
http://www.hometheaterhifi.com/volume_3_1/mkmx1.html
This arrangment is supposed to cancel even order something other distortion. I'm sure Tom can explain more.

 

[Tom Vodhanel]

Hi Guys,
Really it's nothing but a Blown BBC(Big block chevy) in a world busy putting a chrome air cleaner on their 4 cylinder. Just a big ported enclosure.
Could it be considered *under ported*? Absolutely, there are always design compromises that must be considered.The question here should be...at what output level will the ports begin to *audibly* compress and how will that relate to what the rest of the room will be doing at those levels?(walls and floor flex for example ) I'm not sure how it will look on *sims*---I've been experimenting with this design for over a year now and can't remember running a simulation on it yet. We've just been so damn busy actually building and rebuilding about 6-8 variations on this and then spending hours and hours measuring each---how *old school* of us
I think our Ultra design has been verified to offer good output? (see the independent objective data gathered by John Johnson and Brian Weatherhead for details).In ground plane testing using a 1500w amp(Crown K1 bridged) here is how the B4 compared to a single Ultra/500w.(running max output tests at each 1/3 octave using a 10% thd limit)
FYI ~We use Soundtechnology V4.32 with an assortment of LinearX and AudioControl mics for testing. We have 1/96th octave resolution and calibrated mics capable of 176dB readings.
Ultra set to 20hz/B4 with all ports open
20-80hz avg ~ B4 was +9.9dB
25-63hz avg ~ B4 was +10.4dB
Ultra set to 20hz/B4 with two ports blocked
20-80hz avg ~ B4 was +10.4dB
25-63hz avg ~ B4 was +9.6dB
Ultra set to 16hz/B4 with two ports blocked
16hz B4 + 6.4dB
20hz B4 + 8.0dB
Please note---most of the B4 output readings were limited by the amp. While the Ultra would max out at 10% thd at just about every frequency before the amp(half a S1000 gave out)...the B4 would routinely show

 

[Cam S]

Good friggin lord, that is a crazy ass sub!! 5000 watts, that is insane!!! Now, if only i had the cash.....

 

[Andrus_R]

Cash then what? Put'em in your basement insane HT asslyum?
Since this "thing" has the price tag to match it's size i'd say it's more suited for Pro use then home HT use for "most" people.
Oh i can almost hear it now, it's for elite few with $$$ and it's for the enthusiast who crave the ultimate.
...*snicker*
Well at least it's still cheaper than krell ref sub.

Nice going SVS, from cheap bazookas to motel vibrating bed lol. Ok i'd better hide before TV calls my ISP and threatens to kick my butt.

Comments like that are not tolerated on HTF.... Please refrain from personal attacks, or you will not be permitted to post on HTF any further... Thank You, Steve Simon

 

[ArthurM]

Um EEEGGGAAAAADDDZZZ, I just have a phew question's on this sub.

1. What would the purpose of this sub be. Maybe as a dynamite substitute. Just plug it in play a movie like Jurassic Park and wha La no more glass/pictures or fillings.

2. I have not bought my SVS yet simply because well I am saving up. If I wait to long will I miss out on the 549.99 Pci 25-31???


3. By Mid March I will have enough money to purchase my SVS sub. But it seem's as though my Decision has gotten allot tougher.
Square or Round. I still like round.

Thanks, Art.

 

[Chris Tsutsui]

As for this Box4, it's like you're putting a jet engine in your room.
130db of bass, (without much distortion) isn't going to rip ppls heads off. The sub will still be calibrated to HT levels and simply provide some headroom for the LFE tracks.
For me it's easy and comfortable in a car when the bass is at 130db. However, throw in a cheap sub and crank it to just 110 and the distortion can really hurt the ears.
Could you imagine how much harder it would be to try and linearly increase the output of the Box4 by just 3db?
BTW, if you think 5 kilowatts is impressive, how about a subwoofer that handles 7200 watts RMS with an amazing 109.5db sensitivity. Check out the Avantgarde Basshorn. The drawbacks is it takes the place of your entertainment center, weighs a half ton, and cost's a tad more.

 

[Chris Tsutsui]

lol, I just saw SVS-Ron's link to that animation.

So if that cylinder with horns represents say an Ultra, and the Box4 does so much better, shouldn't that change to a box stomping on the cylinder?

 

[Andrus_R]

Well Gee...
Talk about 'different strokes for different people'. I guess whatever floats your boat