Anybody using the SVS PB1-ISD? (1 Viewer)

[Joel()Les]

I've been looking at subs and really like the concept of the SVS cylinders, but a sub that was no higher than 24" ( 22" or less is even better) would work much better in the room decor (i.e. wife factor). So is anybody using them or had an opportunity to listen to one? Does it live up to the 25-31 PCi?

 

[EricN]

I had a 16-46PCi (I have since upgraded it to a PB2+) and I have the PB1-ISD. The PB1 is a terrific bang for the buck. Other than the super lows that the 16-46 can do (Haunting DTS, Iron Giant, etc) it gives everything you could want. Plenty of "Scare the neighbors" power. Very clean music inegration with my DefTech's as well. I am very satisfied with the PB1-ISD.

 

[Chris A H]

I have a PB1-ISD and just love it. Enough bass to shake just about everything in the room on HT, and clean for music as well. Very impressed.

I have not heard the 25-31 PCi but the SVS website FAQ section talks about the PB1-ISD and the 25-31 PCi as being "virtually identical in performance." They should know. See the full box vs. cylinder discussion here.

 

[chris.y]

I bought a PB1-ISD last summer. The performance is really solid. It's tuned to 22Hz and goes deep enough for me (and way too deep for my wife - we had a picture fall off its hook during the Moria scene in LoTR).

One thought on sub size -- it's pretty big. So, even though it isn't as tall as the cylinder sub, it's bigger than our end tables. I put it in the back corner with a giant stuffed bear on it and no one seems to notice.

When I first joined this forum, I thought there was some sort of conspiracy about SVS with all the good reviews. Now that I've owned one for 6 months, count me part of the conspiracy.

 

[Joel()Les]

Chris: I noticed that is pretty deep and the port is rear facing. That raises a good question. How much clearance from the wall does it need in the back. I think it fits nicely where I plan to put it with a few inches of clearance.

 

[chris.y]

Joel, I've got the side with the port about 6.5" from the wall. I moved the sub around a little in the corner to see if it improved the sound but the characteristics don't change much. I think that the placement in the corner itself is probably the most important. Hope that helps.

 

[AxelKro]

Hi,

the distance to the wall, where the ports are facing to, can be calculated by the size of the cylindrical port space between the Sub and the wall, which should not be smaller than the total area of the woofers. Otherwise, the airflow may be hindered to exit freely.
The following formula can be used to get an idea:

di = aw *(dw * dw) / ap * (8 * dp)

di = distance to wall
aw = amount of woofers (same size)
dw = diameter of woofers (eg. 12 = 12")
ap = amount of ports (same size)
dp = diameter of ports

Examples:

SVS, PB1+ with one 12" Woofer and 3* 3" Ports
di = 1 * (12" * 12") / 3 * (8 * 3") = 2" min. clearance required.

SVS, PB2+ with two 12" Woofers and 3* 4" Ports
di = 2 * (12" * 12") / 3 * (8 * 4") = 3" min. clearance required.

SVS, PB2+ with two 12" Woofers and 2* 4" Ports (one port blocked)
di = 2 * (12" * 12") / 2 * (8 * 4") = 4,5" min. clearance required.


Hope this helps...

 

[steve nn]

Nice post AxelKro. I don't think I have seen that info before.

 

[AxelKro]

Hi Steve,

I took it out of the german HiFi Forum. We have a math. Wizard there, who does most of the calculations and KnowHow postings on speakers.
I just translated the concluding formula for this forum.

I'll send him your regards.

 

[steve nn]

.........

 

[Joel()Les]

From SVS's website:


The base model (ISD) is a single port design. Using SVS's 6" performance benchmark, I get 144 / (8 * 6) = 144 / 48 = 3".
Using the actual 4" internal port size = 144/(8*4) = 4.5"

Interesting to note that the formula does not require the use of either Pi or squaring to account for area even though the port is similar to a pipe.

 

[AxelKro]

Hi Joel,

Pi was there

OK, let me try to translate the full formula Don't shoot the messenger, I'm german !!

Port Diameter= dp
Cylinder surface = cs
Distance (to be found) = di

First formula for the Cylinder/Port surface:
cs = 2 * Pi * dp * di

It is assumed that this surface shall not be less the surface of the used woofer.
It's diameter = dw, it's surface = sw.

The surface for the given woofer is calculated to:
sw = Pi * dw/2 * dw/2

If we equate both formula to each other it looks like:
2 * Pi * dp * di = Pi * dw/2 * dw/2

This formula resolves to "di" as follows:
di = (dw * dw) / 8 * dp

At last we have to add the multipliers for amount of woofers and ports. e voila.

di = aw *(dw * dw) / ap * (8 * dp)

 

[steve nn]

Looks simple enough to me:p)