Anybody using the SVS PB1-ISD?

Discussion in 'Speakers' started by Joel()Les, Jan 23, 2004.

  1. Joel()Les

    Joel()Les Agent

    Joined:
    Jan 15, 2004
    Messages:
    48
    Likes Received:
    0
    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?
     
  2. EricN

    EricN Stunt Coordinator

    Joined:
    May 30, 2000
    Messages:
    71
    Likes Received:
    0
    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.
     
  3. Chris A H

    Chris A H Stunt Coordinator

    Joined:
    May 10, 2002
    Messages:
    172
    Likes Received:
    0
    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.
     
  4. chris.y

    chris.y Auditioning

    Joined:
    Aug 8, 2003
    Messages:
    12
    Likes Received:
    0
    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.
     
  5. Joel()Les

    Joel()Les Agent

    Joined:
    Jan 15, 2004
    Messages:
    48
    Likes Received:
    0
    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.
     
  6. chris.y

    chris.y Auditioning

    Joined:
    Aug 8, 2003
    Messages:
    12
    Likes Received:
    0
    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.
     
  7. AxelKro

    AxelKro Stunt Coordinator

    Joined:
    Dec 24, 2003
    Messages:
    102
    Likes Received:
    0
    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...
     
  8. steve nn

    steve nn Cinematographer

    Joined:
    Jan 12, 2002
    Messages:
    2,418
    Likes Received:
    0
    Nice post AxelKro. I don't think I have seen that info before.
     
  9. AxelKro

    AxelKro Stunt Coordinator

    Joined:
    Dec 24, 2003
    Messages:
    102
    Likes Received:
    0
    Hi Steve,

    I took it out of the german HiFi Forum. We have a math. Wizard [​IMG] 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. [​IMG]
     
  10. steve nn

    steve nn Cinematographer

    Joined:
    Jan 12, 2002
    Messages:
    2,418
    Likes Received:
    0
    [​IMG].........[​IMG]
     
  11. Joel()Les

    Joel()Les Agent

    Joined:
    Jan 15, 2004
    Messages:
    48
    Likes Received:
    0
    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.
     
  12. AxelKro

    AxelKro Stunt Coordinator

    Joined:
    Dec 24, 2003
    Messages:
    102
    Likes Received:
    0
    Hi Joel,

    Pi was there [​IMG]

    OK, let me try to translate the full formula [​IMG] 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. [​IMG]

    di = aw *(dw * dw) / ap * (8 * dp)
     
  13. steve nn

    steve nn Cinematographer

    Joined:
    Jan 12, 2002
    Messages:
    2,418
    Likes Received:
    0
    Looks simple enough to me:p)
     

Share This Page