SVS PB12-Ultra/2 or 2 PC-Ultras?

Discussion in 'Speakers' started by dave/r, Feb 8, 2005.

  1. dave/r

    dave/r Auditioning

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    Hi, I am debating buying one of the above.

    My system is 2.1 at this point and will be mostly used for music, (but of course with movies too) and none of the rooms it will be used in will be massive.

    I have a penchant for deep bass and play a huge range of music, from classical to pop, rock and lots of rap and d'n'b too, which has loud, low, sustained bass notes.

    How do these two sub options differ in performance?

    I know the PC ultras will go lower, but will the PB12 be low enough? Does either have more port noise than the other?

    The tubes are more managable to move about, but need to be co-located to deliver their best performance which negates their lower profile. The box is big and weighs a ton, but its cheaper...

    thanks for any advice!
     
  2. Axu R

    Axu R Agent

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    Even PB10 goes low enough! [​IMG]
     
  3. Ilkka R

    Ilkka R Second Unit

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    The lowest bass in those songs is propably around 25-30hz. ANY svs will play them easily.

    If you don't believe, give me the name of the killer song and I will graph it for you.
     
  4. Michael Brand

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    I would go for the Ultra(s). I recently tuned my dual SVS PC+ 20-39 cylinders to 16 hz from the stock 20 hz tune, and noticed a definite improvement in the way they sound, both with music and movies. It just seems to be a tighter, cleaner sound. You will definitely like the lower bass performance of the Ultra with the type of music you listen to.

    My twin cylinders are not co-located, and sound great. This can be a very hotly debated topic, but here's my take. You will get more SPL from co-located subs, and they may be easier to equalize to a flat response. However, non-co-located subs that are properly set up can really even out the response in your WHOLE room, at all seating areas. If you have enough head room, I think it's the way to go. Here is some really good info from the Rives Audio site.


    Subwoofer placement and number of subwoofers
    This can be the most difficult speaker to place. There are a variety of reasons for this, but in general, bass frequencies are most affected by their placement in the room. First let's examine placement with one subwoofer. This is actually the most difficult. Subwoofers can either be placed in corners, where they have the benefit of sound reinforcement from adjacent walls. This means less amplification is required and less distortion on the sound the woofer is producing. However, this comes at a price. While many subscribe to the thought that bass is omni directional, a woofer placed in one corner can usually be detected as being in THAT corner. Omni-directional does not necessarily mean it can not be detected as a sound source. The other expense is that corner placement excites room modes and generally delivers less than a flat frequency response.

    When we calculate room response curves theoretically, we do it to find out how flat a response we can achieve. This usually yields a subwoofer placement that is slightly off center in the room and fairly far out into the room. This gives us a good idea of how flat we are able to achieve, but inevitably this is not the best overall sound for the subwoofer. It is for this reason that we do not even specify subwoofer placement, rather we give a location where we found the flattest frequency response.

    There really are two potential locations, near center and near the rear wall (within 1/8 of a wavelength of highest frequency the subwoofer is set to produce*), or in a corner and within 1/8 of a wavelength of that corner. We recommend that you try both of these locations. If you can not distinctly detect the subwoofer when it is in the corner, then this is a good place for it. Otherwise, move it to the center.

    If you have two subwoofers, corner placement behind the main speakers is almost always the best placement. These should be within 1/8 of a wavelength to the corner they are placed in. If you can afford a second matching subwoofer, this is generally preferred to a single more expensive subwoofer.

    Getting the subwoofer in phase can be a little tricky for a novice. The best way is to use a test tone at the crossover frequency of the subwoofer. Play this tone and adjust the phase so that the tone is the loudest at the listening position. Using an SPL meter can be a great help here. When it is at the loudest the subwoofer is in phase.

    * Note: 1/8 of a wavelength (in feet) = 1130/wavelength * 1/8

    Thus for a 80 Hz wavelength = 1 foot 9 inches

    Author: Richard Rives Bird of Rives Audio

    Resources and education in Acoustics: www.rivesaudio.com/educate

    Rives Audio website: www.rivesaudio.com

    Contact Rives Audio: info@rivesaudio.com or 800-959-6553
     
  5. dave/r

    dave/r Auditioning

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    Hi Ilkka, can you graph a couple of tunes for me in any case? I am not skeptical, just interested.

    DMX- My Life (I think the bass in this goes to about 28hz, but that's judged be ear using a test CD)

    Gladiator OST- Now We Are Free

    Wyclef Jean- Apocalypse and Gone Til November

    Dillinja- The Box (D'n'B- not extremely deep, but very bass-potent)

    Smith + Mighty- Seeds


    You don't need to plot all of them of course. The 1st 2 would be particularly helpful, because I use them as reference tracks when listening to subs. Cheers!
     
  6. KeithY

    KeithY Stunt Coordinator

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    For music I'd go with the ultra.

    That Gladiator track sounds awesome on my ultra/2.

    I've had the plus/2 and like music much more with the ultra.
     
  7. dave/r

    dave/r Auditioning

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    that's reassuring keith, as music is really my bag. I'm already set on something with the ultra driver in it actually, just deciding between the PB12-ultra/2 box or a pair of pc-ultras.
    decisions decisions!
     
  8. mikeEB

    mikeEB Auditioning

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    I believe that the 2 PC-Ultras will have an advantage over the PB12-Ultra/2 due to internal volume and port area(if co-located). If I were you I would start out with one PC-Ultra and see how you like it. If you feel the need for more.....get the second one. I was in the same boat as you and after a quick email to the guys at SVS have decided to go with the 2 PC-Ultras. My single PCU is incredible in a medium sized room with music and just plain scary with movies. Hope that helps.

    M i k e
     
  9. Ilkka R

    Ilkka R Second Unit

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    Time begins from the bottom. 0min-1min graphs unless other mentioned.


    DMX- My Life:
    [​IMG]

    Gladiator OST- Now We Are Free: (1min-2min)
    [​IMG]

    Wyclef Jean - Apocalypse:
    [​IMG]

    Wyclef Jean - Gone Til November: (30s-1min30s)
    [​IMG]

    Dillinja - The Box: (30s-1min30s)
    [​IMG]

    Smith & Mighty - Seeds:
    [​IMG]
     
  10. dave/r

    dave/r Auditioning

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    Yeah, I've been thinking that myself Mike. The ultras have a particular advantage below 25hz, and I'll be able to move them by myself. More money though!
    Perhaps I'll do as you suggest, buy one get the other. Are you running just the one PC-U at the moment or do you have 2 now?

    Whoa, Ilkka, the graphs are amazing! How do you make them, and how did you find all the songs!?
     
  11. mikeEB

    mikeEB Auditioning

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    Right now I just have one PC-Ultra running with a 20-39PCi. I started with the PCi and loved it......but after all of the reviews about the Ultra driver.....I just had to get "Ultrafied".
    There is definately a sonic and power diffence that can be heard and felt between the two. My wife is in the USAF and we are heading to Germany next month. Once we get settled in there and see what size rooms we have I'll probably get the second Ultra if needed. I personally like the way the cylinders look and they are very easy to move. Two (or more!!!) PC-Ultras is my goal when we finally settle down somewhere and buy a house. I really think you should try out one PC-Ultra and go from there. I don't think you'll be disappointed. Good luck. Let me know if I can be of any more help.

    M i k e
     

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