Cab design for (4) Dayton DVC subs

Discussion in 'Home Theater Projects' started by KyleGS, Apr 8, 2005.

  1. KyleGS

    KyleGS Second Unit

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    I'm going to run (4) of the 12in DVC's sealed with a final Q of 0.7.
    I'd like a little feedback for a cabinet.

    I don't want the 4 subs run up the front of the box. (too tall)
    I don't want them side by side... (too wide)

    I don't really want two seperate boxes.

    I've tried to offset the four drivers on one face but the box is still too wide.

    If I run two subs on opposite sides will the drivers be too far apart to be coherent?
    Is this what is called a push-pull design or would they need to be out of phase?
    Educate me please... [​IMG]

    Thanks guys

    Kyle
     
  2. Allen Ross

    Allen Ross Supporting Actor

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    you are correct, if the drivers are out of phase its a push pull system.

    you could also do the drivers two on the front, two out back.
     
  3. Rory Buszka

    Rory Buszka Supporting Actor

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    Yeah, I would say build a box that is tall enough to fit two woofers in the front and two in the back. If they are wired in phase then you will be fine. Low frequency sound depends a lot more on the "pressure" side of the equation rather than the "velocity" side. A velocity source tends to radiate more in one direction, and a pressure source (when cone displacements are enough to pressurize the entire air mass) tends to radiate more throughout the room.
     
  4. Joey Skinner

    Joey Skinner Second Unit

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    Is an IB out of the questions?
     
  5. KyleGS

    KyleGS Second Unit

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    What is the difference b/w running a push-pull system and just running the subs in phase?

    What exactly is the benefit of a push-pull system?

    Thanks for the help.

    Joey- yes, unfortunately the IB is out of the question.
     
  6. Dustin B

    Dustin B Producer

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    I think you have push pull confused with dipole.

    If you have two cones facing out of a box and wired out of phase you have a dipole sub. If the drivers are right next to each other, a very bad dipole sub.

    If you have two drivers on opposite sides of a box (or any wall or combination of walls of a box really) with one having the motor structure facing out and one having the cone facing out and wired out of phase, this is a push pull. So both cones move out or into the box at the same time. But one is being pulled while the other is being pushed by it's motor. This is a push pull design and is supposed to cancel some sort of motor harmonics.
     
  7. KyleGS

    KyleGS Second Unit

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    Wow- I have some research to do. I'm going to try to read up on push-pull, dipole, and somewhere I read "bipole".
    Then you have a standard sealed box with drivers on opposite sides firing in phase like any other sealed box -- dunno what you call that one...

    From what I have read so far- I can't make much sense of it.
    ...time to put on more coffee and make another go at it...
     
  8. Dustin B

    Dustin B Producer

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    There are bipole and tripole speakers, but those designs don't really apply to subs.

    You are correct about sealed subs.

    The three other types are bass reflex (ported and passive radiator both fit in this category), bandpass and horn loaded.
     
  9. Zachery-C

    Zachery-C Extra

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    What is this sub for? Home theater? It sounds to me more like a sub for a music group. Is it possible to make it like this:
    xx
    xx
    ?
    2x2 I mean, like a half-stac.
    Secondly, you will need some insane amps, to power 4 dvcs, because they use stereo power. I would think 4 single vc subs, wire in stereo (2 subs on left = left, and two subs on right = right) would work better.. I would suggest you look into the avalanche 15's or 18's for some insane bass for a band (if thats the case). - Zack
     
  10. Rory Buszka

    Rory Buszka Supporting Actor

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    As for sound reinforcement subwoofers, you really don't want to use home hi-fi bass drivers. Home hi-fi bass drivers are engineered to reproduce frequencies that, while desirable to get the full effect of a movie or recorded music effect, are impractical to try to produce in the proper quantity in a live environment. As a result of this design approach (designing for lower resonant frequencies, smaller enclosures), driver sensitivity is pretty low, on the order of 82-89dB 1w/1m. For professional sound, drivers are only designed to get down to around 30 Hz, and to do so in relatively large volumes of air, but because of this they can design drivers that have a high sensitivity, so that less amplifier power is needed to generate the high levels, often on the order of 130dB momentary peaks. Less amplifier power means fewer amplifers, which means less initial investment for the sound company. Home theater bass is really quite expensive to reproduce, because you will generally pay $400-1000 to fill a relatively small space with bass. To fill a larger venue (like an auditorium) with the same level of output would be astronomical in cost, usually reserved only for big-budget installed SR systems, or the largest of touring shows. However, if you only try to reproduce bass down to 35 Hz instead of 25 Hz, then you can save a huge amount of money because it will take fewer speakers, and those speakers can be more efficient.
     
  11. KyleGS

    KyleGS Second Unit

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    This is for home audio use only. If I wanted pro audio or sound reinforcement I would use my Eminence Kilomax 18's.
    This is just for stereo/HT in a very large room. I would go ported but I'm partial to the sealed sound. I already have a pair of the DVC's, so two more will not cost me too much. Also I do have plenty of power to run the DVC's, I have >250w to run per sub via Yammie power amps from the early 80's (M-70 and M-85).

    The 2x2 stack will be a little too wide to look decent in my set-up. I think I'm going to run to on the front baffle and two on the opposite side.
     
  12. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    I have another idea... Think stackable or side by side separates.

    Make 4 separate sealed or vented boxes each with their own input terminal.

    Then stack them 2x2, or 4x1, or separate them into Stereo subs with Left 2x1 and Right 2x1... etc.

    This way if you think 4 subs is overkill in the future, you can sell 2 of your separate ones or move them to another room, etc...

    You'll have some flexibility.
     
  13. KyleGS

    KyleGS Second Unit

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    "overkill"... I guess I'm not familiar with that word. [​IMG]
    That is a good idea and probably the most practical for the future.

    What would be a good isolator b/w the subs if stacked not to damage the finish or shake, rattle and roll off the top?
     

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