Best driver for a sealed box sub (music only, no HT?)

Discussion in 'Home Theater Projects' started by Javier_Huerta, Sep 8, 2003.

  1. Javier_Huerta

    Javier_Huerta Supporting Actor

    Joined:
    Mar 9, 2002
    Messages:
    619
    Likes Received:
    0
    Trophy Points:
    0
    So, now that my first project (Tempest AA) is well under way [​IMG], and with a new home project, I was thinking about building a sub for my personal system.

    The Tempest will be used for a pair of piston speakers - I think they'll sound pretty good, since both are ported. But the next sub *has* to be a sealed design, since my second system has a sealed woofer (or so my logic goes).

    Considering I'd like the best extension possible, and that my speakers can't play too loud, *and* that I'd love to go sealed, what options do I have? I was thinking about the 12" Titanic. Is there any other driver I should be considering?

    Thanks for your help!

    Javier.
     
  2. Jack Gilvey

    Jack Gilvey Producer

    Joined:
    Mar 13, 1999
    Messages:
    4,948
    Likes Received:
    0
    Trophy Points:
    0
  3. Javier_Huerta

    Javier_Huerta Supporting Actor

    Joined:
    Mar 9, 2002
    Messages:
    619
    Likes Received:
    0
    Trophy Points:
    0
    Jack, wouldn't a sealed sub be a better match for a sealed speaker than a vented one?
     
  4. Javier_Huerta

    Javier_Huerta Supporting Actor

    Joined:
    Mar 9, 2002
    Messages:
    619
    Likes Received:
    0
    Trophy Points:
    0
    I'd love to build a vented sub for my sealed speakers, but I wonder about group delay. Especially when they are electrostatics. I'd like to have the lowest group delay possible, but an IB is out of the question. Hence - the sealed sub.

    I don't care too much about group delay on the ported speakers, since they are in my living room, and I don't think I'll use them for much critical listening...
     
  5. Andrew Pratt

    Andrew Pratt Producer

    Joined:
    Dec 8, 1998
    Messages:
    3,806
    Likes Received:
    0
    Trophy Points:
    0
    Adire DPL12 is what I'd build in a 75 liter box.
     
  6. Javier_Huerta

    Javier_Huerta Supporting Actor

    Joined:
    Mar 9, 2002
    Messages:
    619
    Likes Received:
    0
    Trophy Points:
    0
    Great... thanks a lot, Andrew & Jack! I'll check out the DPL. [​IMG] [​IMG]
     
  7. dave alan

    dave alan Second Unit

    Joined:
    Aug 30, 2002
    Messages:
    256
    Likes Received:
    0
    Trophy Points:
    0
    Re: Sealed/ported sats/sub.

    Actually, it depends on the application. If you use an A/V Pre-pro or receiver with bass management, any sub is best mated to sealed mains, when the mains are set to 'small'.

    The standard HP filter is 2nd order (12 dB/octave). When applied to a sealed (2nd order roll off) speaker, the result is a 4th order, or 24 dB/octave slope.

    The standard LP filter is 4th order (24 dB/octave), which, when applied to a sub, yields a matching 4th order slope.

    OTOH, ported mains (when set to 'small') don't match any sub because the 2nd order HP filter, when applied to a ported speaker (24 dB/octave roll off + 12 dB/octave filter = 36 dB/octave), usually leaves a hole at crossover when mated with the 24 dB/octave LP filter.

    With ported mains, it's better to set them as 'large', run a sweep and graph to determine their F3, in room, and set the sub's LP to 1/2 to 1 octave above that.
     

Share This Page