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Shiva and Resistively Damped Mode

Discussion in 'Archived Threads 2001-2004' started by Ben Ven, Mar 23, 2002.

  1. Ben Ven

    Ben Ven Stunt Coordinator

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    I am new to the forum and this topic may have been covered in the past. I did a search but came empty, so I am going to ask anyone with a Shiva if they can help.
    I read in the Avatar White Paper dated back in 1999 about a resistively damped operation or RDO for short. I have had my Shiva for 1 1/2 years. It is powered by an old Pioneer Dolby Pro Logic receiver. I output the LFE chnnel from my DD receiver to the preamp input of the Pioneer. This sendds 125 W times 2 to the Shiva. Both voice coils are powered. Has anyone tried what Avatar (Adire) calls RDO. They state that if you power 1 voice coil, you can use the second voice coil as an electrmagentic brake. I was just wondering if anyone has tried this mode of operation and what it sounds like.
    Thanks.[​IMG]
     
  2. Jack Gilvey

    Jack Gilvey Producer

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    Hi Ben,

    RDO can only raise the Qts of a woofer. It'll screw up a vented alignment, and probably raise the Qtc of a sealed much too high pretty quickly. I only really see a benefit in an infinite baffle install, where the Qtc could possibly be too low.

    How are you using your Shiva?
     
  3. Ben Ven

    Ben Ven Stunt Coordinator

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    Hi Jack,

    Thanks for your reply. I am using the Shiva in a 35 L sealed enclosure, which I figure gives a Qtc of approximately 0.82. Seems like RDO is not a good idea for my highish Qtc system. I wasn't quite sure how RDO worked but now I do thanks for your input.
     
  4. Jack Gilvey

    Jack Gilvey Producer

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    Ahh, in that case it's definitely a no-go. That really is a small box for a Shiva, heavy stuffing could bring down the Qtc a bit if you haven't done that already.
     
  5. Ben Ven

    Ben Ven Stunt Coordinator

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    Tell me about it!! The only way I could keep the Shiva in my family room was to put it in the corner behind my wife's chair (she gets a real good massage when watching movies now!). She said she did not want to see that "ugly box". So, much to my dismay , I had to build the box smaller (from 60 L and that is still small) Anyway, I have stuffed it pretty good and I have about a 3dB peak centered around 85 Hz in the room. Otherwise it is pretty flat up to 125 Hz.
     
  6. Jack Gilvey

    Jack Gilvey Producer

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    That's very nice in-room response, actually. If you ever want to try something different in that box, the
    Dayton 12" DVC woofer from Parts Express is very similar to Shiva (essentially a clone), but its lower Vas makes it suitable for smaller boxes. I used it in a sealed box of just over 1 ft^3 (the details of which are about halfway down this page), and it worked out very well. Briefly mounting my Shiva in the same box really threw the inferior transient response of the much-higher Qtc into sharp relief.
     
  7. Ben Ven

    Ben Ven Stunt Coordinator

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    Thanks Jack. I will be remodelling the family room and my HT in the next year. I was actually thinking of using a pair Stryke's SAE1024.
    I would like to hear from anyone aho has experience with these drivers? And if so, how do they compare with the Shiva (they look identical and are made by the same manufacturer-Eminence)and the Parts Express 12".
    Thanks.[​IMG]
     
  8. Jack Gilvey

    Jack Gilvey Producer

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    That Stryke looks really nice as well, the quality seems excellent with that cool cast frame. [​IMG] Spec-wise, I think it's close to the PE, although they're all similar, and all three are made by Eminence. Wes Nance used the Stryke in a passive radiator project a while back, you might try a search for it.
     

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