Need some DIY sub help!!!

Discussion in 'Home Theater Projects' started by DorianBryant, Aug 22, 2006.

  1. DorianBryant

    DorianBryant Screenwriter

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    I had a DIY 85l shiva and then went smaller to a Earthquake 10" subwoofer. Now I decided I really need a 15" subwoofer. I have an Adcom GFA-555 to power the sub. I also have a very well made 85L Shiva enclosure I would like to use.

    I have been considering the 15" Titanic. Would the Titanic work well in a downfiring selaed 85L enclosure? Would the Adcom amp be enough without the PEQ that the Dayton 1000watt plate amp offers?

    How would this work?

    Any help is greatly appreciated. Also, any other 15" options that would work in this enclosure? I can run another port or keep it sealed.
     
  2. Brent_S

    Brent_S Second Unit

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    Was that a sealed 85l Shiva? What aspects of its performance do you want to improve? Do you still have the Shiva itself, not just the cabinet?

    -Brent
     
  3. DorianBryant

    DorianBryant Screenwriter

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    It was ported to 22hz or 20? Anyway, I sold the Shiva and went in a different direction. The cabinet is quite nice and I had hoped to use it.

    I also want to jump up to a 15" subwoofer. I have a rather large and open area to fill.
     
  4. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    Well, you could try the Titanic ported. It might be a little peaky around 50-60Hz, but WinISD says its only a 1dB peak. The bigger problem will likely be port air speeds. The 85L vented Shiva box plans on the Adire site used only a 3 inch port. At least it was flared. But really a moderate excursion 12" woofer really should have a 4 inch port. And the Titanic 15 would be best with 2 4inch ports or a single 6 inch. But that would make for a really long port - virtually impossible to fit inside your enclosure.

    The easiest solution is to just seal it up - you can temporarily plug the port with a tightly rolled towel or a nerf ball to try it out. In a sealed 85 liter box, 500 watts looks about right. I don't know what the Adcom does. The 1000 watt Dayton is a bit overkill, but that's not always a bad thing. The PEQ doesn't add any power, just some tweaking flexibility. If you don't think the Adcom will work, then I'd consider the 500 watt BASH amp that's on sale for $199. http://www.partsexpress.com/pe/showd...number=300-752

    Here's another interesting idea:
    Try using the Dayton RS 15 HO subwoofer
    http://www.partsexpress.com/pe/showd...number=295-469
    This wouldn't have quite as much output as the Titanic, but it works better in your "smallish" box (for a 15" woofer, that is).

    In fact, you could actually go ported and tuned to around 22 - 23Hz and get a flat response. A 4 inch port dual flared port about 20 inches long should get you there. It'll take 500 watts and while port air speed isn't ideal at this power level, it might not be too bad. For some reason I like this idea better than the Titanic, though they're both nice woofers. If you go sealed, you might prefer the Titanic's excursion advantage.

    The SoundSplinter RLp 15 will work vented in this size box. But you'd want to use 1000 watts to have any real advantage over the Dayton woofers. And at that point a 4 inch port definitely wouldn't cut it.
     
  5. DorianBryant

    DorianBryant Screenwriter

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    The Adcom bridged, puts out 850 watts at 4 ohms. Will be plenty of power. The guys at AVS advised against the 15" in the 85l enclosure. However, it is the same size as the sealed enclosure PE sells with their kit.

    I thought if I sealed up the box, used the Adcom then I would get a close comparison to the 15" kit PE sells.
     
  6. DorianBryant

    DorianBryant Screenwriter

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    I want to use the Adcom and can spend up to $240 for a 15" driver. I can make another enclosure but am not sure what size or the driver-the options are mind boggling...
     
  7. Brent_S

    Brent_S Second Unit

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    If you want to move to a 15" driver ported, you're really going to need a new cabinet to see any significant benefit, IMO. Most of the popular 15" drivers (Titanic, RS-HiFi, DVC15, Soundsplinter) really like 6 ft^3 and larger when ported.

    Squeeze the Titanic 15 into your existing box and it has less or equal output to your old Shiva in the 20-25hz range. Go sealed, and you don't catch the Shiva's MaxSPL until 30hz.

    Put the T15 in 6 ft^3 tuned to 20hz and you've got almost the equivalent of two of your old Shiva from 20-35hz...roughly +5db, but the Shiva catches up by 50hz. Excursion limited to about 650ish watts at some frequencies.

    Get a SoundSplinter 15d2, put it in 7 ft^3 tuned to 20hz and you can handle the full 850 watts with room to spare. +6db up to about 40hz and about +3 above that compared to the Shiva. One SS 15d2 is $279...don't have the TC Sounds OEM offerings loaded up, but there may be an equivalent for a few bucks less.

    You might want to consider a pair of good quality 12" drivers in separate 3-4 ft^3 enclosures.

    -Brent
     

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