Okay, I need some advice from you DIY sub experts. :)

Discussion in 'Home Theater Projects' started by Wayne A. Pflughaupt, Feb 22, 2004.

  1. Wayne A. Pflughaupt

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    Here’s the deal.

    Currently I have a pair of passive 12” Shivas, each in a 2.5 cubic ft. sealed box. The boxes are old tower speakers that I drafted for the job because they were laying around, and they’re stacked on their sides in a corner. Yes, it looks pretty pitiful.

    I have a chance to get from a friend a passive sub in a nice-looking 3.5 cubic ft. box. It has a 15” driver in it. However, I’ve never been particularly impressed with the way this thing performed at his place, so I’d probably like to replace the driver with something more capable.

    I love the two Shivas, but they struggle in my huge room on the most demanding action flicks, since I‘ve had to equalize them pretty drastically to get solid extension down to 25Hz. So it would be nice if I could not only make a visual improvement, but also a performance improvement. I don’t think the latter would have to be drastic – probably a 15-20% improvement would be more than adequate.

    The first thing that came to mind was a 15” Tempest, but I’m not sure only one of those in that box would do better than the two 12’s (it’s a little small, I think). Comments?

    If not the Tempest, what driver would you recommend?

    Thanks in advance.

    Regards,
    Wayne A. Pflughaupt
     
  2. RobLJ

    RobLJ Stunt Coordinator

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    How big is your 'huge' room?
     
  3. ThomasW

    ThomasW Cinematographer

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    If you're going to stay with the 3.5 cu ft box then look for a driver with a fairly low Vas. That's one of the criteria for working well in a reasonably small box.

    If 2 Shiva's aren't enough for you in the current room, then a single Tempest probably isn't going to do the trick either.

    Since you're the EQ king, consider one of the closeout BluePrint 1503's. These are very good drivers particularly for the money.... I have three of them and they are the equal of drivers costing considerably more...

    Or if you're willing to wait until they're available, and pay a little more money, the other option is the Stryke AV15
     
  4. Wayne A. Pflughaupt

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    Rob,

    6200 cubic ft. The living room opens to the kitchen dining room, etc.

    Thomas,
    Yeah, my preliminary research suggested that the Tempest might not be up to the job. Thanks for the tips on the others – I’ll definitely look into them.

    Regards,
    Wayne A. Pflughaupt
     
  5. Wayne A. Pflughaupt

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    The Blueprint a single voice coil driver, right? My amp only does 325 watts at 4 ohms, so I'm wondering if that will be sufficient?

    Another option I have - probably cheaper than buying the 1503 - would be to use the Shivas in a larger DIY cabinet. I think I could reasonably bring the volume up to 3.25 or 3.5. without substantially encroaching on living room real-estate. I imagine this would get me the extension with less EQ and would solve the headroom problem.

    But - would the larger cabinet make the bass (in music) sound "loose" or "sloppy?" That would be enough for me to sink the larger box - not willing to give up musical SQ for theater "boom."

    I don't much relish this option because I'd have to find someone to veneer it for me, but it’s not out of the question.

    Regards,
    Wayne A. Pflughaupt
     
  6. Travis Cain

    Travis Cain Stunt Coordinator

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    Are you against the idea of a vented or PR cabinet? That would be the best way to add extention.. Properly tuned, it should not make it sound loose or sloppy..
     
  7. RobLJ

    RobLJ Stunt Coordinator

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    Are you trying to stay to just one sub, or will 2 be ok? I know you've got 2 right now, but I just wonder about the ergonomics of 2 subs in your room. ie. the wife factor. My wife told me that our sub has to be out of sight or so damn pretty that she could put doilies on it.


    Also, have you looked into infinite baffle solutions?
     
  8. Pete Mazz

    Pete Mazz Supporting Actor

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    Looks like it would take ~500W with the AV15 to break even with the 2 Shivas (assuming sealed enclosures). Of course, the AV15 could handle a lot more power, but at what cost.

    Pete
     
  9. Justin Ward

    Justin Ward Supporting Actor

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    Maybe you could consider a Maelstrom? They are very efficient so you wouldn't need a ton of amp power. Of course it is a little on the large side...
     
  10. ThomasW

    ThomasW Cinematographer

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    As far as I know all the BluePrint 03 series are SVC. Powered my 1503's with a single channel of a Aragon 8008, 400 watts into a 4 ohm load. I found that my house has a 16Hz Fs [​IMG]

    I've used Shiva's in 5 cu ft cabs. Bass is nice and detailed. The output good but not in the same league as the high excursion drivers.
     
  11. Wayne A. Pflughaupt

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    Thanks for the replies, everyone.

    Answering your questions:
    Thanks for the info, Jack. That does give assurance that if I did decide to get the Shivas in a larger box, it would be an improvement.

    Regards,
    Wayne A. Pflughaupt
     
  12. ThomasW

    ThomasW Cinematographer

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    Shivas are good drivers (there's a reason I have 20 of them in various subs in my house [​IMG] ). The limiting factor is of course output.

    Your amp situation further compounds the problem.

    Here's the info on the most readily available high excursion 15"s

    AV15 2-2 ohm VCs.
    Tumults = $$$$$
    15" Titanic MKIII 4 ohm
    BP1503 4 ohm
    JBL 15" closeout at PE 4 ohm
     
  13. Wayne A. Pflughaupt

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    Hmmm. No one makes a high-excusion 15" 8-ohm sub?
     
  14. BruceD

    BruceD Screenwriter

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    Have you thought about an IB sub configuration in you room, the ultimate in best-looking-subs?
     
  15. Wayne A. Pflughaupt

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    Yes - they are appealing! But physically out of the question at this house.
     
  16. Cam McFarland

    Cam McFarland Supporting Actor

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    And so the thread ended with us left hanging.......
     
  17. Wayne A. Pflughaupt

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    Cam, were you bored last night, digging up this old thread? [​IMG]

    Well, the way the story ended: It didn’t look like I would be able to get a 15” driver that would get me the same output as the two 12s unless I also upgraded my current amplifier, and I didn’t want to spring for both – not at this time, at least. So I passed on the sub my buddy was offering.

    Worked out fine for him, though. Shortly afterwards he decided to keep it, after we did some in-room tests at his place and determined that the 10” Klipsch sub his mother-in-law gave him wasn’t doing nearly as good.

    Didn’t try to enlarge my current enclosures (or rather, build new ones!), for various reasons/issues/problems that don’t bear discussion here.

    Besides, about the same time we decided to sell the house and move to a nicer neighborhood. So it makes more sense to just wait and do whatever needs to be done when we get into the new digs.

    And they all lived – or, woofed – happily ever after! [​IMG]

    Regards,
    Wayne A. Pflughaupt
     
  18. Cam McFarland

    Cam McFarland Supporting Actor

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    yep....how'd ya guess lol, actually looking for ideas for
    the BP1503 I have coming.
     
  19. ThomasW

    ThomasW Cinematographer

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