Right Size Sub?

Discussion in 'Home Theater Projects' started by Ziuck, Jun 30, 2004.

  1. Ziuck

    Ziuck Auditioning

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    I am looking to build either a Shiva or Tempest sub or even the AV12. It will be 90% HT and 10% music. I want enough bass to fill the room and to really feel scene's like U571 depth charges. I do not want a "massive" box in the room.

    My home theater room is 13' x 19' with the entire back "wall" being open to an additional 13'x24' behind it.

    Would I be better off with a PR or Ported box? I assume sealed is out for mainly HT use. I am thinking AV12 or Shiva w/ either a PE250 amp or Rythmik 350 in a adire enclosure but not sure which one. Should I consider the tempest instead or am I completly off base with all my considerations?

    Current Setup:
    Denon 3805
    Axiom M22ti
    Axiom QS8
    Axiom VP150
    Paradign PDR8 sub
     
  2. Dean-P

    Dean-P Stunt Coordinator

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  3. ThomasW

    ThomasW Cinematographer

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    The space is quite large. It's almost impossible to have too much sub. One can always just lower the output. There are however frequent situations where people suffer buyers remorse buying too small a sub.

    If you can go with a bigger power amp I suggest building a 2' cube with 2-18 PR's from Stryke and get a BluePrint 1503 from Kyle at www.acoustic-visions.com.

    This design is my variation of what was originally called the 'Stryke Cube', that used the HE-15. I built one of these a while back and replaced the HE-15 with the BP-1503. With adequate power and a bit of EQ it will shake the walls of my 2500 sq ft brick house.

    Note that this is basically the Denali but using the lower cost BP-1503 driver instead of the much higher priced Tumult
     
  4. Darren_T

    Darren_T Second Unit

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    ThomasW,

    What wattage would you recommend with the Blueprint driver? I built the 2' cube with PRs for my MKI AV15 and am looking for possible replacement drivers in case my AV15 fails. I have the PE 500 watt plate amp...would this be sufficient? It seems to drive the AV15 well but I haven't dome enough research on other drivers. How does the BluePrint 1503 compare to the AV15? I'll have to look up the numbers I guess.
     
  5. Cam McFarland

    Cam McFarland Supporting Actor

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    Consider building an Adire Alignment enclosure using a
    Tempest driver.....that is a HUGE area.
    Add a 250-360w amp & you should be fine.

    I sure like mine.....[​IMG]
     
  6. ThomasW

    ThomasW Cinematographer

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    Darren,

    Never seen a AV-15 and never owned a plate amp. We powered the HE-15 and BP-1503 with an aragon 8008. The current owner of the 1503 cube sub is using a Adcom 565, but is in a small room.

    Note that Kyle is using a 1000 watt plate amp for the Denali. That should tell you eomething....:wink:

    For those advocating the Peerless drivers or Tempests; note that the person starting this thread said.....
     
  7. Darren_T

    Darren_T Second Unit

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    I guess it all depends on what he means by "feel". You'll "feel" it with the Tempest in that size room but you'll "FEEL" it with the drivers ThomasW recommends.

    The difference between my Tempest and the AV15 I am replacing it with is substantial. I'd consider the Blueprint driver that ThomasW mentions, I looked at the numbers and although I'm no expert the numbers look impressive to me for the $$$.
     
  8. Cam McFarland

    Cam McFarland Supporting Actor

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    I know VERY little about HT, but did find out this with my
    DIY sub....the fact that he's using a 1000w amp does not mean he needs (or can use) anymore than a 250w amp can put out.

    What do you think?
     
  9. Darren_T

    Darren_T Second Unit

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    I think ThomasW was going on the assumption I'd like to get the "most" out of the sub. I've had to adjust to ThomasW's thinking... it's taken me a bit but I think I get where he is coming from with his posts. I agree with your statement above though. I think the 500Watt plate amp would do just fine and is probably overkill in my room if calibrated correctly but the driver will handle a lot more than that.
     
  10. Cam McFarland

    Cam McFarland Supporting Actor

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    I understand completely, but I felt 250w could not possible
    be enough for my Tempest, so I went with 360w. Supposedly
    it will handle 750w, but in that enclosure, if I go past about 4 out of 10, it sounds like things are gonna come apart.
    I had been wondering if I had done something wrong or if this is typical.



    I have to add, if I paid $1800.00 for a sub, I would want to be able tell everybody it had a 1000w amp, even if I couldnt use it....[​IMG]
     
  11. ThomasW

    ThomasW Cinematographer

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    This is like the converation where one guy driving the Corvette says his car is a great sports car, and the guy driving the 'Enzo' Ferrari has a puzzled look on his face... [​IMG]

    I've been building high performance subs since the early 1970's. And yes I certainly have a different criteria for what constitutes 'adequate' performance. There's a reason there are a dozen Shiva's in my primary sub :wink:

    The driver used in a Denali is not as efficient as a Tempest. Neither is a BP-1503. And both the Tumult and the 1503 will require more EQ than a Tempest.(note this means more power is needed too) So a 250-350 watt amp maybe fine for a single Tempest. But it's not capable of powering a high-excursion sub to the SPL's that the owner of that sub should expect.

    Increasing the output level from 90dB to 100dB requires 10 TIMES more power. As an example this means going from 25 to 250 watts!

    Remember, you can never be too rich, too thin, or have too big a sub...[​IMG]
     
  12. Cam McFarland

    Cam McFarland Supporting Actor

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    Agreed...........
     
  13. Cam McFarland

    Cam McFarland Supporting Actor

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    Dang it......now you have me wanting to build a sub using
    a Tumult.



    Where can I find some plans??? [​IMG]
     
  14. ThomasW

    ThomasW Cinematographer

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    Copy the Denali if it's in your budget. You can substitute any number of several different drivers for the Tumult. Note that the Tumult's claim to fame is very low distortion. Now whether or not that distortion is audible has yet to be proven.

    The deal breaker for some people is that the 18" PR's cost a ton. If one can live with a larger ported box then one can save a bundle

    I've built 3 subs with the BP-1503. They're very good drivers. Not as 'sophisticated' as a Tumult but they're still quite good.

    Also there are some high performance car woofers that will work fine and are even less than a 1503.

    DB Drive PL15D4 . If Overstock is sold out a google search will get many other suppliers
     
  15. Darren_T

    Darren_T Second Unit

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    Question for ThomasW,

    I totally appreciate your attitude that more bass is better. I am gradually trying to get to chest pounding insane bass myself. I wish I had a 12 driver IB but that will have to wait. The wife isn't as thrilled as I am [​IMG] I'd build new subwoofers every few weeks if my wife and my budget would allow.

    My question is this...

    In your opinion, would the BP 1503 in the Stryke 24" power cube with the dual 18" PR's powered by 500 watts be a waste? In your opinion would the 500 watts be enough to push the BP driver to good performance?

    I'd buy the 1000 watt plate amp but I already have the 500 watt. I'd consider a good Pro amp but fan noise and price keep me from doing that. That and this is only my backup plan if the AV15 fails which is a 50% chance since I have the MKI which is prone to failure.

    Thanks.
     
  16. Cam McFarland

    Cam McFarland Supporting Actor

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    TW.....I actually prefer to use ports as opposed to PRs.

    I already have that dryer size AA Tempest in my room, how
    much larger of an enclosure would be required?

    I actually had been considering a sono sub for the next project.

    I saw yours on the other post....very nice. Would that
    "pressurize" a 6800 sq/ft room?
     
  17. ThomasW

    ThomasW Cinematographer

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    Darren,

    I don't have any experience with plate amps, so I really don't know.

    We've run a ported 1503 with a single channel from an Aragon 8008. Those put out 400+ watts into a 4 ohm load. Given the build quality (77lbs) I expect that Aragon watts have a bit more punch than those from a plate amp.

    So my suggestion is try your existing amp. If it's not enough sell it.

    Cam,

    I'm with you, I much prefer BIG ports over PR's. Some people can't hear a difference or need a really small box. In those instances PR's are mandatory

    Pete's ported tube sub will pressurize that room. It's a 20" diameter and 41" long tube section. Now the sub overall is taller than that of course.

    I'll let you do the math to compare it's volume to your existing sub.

    Note that the AeroPort 6" flares used in Pete's sub are no longer available. To flow the same amount of air, one must go to a 8" straight port! BIG ports are the key to avoid port 'chuffing' with these high-excursion drivers.

    Gotta run, I'll check back here later today
    Thomas...
     
  18. Cam McFarland

    Cam McFarland Supporting Actor

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    EDIT: DOOOOOOOOOOOOOH

    It would be right at 2000Cu.in smaller.....
     
  19. Ziuck

    Ziuck Auditioning

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    The seatting is only 12' away from the screen the area behind it will not need to be filled by the base. I just don't want a sub that would be "lost" with all the empty area behind the seatting area.

    I would really like to keep cost down and the box size small! [​IMG]

    Cam: You mentioned building an Adire alignment w/ the tempest. Should that be a PR or Ported? I assume you mean ported?


    Thanks for the suggestions.
     
  20. ThomasW

    ThomasW Cinematographer

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    And people in the desert want ice water.... :wink:

    There are basically 3 variables involved in designing a sub, you get to chose 2, the 3rd you can't control.

    1)cost
    2)box size
    3)output

    Small box means using PR's = increased cost (as much as adding a second driver).

    Bigger box means you can use ports = MUCH lower cost

    High output means big amp and one high-excursion driver or several lower excursion drivers
     

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