My second DIY Subwoofer Project ....

Discussion in 'Home Theater Projects' started by Joe Mihok, May 26, 2004.

  1. Joe Mihok

    Joe Mihok Second Unit

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    Ok, I've learned alot from my first DIY Tempest I built 2 weeks ago. I guess you can say I am now addicted to low bass and want something even better than the SBB4. I've decide to do 100% of the project myself. This means I'm gonna actually create my own enclosure based on my own calculations instead of copying Adire's reference designs.

    I basically want something along the lines of the Adire Alignment, but in a 18" x 55" Sonotube enclosure. Here is the specs on the enclosure:

    - 18" Sonotube, 55" tall
    - 219 Litre enclosure
    - 64 Ounces of Polyfil
    - 6" x 32" PVC Port Tube tuned to 16hz
    - Air speed of port is 9.47 m/s @ 16hz
    - Group delay is 16 ms @ 20hz
    - Passive sub with bi-wireable binding posts (to take advantage of the DVC)


    Anyways, any thoughts on the sub plans ? Is there anything I should change or does it look fairly good ?
     
  2. Patrick Sun

    Patrick Sun Moderator
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    Did you subtract the volume of the 6" wide port from the overall enclosure? You have to treat the port as a solid cylinder inside the enclosure to arrive at the final volume targetted (219 liters, net).
     
  3. Joe Mihok

    Joe Mihok Second Unit

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    Thanks, I didn't take that into account. I just assumed the calculations would be done in LSPCAD automatically when I add the port length and tuning fequency .... I take it they are not ?

    If not then the total volume of the PVC will be 5.652 and the new volume of the enclosure will be about 213L. The new length of the port tube will be 32.48 inches.
     
  4. Patrick Sun

    Patrick Sun Moderator
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    No, LspCAD just give you net volume needed to hit a targetted tuning frequency (dependent on targetted frequency response). So that means the enclosure will be larger then the net volume (by as much as the port's cylinder takes up inside the volume). You could always put the port on the outside like a chimney if you dare.
     
  5. Joe Mihok

    Joe Mihok Second Unit

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    Thanks Patrick [​IMG] . I want the make this sub as perfect as I can. And no thanks about the chimney idea. [​IMG]
     
  6. Patrick Sun

    Patrick Sun Moderator
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    Damn, foiled again!
     
  7. Aaron Gilbert

    Aaron Gilbert Second Unit

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    Joe,

    Your plan sounds great to me. I don't see anything that needs changing. I can't believe you are dissin' the chimney port idea though, it rules! Just have a look:

    http://www.aaroncgilbert.com/images/...n/05230012.jpg

    You could even get some stove paint and make it look like a giant smoker/BBQ. Who doesn't want one of those in their living room?? [​IMG]


    Aaron Gilbert
     
  8. Kyle Richardson

    Kyle Richardson Screenwriter

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    Aaron - You should put "Kenworth" on the front of your sub and put horizontal metal bars for the driver grill. [​IMG]
     
  9. Aaron Gilbert

    Aaron Gilbert Second Unit

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    Kyle,

    Now that you mention it, it does have that sort of appearance, doesn't it? [​IMG] I'm still contemplating the grill design, it's only been a year since I put the sub into use...

    Seriously though, I actually am thinking of putting the ports inside because I'm considering standing the sub on end instead of horizontally. Right now it serves as a stand for CD and DVD racks, but now that I have built a new equipment rack/TV stand and put up my projector screen, my cheesy media racks look out of place. I've got a couple 3" precision flared ports left over from another project that would work like a charm (although I have no extraneous port noise even with my current design).


    Aaron Gilbert
     
  10. williamN

    williamN Agent

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    Joe, have you found a good source of sonotube in edmonton already?
     
  11. Joe Mihok

    Joe Mihok Second Unit

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    Yes, but they only sell in 12 ft legths. It's approx $30 CND for 12ft of 18" Sonotube. I see you live in St. Albert, did you wanna split the cost and take 6ft home ? Get back to me soon because this would be great!
     
  12. minhG

    minhG Stunt Coordinator

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    wow, that seems cheap for sonotube! $30 CND?

    And with a tempest, do you really need 6ft [​IMG]
     
  13. Joe Mihok

    Joe Mihok Second Unit

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    Well, with my Tempest I'll be coming close to 5ft [​IMG].

    I've decided to halt the sonotube project for the time being though. I figure if I purchase a BFD and flatten out my 194L SBB4, it'll be hard to beat. The sonotube will be easier to position but right now the cube is in a good spot. Only problem is this spot creates a peak @ 50-70 hz. I think a BFD should be able to fix the problem. I invested lots of time and a little bit of cash into the SBB4 so I may as well make good use of it right ? [​IMG]
     
  14. Wayne Ernst

    Wayne Ernst Cinematographer

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    Yeah, something like this:

    [​IMG]
     
  15. Aaron Gilbert

    Aaron Gilbert Second Unit

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    Wayne,

    That's pretty funny, but no offense, pretty hideous too. [​IMG] Don't the grill bars go horizontally on most trucks? I know they do in Terminator 2. Maybe that's a Peterbuilt. [​IMG]

    Aaron Gilbert
     
  16. Kyle Richardson

    Kyle Richardson Screenwriter

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    [​IMG] Too funny!
     
  17. Brian-K-Owens

    Brian-K-Owens Stunt Coordinator

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    Working right here at Peterbilt. 3 bars verticle since day one. . .

    Brian
     
  18. Stephen Cook

    Stephen Cook Auditioning

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    LOL . . . Kenworth Subs... Vertical Grille Bars.I work at K-W Dealership lol
     
  19. Rory Buszka

    Rory Buszka Supporting Actor

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    The horizontal bars are on Freightliner.
     

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