Thinking about going DIY, Need help with Veneer

Discussion in 'Archived Threads 2001-2004' started by Mark Fitzsimmons, Aug 4, 2002.

  1. Mark Fitzsimmons

    Mark Fitzsimmons Supporting Actor

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    Edit: Most of these questions have already been answered, feel free to review the entire thread or just refer to my most recent post with my latest questions.
    I'm thinking about going with a DIY sub and have lots of questions to help me make my decision. If I do not go DIY, then I'll be getting a SVS 25-31 PCi.
    I do not have the tools to build my own enclosure. So if I choose to go the quasi-diy route, I'll be ordering the enclosure from www.acoustic-visions.com or a comparable business - (are there any others?)
    Edit: I have decided, and begun building the enclosure myself
    -Kyle, if you happen to stumble upon this, could you be more specific on the differences between the flat kit and the one with pocket holes?
    I have size restraints. The only corner in the room where I could put it in is pretty close to me left main. It is exactly 24 inches from the left wall in the theater. My mains are on 24" stands, lets say I had a sub taller than this, the SVS for example. Would I run into any adverse effects, wouldn't this be similar to placing one of my mains next to a wall?
    I'm thinking about going with a Tempest from Adire. It seems that sealed may be better for me. Number 1, because the ported enclosures might be too big, and number 2 sealed is cheaper to make.
    What kind of extention could I get a sealed 122L Tempest?
    On the 122L Tempest plans from adire it calls for a 25.5x21.5x21.5 down firing enclosure including 4" legs. This makes the actual area the sub is in a perfect cube. I heard that cubes made bad sub enclosures?
    Now when it comes to placing this thing, we all know placing in a corner is generally best, but are there resrictions on how close it is to the walls in the corner?
    If I wanted to go for this 122L design, but deleted the legs and made it front firing, would this have any real effect on the performance?
    I think I remember reading about something that can be built (similar to a crossover) that could provide a little boost in like the last octave. Kinda a cheap way to add a little extention. Would this be an option for me?
    I have read that the Rava is a great sub for music, even better than the SVS in this regard. I believe this mostly comes from the sealed vs. ported nature. Would a sealed Tempest be the same way? It seems that having a sealed Tempest might be a great comprimise in that it is sealed so it is good for music, but still a 15" so it still has that SPL necessary for reference levels of theater.
    I'd like to keep the cost of the sub around $400. Including the Tempest, 250w PartsExpress plate amp, and leaving the rest ~$130 to have an enclosure made - I'll finish the enclosure myself.
    My goal is to match, if not exceed, the performance of a SVS 25-31 PCi while retaining the lesser cost. The way I look at it, the resale value of a DIY sub is much less than one from SVS, so I'll counter this burdon with a lower inital cost.
    Throughout this post, I've been basically talking about the mid Q 122L sealed Tempest. If you think theres a better route, I'm very open for suggestions.
    Thanks for reading my rambling, and in advance for your help.
    Regards,
    Mark Fitzsimmons
     
  2. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    I don't think your mains will have a bass reinforcement just because you added a sub to the corner.

    From what I've reserached, the shape of the subwoofer enclosure doesn't affect the sound. The wavelengths for bass are so big that standing waves don't occur plus you might be stuffing it with polyfill anyways.

    Front firing verses downfiring have no audible difference. Some drivers are capable of downfiring while all drivers are capable of front firing.

    If you buy a plate amp like the one from partsexpress you will have the option of adjusting bass boost if needed. I suggest tuning the sub after you have it built and played it in the room. You may not need to, or you might find you can live without adjusting the boost.

    The tempest should easily outperform the 25-31 SVS, I've heard it takes an Ultra to compete with the tempest in the right enclosure.

    I doubt there's an audible difference in ported sub verses sealed except for the output and response. I'd go vented for the extra output for movies if you can.
     
  3. Mark Fitzsimmons

    Mark Fitzsimmons Supporting Actor

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    No help?
     
  4. Dustin B

    Dustin B Producer

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    So you are looking at either the vented 214L or the sealed 122L. Remember Kyle should be able to knock the price down a bit if you sub a Datyon DVC15" and PE 300-794 for the Adire parts.
    I agree with everything Chris has said. Especially since you are looking at the mid Q sealed. Doubt you could tell it sound quality wise appart from the 214L vented.
    You can stick both right up to a corner, they can be physically touching both the walls of the corner if you want.
    I wouldn't bother with a LT chip for it. You don't want to kill your power handling by artificially boosting the last octave too much. A mild boost form the plate amp should be ok though (just have to swap two resistors to change this, there are a bunch of pictures on my website from when I did it).
    The Rava is a Q of 0.65, the mid Q Tempest is 0.707. So the Rava will sound some what tighter than the Tempest in that enclosure. I tried plugging the port on my Tempest the other day (260L, 6" port, under 17hz tune). There was a slight difference, but very slight to my ear on music. Sealed being better. But on the Matrix, with the port plugged it just lacked the last octave house shaking in scenes like the helicopter explosion. But I have a fairly large space to fill (open floor plan). If you are in a smaller room the sealed Tempest might do fine with some room gain.
    Download these two files and load the Adire Allignment vented and mid q sealed in LspCAD. The various graphs will give you an idea of the difference.
    http://www.adireaudio.com/Files/Adire.zip
    http://www.adireaudio.com/Files/TempestDesigns.zip
    Verses a 25-31 you won't be disappointed with either.
     
  5. Kyle Richardson

    Kyle Richardson Screenwriter

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    Well, I already let you know what I think, but then again, I'm a bit biased [​IMG]
     
  6. Mark Fitzsimmons

    Mark Fitzsimmons Supporting Actor

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    Thanks for the help guys.

    Dustin, I tried the files from Adire and it when I try to open the Tempest designs it says the project files are corrupt. What am I doing wrong?

    Can anyone estimate what kind of extention I could get from the sealed 122L tempest?

    And Dustin, my room is closed, and about 23x13ft with 7.5 foot cielings.

    If I build the Adire Alignment 214L vented, The sub enclosure would be like a wall directly to the left of my left main. Like, they would practicly be touching. I am having trouble believing that I wouldn't run into any problems with this. It seems the same as puting the speaker next to a wall.

    Again, thanks for your help.
     
  7. Jack Gilvey

    Jack Gilvey Producer

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  8. Mark Fitzsimmons

    Mark Fitzsimmons Supporting Actor

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    When will the correct files be available? Any estimates?

    I've talked to a friend who has all of the tools I'll need, and I've decided I'll just build the sub myself. I'm pretty set on 122L sealed, but I'd like to see the curves first.

    I'm planning on going with the Tempest paired with the PartsExpress 250w plate amp. I'll make the enclosure out of MDF. I know I want to make the enclosure as air tight as possible.

    What do I use to seal the interior of the enclosure, like at the edges between pieces of MDF?

    What do I use to make the driver sealed against the cabinet? And the amp?

    I'm basically looking for information that will help me when building the box.
     
  9. Dustin B

    Dustin B Producer

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    A good glue job will be air tight, especially if you use a polyurathane glue that expands. But most people around here also caulk all internal seams with silicon.

    As for the driver and amp box the favorite around here is closed cell foam weather striping. It's like a tape that you can just stick on to the driver or amp.
     
  10. Mark Fitzsimmons

    Mark Fitzsimmons Supporting Actor

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    Should I use T nuts, like the ones on the adire website, or should I just use some wood screws?
     
  11. Dustin B

    Dustin B Producer

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    If you are confindent the driver will be staying put, wood screws will work. But if the driver gets damaged, ends up defective, you end up taking it appart to fish something out that fell down the port or any other number of reasons to take it appart wood screws are a bad idea. With T-nuts you can take the thing apart as many times as you need. With wood screws, once or twice and things won't be holding that well anymore. But I guess you could just fill those holes, sping the driver, predrill new holes and mount the driver again.

    Personally I think the T-nuts are worth the little extra bit of trouble. I also found on my last sub that you can drill all the way through the endcap a whole big enough for the t-nut to hammer into. The first time I built a sub, I drilled a hole big enough for the screw all the way through and a hole big enough for the t-nut on the inside of the endcap only as deep as the t-nut would go. Which made it much harder to get the screw threaded into the t-nut when mounting the driver.
     
  12. Mark Fitzsimmons

    Mark Fitzsimmons Supporting Actor

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    Sounds like T nuts will be a good idea and worth the money and effort.

    Which T nuts should I get from the Adire website? There are three different ones to choose from.
     
  13. Dustin B

    Dustin B Producer

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    I'd just go to your local hardware store and buy the cheapest solid looking ones you can find. 1/4" threads. And some matching 1.75 or 2 inch long screws (no point and make sure the underside of the head is flat and meets the shaft at 90 degrees).
     
  14. Mark Fitzsimmons

    Mark Fitzsimmons Supporting Actor

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    Whats the best way to install polyfil? Spray adhesive?
     
  15. Dustin B

    Dustin B Producer

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    Many people here have had good success with spray adhesives. Staples also work well.
     
  16. Mark Fitzsimmons

    Mark Fitzsimmons Supporting Actor

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    I think I have some spray adhesave laying around, if I don't I'll just bust out the staple gun.

    Do you recommend just using glue to bond it all together, or use some screws on top of the glue?
     
  17. Dustin B

    Dustin B Producer

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    Are you talking about laminating the layers together, endcaps in a sonotube or putting the box together?

    In all cases glue is enough. Especially for laminating, don't want to use screws for that. For sonotube some tac nails to hold the endcap in place while it dries is helpful. For the box, if you have the right clamps no screws needed. If you don't have enough clamps then screws can make things a lot easier (just don't forget to predrill the holes).

    I thought you were going to get a flat kit from Acoustic Visions. It's my understanding that these kits have pocket screw holes all drilled for you. So it would be glue and screw no clamps needed (but they definately wouldn't hurt anything).
     
  18. Mark Fitzsimmons

    Mark Fitzsimmons Supporting Actor

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    Jack, I have checked that out before; lots of useful links.

    Dustin, I am going to be building a traditional box enclosure. I stated earlier in the the thread that I'm getting a friend who has all of the tools to help me build the sub.

    Since glue will be enough, I'll just use the glue and clamps if he has them.

    I'm probably going to buy the polyfil when I order my amp from Parts Express. Is there a better place to get it other than Parts Express? Its like $10 a pound there.
     
  19. Dustin B

    Dustin B Producer

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    Walmart or any local fabric store will have it for like a 1/4 of that. Ask for what they put in blankets if they don't know what polyfil is.

    Sorry, didn't remember that and didn't feel like reading the whole thread again. But yep, if he has enough clamps glue does more than fine (the mdf will break before a good glue joint will).
     

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