First DIY: About to Start Adire Alignment Tempest: Need Advice

Discussion in 'Home Theater Projects' started by wad, Jan 16, 2005.

  1. wad

    wad Auditioning

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    Okay, after a long time roaming these forums, I finally decided to get started on my first DIY subwoofer. So, I registered, and before I start, thought I would ask the experts.

    My current audio:

    Receiver: Pioneer VSX-1014
    Front and Back Speakers: Polk RT55i (-3dB limits: 47Hz - 25 kHz)
    Center: CSi3

    Room Dimensions:

    20 Feet long
    15 Feet wide
    9 Foot Ceilings

    My desire is to build a subwoofer that goes down to about 16Hz with no more than a 3 dB loss. I know that sounds bold, but I figured I may as well aim high. As far as volume, I've never measured dB levels, but I know I don't listen as loud as some. My Pioneer volume rarely gets about -10 dB (and usually, that's only to see how loud I can listen).

    I'm no speaker expert, nor do I possess any math skills, so I went with the Adire ready made design. I decided on the Tempest because of the good comments it gets and because it is a very good value. If anyone out there thinks that the Adire Alignment or the Tempest is a mistake, please tell me.

    I have several questions, and at the request of the moderators in the faq, I will restrict them all to this thread.

    First, for a room of mine's size, how big of an amp will I need? In that same vein, what brands of amps should I be looking at (I think PartsExpress is all that I've really read about)?

    Second, the Adire alignment plans don't seem to have any added thickness to the baffle. Is that okay?

    Third, and I hope I don't get laughed out of the forums for this one, where in the Adire plans does a plate amp go?

    Fourth, do I need to use Adire Flared Ports, or should I use a different brand?

    Fifth, I am deciding between MDF and Baltic Birch, which is the preferred material?

    Sixth, for all those of you who have built this sub, are there any other surprises/deviations I should expect?

    I am very sorry this is so long. Thank you to all those who read this and help. I could only do this with your help. Also, if anyone wants to post a picture of their Adire Alignment subwoofer (especially if they have step by step pictures), I'd love to see it.

    Wad
     
  2. GrahamT

    GrahamT Supporting Actor

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    Welcome to HTF Wad,

    You have made a good choice with the Tempest. There are lots of good drivers but the detailed Adire plans make this one a good choice for newbies. I have a room about the same size as yours and with a BFD my Tempest is flat to 16 Hz.

    1. You should be fine with a sub plate amp with 250-360 watts. I can hit 118 dB uncorrected on the SPL meter with 250w during movies.

    2. I have built the EBS design twice, once with the single sheet and once with double thick baffle and I couldn't tell the difference.

    3. Just cut a hole any where that it will fit and is convenient.

    4. Yes pony up the dough for the flared ports. That is what the design calls for and they work perfectly.

    5. BB is preferred but it is much more expensive.

    6. Just take your time and dont cut any corners and you will have an amazing sub.

    Here is my EBS. It is the same as the AA but a little taller. Sorry the pic is so blurry. I like this way of incorporating the feet into the walls, rather than screwing something on because this thing is really heavy.

    http://clubpolk.polkaudio.com/forum/...&postid=248289
     
  3. KurtJ

    KurtJ Stunt Coordinator

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    Hi Wad,

    Welcome aboard[​IMG]

    With regards to a few of your questions:

    Amps: The plate amps (
     
  4. wad

    wad Auditioning

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    Thanks for the replies Graham and Kurt.

    So, cutting a hole for the plate amp is okay? It will not be a problem as far as air flow, etc (I guess my real question is: Will cutting a hole for the plate amp sacrifice the air-tightness of the enclosure?)?

    Also, thank you both very much for the responses. They are very helpful. Also, they make me feel like I'll be okay trying this.

    Any other comments?

    Wad
     
  5. Brian Bunge

    Brian Bunge Producer

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    wad,

    Graham is correct in saying the Tempest is an excellent choice. Concerning the plate amp, it has a gasket that seals the amp to the enclosure so you shouldn't have any issues with leaking.

    To you and Kurt:

    DO NOT use an LT circuit with a ported enclosure. They are strictly meant to be used with sealed enclosures ONLY.
     
  6. KurtJ

    KurtJ Stunt Coordinator

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    OOPS[​IMG] I forgot his will be ported. Mine was sealed.
     
  7. wad

    wad Auditioning

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    Do you guys think that the PartsExpress 300-804 (240 watts) would be enough? I've read good things about this amp.

    Is that enough, or should I jump up to the Rythmik Audio 350? They are close in price ($110 vs. $140), so I am fairly indifferent. Or should I even go to the Parts Express 300-806 (500 watts)?

    Wad
     
  8. Kyle Richardson

    Kyle Richardson Screenwriter

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    You dont need to go as large as the 300-806 if you dont want to although the parametric EQ is nice if you dont have an outboard EQ. Personally, for the money I like the Rythmik 350 with the adjustable subsonic filter and damping controls so you can fine tune the roll off to what you prefer.
     
  9. wad

    wad Auditioning

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    I bought the wood today (Baltic Birch - it was on sale).

    I have some very "this is my first time" questions.

    Do I just use glue to hold the sides together, or is it glue and screws?

    How do I hold the braces in place?

    Finally, how do I attach the legs (again, glue or glue and screws)?

    Thanks,

    Wad
     
  10. KurtJ

    KurtJ Stunt Coordinator

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    Do you have any clamps? I used a combination of clamps, screws, and biscuits to hold everything together until the glue dries. If you have few clamps, use screws to hold it together until the glue dries. Then, remove the screws and fill the holes with wood filler.

    Just go slowly, take your time, and do not rush. You may have more mistakes to fix if you hurry. (wonder how I know that?)

    I use one of those carpenters' squares to get the first corner ready. I use spring clamps to hold it against one of the walls where the other wall will join it. Then I clamp the other wall to the carpenters' square and then use glue and screws until the glue dries.

    I would probably start by gluing the 4 sides together and then put in the long brace, and then the smaller braces. Finally the top and bottom.

    Oh, and once the four sides are glued and it has dried, run a bead of caulking along the four corners to prevent any leaks. easier to do now than with all but the top or bottom attached. (No braces to get in the way. I caulked mine through the hole for the driver and amp. Not fun).

    When you cut out for the driver and amp, do not cut right along your marking line. Leave the pencil mark showing and then sand down to the line. This way, you'll be sure of a good fit.

    For the legs, I would go with ones like GrahamT has on his sub. It is easier that way than trying to make legs the correct length and positioning them on the bottom. Your sub will sit level and you will have one less thing to worry about.

    I hope this helps.

    Kurt
     
  11. wad

    wad Auditioning

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    So the screws should be removed after the glue dries? Does that mean that regular wood glue can be counted on to hold this thing together for years?

    Is there a brand of glue you recommend?

    Wad
     
  12. KurtJ

    KurtJ Stunt Coordinator

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    Yup, regular wood glue.

    Yellow glue. Any of the yellow wod glues will work. I use Titebond only because I've been using it for several years now. There's Gorilla Glue; Supposed to be the next great thing. I haven't used it though. Way more expensive than regular wood glue. Maybe someone else here has.
     
  13. wad

    wad Auditioning

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    Also, I went and bought the 64 oz of polyfill recommended. How do I stuff it? I just did a search and it came back with numerous answers. Do I line the outside, or do I just throw it in there? Also, to confirm, the braces are held only by glue? It just seems weird to me that that would be true.

    In light of all of this help, I plan on taking pictures through the whole process and posting my step by step process in building this thing. It's the least I could do.

    Wad
     
  14. Patrick Sun

    Patrick Sun Moderator
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    For a ported enclosure, polybatting (flat layers of polyfill, not the pillow stuff type) should be used to line the inside walls.

    The Glue/wood bond is pretty strong once it dries.
     
  15. KurtJ

    KurtJ Stunt Coordinator

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    I have a dado set for my table saw and a biscuit joiner which help not only with lining up but also with more surface area for the glue. These are not required, just nice to have.

    Wood glue is all you need. The screws will hold the wood tight until the glue sets. It is very strong when dry. With the void-free plywood, you don't have to worry about voids or empty pockets between the sheets of ply. So, yes, the glue will be enough.

    Remember, the screws are only needed to hold the panels together until the glue dries.
     
  16. wad

    wad Auditioning

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    This project just took a major turn for the worse. I just got an email saying that the Tempest I ordered is unavailable for delivery (backordered, I guess).

    So, given that it seems the concensus is that the Tempest won't be available for over a month, what to do now?

    I've now bought two sheets of 3/4" birch, two 3" Adire Flare Ports, and a Rythmik 350 Amp. Not to mention reserved wood shop/lumber yard work shop time for this Saturday.

    What driver should I buy that I can use the above mentioned items in (I've read a lot about the Atlas 15)? Also, how do I go about designing a box? I've tried the WinISD stuff, but it seems to require more knowledge than I have.

    Ah, so frustrating. What to do now?

    Wad
     
  17. KurtJ

    KurtJ Stunt Coordinator

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    Wad,

    I just finished a sub using the Atlas 15 and 250W Rythmik Audio Amp. I used a sealed design. 4.12Ft^3 no stuffing. For $35 more, you get XBL^2 driver, plus it looks coooel! These drivers are made to jam without lots of power.

    This sub rocks! With the 350, oh man. I can only imagine. I would go with a sealed design: Easier to design and no port length to calculate.

    My design was based on Tempest designs: cross-bracing with holes, driver placement.

    Start with the net volume you will need. In other words, what enclosure sizes are recommended. Then add the volume of the driver. Take the cube root of that volume. Metric will be in centimeters. 1L= 1000cm^3. Standard will be in feet usually. This will be the length and width of the sides of your enclosure.

    The volume of the amp is negligible, and really isn't figured in.

    I found a web site for cube root calculations,
    http://www.csgnetwork.com/cuberootcubecalc.html
    Also, I use LSPCad from Adire for my metric/standard conversions.

    Working with the design software does have a learning curve.

    An example from that website. Let's say you want an Atlas 15 in a sealed enclosure, low Qts. Website says 3.7Ft^3. OK. Add the volume of the driver. I can't recall exactly, but lets say 4l. That is .1413 Ft^3

    Now go to the website and enter in 3.8413 and the magic number is 1.56612. That's the length and width in feet of each side of your enclosure. Now convert feet to inches and you get 18.566.

    Your box size should be around 18 1/2 inches on a side. Now you have a ballpark figure to play with (figure your bracing on this size so you can add it in)

    Volume= L*W*H

    In this case, 3.8413Ft^3

    Don't like 18.5 inches? Too short, too tall? Then put in a value you like, say 20 inches because that's your favorite number.

    V= 20*W*H

    See, it's a numbers game. My bracing came in at around 2%, but I figured 10%. Most programs will say to add 10%.
     
  18. Brian Bunge

    Brian Bunge Producer

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    You could substitute the Dayton DVC 15" driver from Parts Express. It's not an exact match to the Tempest but close enough to work well in any of the recommended enclosures on Adire's site. I've built a few for customers using Adire's cabinet designs and they were thoroughly pleased.
     
  19. RobertFirment

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    I used a pile of biscuits and Gorilla Glue. No screws needed so no holes to fill.
     
  20. Scott Simonian

    Scott Simonian Screenwriter

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    Question.

    How do you do the math the calculate how much space bracing takes up? Because I am trying to figure out how tall I would have to make this new sub I want to build. I mentioned in another thread that is is a vented Atlas 15 in a 480 liter cab. I wasn't going to do a sonosub cause I thought it would be hard and maybe more expensive.

    I want to make it an "Adire-esque" cab. With the width and depth at 24", using 3/4" MDF. I wanted to use the same method of bracing as I did with my Tempest. I build it to the vented Adire Alignment spec.

    Any advice?

    EDIT: Didn't see Kurt's post up there. Uh, oh man. I didn't get a whole lot a sleep so I'm havin a little trouble thinking right now.
     

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