[wad]

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

[GrahamT]

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

[KurtJ]

Hi Wad,

Welcome aboard

With regards to a few of your questions:

Amps: The plate amps (<500W)from Adire, PartsExpress, Acoustic Visions, and Rythmik are all pretty much the same. However, I would recommend one with an LT circuit because I think it's better to have it than wish you had. It just provides a little more flexibility. I just finished my first DIY sub and bought the non-LT 250W amp from Rythmik. Now I'm thinking I should have purchased it only because of the flexibility it offers.

Materials: Start with MDF first; it's cheap enough that if you make mistakes you won't feel bad. Plus, it's practice for the BB. I used a router to make the opening for my amp but I made it too large. What to do? Make a piece of MDF to fit, cover that side with an additional 1/2" piece of MDF and be on your way. Glue it all together.

I also unintentionally drilled mounting holes for driver into the braces. I forgot the braces would make it impossible to use the T nut. What to do? Rotate the driver a few degrees, drill some more holes, and patch the other holes with bondo and keep on going.

Tools: At the minimum you'll need a circular saw, jig saw, and a drill.

I was considering a Tempest until Ascendant came along at the right time and offered an XBL^2 driver for $35 more than the Tempest. Adire's Tumult was way out of my price range.

I do have to tell you though, that you will end up with a much better sub for the money than if you bought retail. I spent $500 and my sub is way better than any $500 retail sub.



Whatever driver and amp you go with, these guys here can always help you out. So enjoy!

[wad]

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

[Brian Bunge]

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.

[KurtJ]

OOPS I forgot his will be ported. Mine was sealed.

[wad]

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

[Kyle Richardson]

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.

[wad]

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

[KurtJ]

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

[wad]

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