Dragonslayr's THT Build

After much thought and reading. I thought I'd document the process.

First, why build a THT?
Output vs cost (bang for the buck)
From what I hear, you'll spend megabucks on a commercial sub with this sort of output.

Should I build a THT - Is it hard?
I see this question asked in the forums. Since the word "hard" can be left to interpretation, I'll just say this: Building a THT takes much attention to detail. And it takes ALOT of work and time. I came to the table with some rough wood working skills and no knowledge of subwoofers. That lack of knowledge is telling. I have, now that I've figured out I can not build it in a couple of evenings, settled down into the project and changed my focus from "geterdone" to a more "getitright" approach. If you wish to go out and hammer something together in a couple of hours, the THT is not for you. But the learning experience in both wood working and finishing and subwoofer design and testing is worth it to me.



Now, what size THT to build?
The THT, by it's nature is big. Very big! Everyone seems to be happy with the 24w x 36t x 36d model which allows for a 15" subwoofer. You can also get this one thru the doorway. But it's still huge!

Now to order the plans.
This is the plan I ordered for 15.00. Maybe he'll make a paypal clickable link to simplify this someday..
http://www.billfitzmaurice.com/THT.html

Order Parts w/Parts Express Part Numbers
1 260-309 Gold Recessed 5-Way Banana Speaker Terminal Rectangle $4.87
1 295-190 Dayton DVC385-88 15" DVC Series Subwoofer $149.76
1 260-776 Cast Frame #10-32 Speaker Mounting Kit $3.39
1 260-542 Speaker Gasketing Tape 1/8" x 1/2" x 50 ft. Roll $6.48
1 260-283 Round Speaker Terminal 2-7/8" Gold Binding Post $4.98

As you can see, I've not made up my mind on the Round or square Speaker terminals.

Screws or Brads:
Screws - If you use a cheaper plywood such as Arauco (More prone to warpage, you may want to use screws. Especially if you do not have several large clamps. This may limit you to a painted type of finish.

Brads - Nice for a stained finished look. If you have lot's of clamps and good straight plywood, brads will speed up the build.

Clamps
2 - hand-held
2 - 36"

Lock and a flat washers for the 10/32 bolts.

An AMP - I'm going with a rack mount so I will be able to drive more than one subwoofer off of it and can simply run speaker wires only to it rather than a subwoofer cable. It's also suggested ground-loop hum may not be an issue this way.. I chose the EP4000 Europower 349.00 (I had first thought this mean non-US style of power plug.

3 Sheet's of 1/2 Plywood 5-Ply
Note: Have been warned against 5-ply birch that has 3 ply's, then a thin veneer ply on both sides. Better to use 5 equal size ply's. Stay away from AC Fir or BC Yellow Pine because of warpage.
NOTE: You can check the big box stores stock online.
15/32" 4X8 ARAUCO PLYWOOD ACX from lowes is cheap at 24.00, but does have a bit of a warpage issue. You may have to sort thru a few sheets.

5 tubes PL Primium adhesive from HomeDepot
Gloves (PL Primium is hard to get off of you and/or anything else.

1 1/4 and 1" drywall screws. (I have a brad nailer, but am scared of sqeaks using any sort of nail)

A plywood blade for the saw.


Tips from other threads

Air tight is a MUST!

Use 10/32 screws on the woofer to give yourself some play.

Do NOT wipe smooth PL Premium on exposed surfaces. Let it dry, then chip it off with a wood chisel. (It does NOT sand off well)

We may need to use hot glue or something on the subwoofer gasket

Use something like 5 minute epoxy on the t-nuts. Gorrilla glue may not hold!

WAF
Be aware of the "wife approval factor". For me, this is not an issue. I'd shown her one the other day where the guy knocked a hole in the wall. This morning, she had a yard stick on and was messing measuring around with it. Turned to me and asked, "Which wall were you knocking out?" Umm, I'm not knocking out a wall honey..

Notes to write on the pages of the plans:

Page 10 - Panel 4 install - Be aware panel 2 goes to the line, but panel 3 is flush with the cutout so panel 4 will underlap panel 2 and overlap panel 3. LOOK AT THE PICTURE!

The reflectors (corner braces) are differant sizes for a reason. I overlooked this and made them all the same size.. An example of a quick assumption on my part and a lesson learned.

Breaking in the SUB:
You do not HAVE to break in the driver (speaker). But many believe you should and you can do that while building the THT.
You can use a volt meter and touch the wires where they connect to the sub. Your looking for less than 10 volts at 20hz. Run that way for 24 hours. You can download test tones to play at the 20hz.
You should see movement of about 3/8" during this period.


I will edit this later as I come up with more stuff.

Thanks guys, Your making me edit it already..
Europower, to me, meant a funny looking plug end. Should have kept reading I guess.

I have loads of clamps of all sorts, but will adjust the page to reflect which ones I used on the build.

I do have a question. Would putting the thing upstairs, cutting a hole in the floor, then a vent of some sort in the ceiling work? Then, it could be a table upstairs..

On the down side, I'd expect sitting in that room would be really loud? Or would most the sound go down the vent as I'd like it to..

I did not realize this. I don't know if my Panasonic VSX-1019AHK will need something like this or not..

I have to confess, I got all the panels cut and the access panel cut and didn't take pictures yet. I'm not much of a camera person, but will try to get the wife to take some for me. She'd better hurry though. This thing is going together quick because I'm really excited about getting it working.

I did, however, update the first post to reflect the arauco plywood and the clamps I used so far.

Ok, picture taking person is on board now.. Coming up.. Stay tuned..

No time this evening, but I did sortof dry-fit a couple of panels.

See panel 1 is still rough cut about 1/2" to long


Panels 1 2 and 3 look good. Note: the overlapping of panel 3 and underlapping of panel 2 thru me off a bit. I'll note that on the first page.


Notice I cut the hole with a jig saw. It should sand down just fine.


A table saw is a godsend on these cuts. Makes me look good.


As you can make out the metel blades in the background, I'm much better setup to work on metel rather than wood. I had to buy tools for this finished wood adventure..

I removed this part of my post because I realized I was looking at it wrongly. The short reply is, I cut panel 3 down to the size it was supposed to be and all was well. As I mentioned, I'm going to create an area on the first page for "notes to make on the plans". On this particular page, it will say something like this: " Be aware panel 2 goes to the line, but panel 3 is flush with the cutout so panel 4 will underlap panel 2 and overlap panel 3. LOOK AT THE PICTURE!"

Hmm, I got the sub in. Got the amp in.
Something tells me I needed to order a cable to go between the rca looking jack on the back of the reciever to the amp.