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Tapped Horn Sub-woofer Build- SPUD


Brac

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Starting a thread to go with my build of the TH-SPUD.-------

Budget for project is $450.00 including amp----------
Drivers are Tang Band W8-740P 8". cost on these was $126.00 for the pair.-------
It will be powered with a EUROPOWER EP1500, bought used (thanks Joesportster) total cost with xlr adapters $192.00-----
2 sheets of 3/4" Birch plywood should be $100------
That leaves $32 for misc supplies.------

Picture is someone else's build.

post-28352-13819640241922_thumb.jpg

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Brac,

Any through holes should be plugged with something like caulk to seal any potential air leaks. My units have pocket screws to join the bottom face to the baffles (and to get the initial alignment of each baffle).

The internal baffles should form a good seal against the front and back faces of the unit, i.e., the depth of the baffle and side pieces should be uniform so that when you screw the front and back pieces together--you've got a uniform sealing surface against each baffle: no "high centers" exist in the vertical baffle pieces.

If you have a router to make shallow grooves in the face pieces to accommodate better seals (and stronger, non-resonating joints), then that would probably be worth the extra effort to assure good seals.

When in doubt - caulk it in place when screwing it together.

Chris

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Picture is someone else's build.

By the way, I believe that the amount of "stuffing" used in the picture is way too much - I'd use stuffing in the high pressure area and at the mouth area of the horn - leaving everything in between open.

Chris

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I agree, I think he went way overboard with the stuffing. Did you router in groves? I've been thinking about it, and it's way more work then glue and screw. I kinda think that the DTS kit only comes that way to make it easy to assemble. I'm thinking the outside edges will get a lock-miter, then all the other pieces will get pocket screwed to the first side. Then glue and screw the second side on.

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Did you router in groves?

Yes - about 3/16" deep.

it's way more work then glue and screw

With my second SPUD, the face pieces were laid out using a makeshift router template.

I'm thinking the outside edges will get a lock-miter, then all the other pieces will get pocket screwed to the first side. Then glue and screw the second side on.

This is essentially the same process for my units.

Chris

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Finally no rain on a day I could pick up some plywood. Ended up with imported 3/4" Birch plywood at $37 per sheet.

So the mech. drawing that I have shows 11" wide side panels, but it is unclear if these go inside, outside or some type of miter. I'm hoping somebody could tell me what the finished inside dimension is, since I think even 3/4" different will really change the sub.

Just printed out the few drawings I have, thought I would ask if any of you guys that built one of these happened to save a cut list? Yes I know, I can do it, it would just save some time, which would get me cutting wood sooner. Supposed to rain for the yt next couple days, so it's a good time to be in the wood shop!

BTW. just so it is known, I have built furniture, and cabinets, but this will be my first speaker build.

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I have built furniture, and cabinets, but this will be my first speaker build

I can make this real easy for you.

Go buy some drivers of various size & shape. Mix some woofers with horns kinda thing. Start cutting on your cabinets and install said drivers in your cabinets. Temporarily disregard that which the wife is saying, tell her to simply trust you...that you heard about this on the internet.

When you are done installing various drivers in your cabinets you will be an expert with excellent experience in two areas.

1. How to install them in speaker cabinets

2. Dealing with the wife

You can trust me on this, it will work

[:^)]

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So the mech. drawing that I have shows 11" wide side panels, but it is unclear if these go inside, outside or some type of miter. I'm hoping somebody could tell me what the finished inside dimension is, since I think even 3/4" different will really change the sub.

I believe that the 11 in. dimension that you mention is the outside dimension. This means that the side panel pieces are ~9 9/16 in. depth. The MDF that I've seen actually comes in metric thicknesses - in this case, I believe it is 18 mm.

Chris

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The 11" is the outside dimension I used. I most definately encourage using a template. It will save you a ton of work in the long run. By far, these are the best subs I have ever had in my HT for the LFE channel. Incredible what two 8" woofers can do.

My tapped horn build thread is here: http://forums.klipsch.com/forums/t/142332.aspx?PageIndex=4

Good luck with the build. No, your wife isn't going to like these subs...they are rather large. Fortunately, my media room is my domain along with the garage and the shop.

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JC, I used the 8" Tang Band drivers and some of the measurements I took on the driver are on my build thread. Page 5 or so. I also took some outside sweep readings for fun. I am currently driving two of these beasts with a Behringer EP4000 pro amp, so plenty of power. A few weeks ago we watched Tron Legacy, and I swore the foundation was going to crack with the amount of pure LF bass we were getting out of that Blu Ray disk.

So far, your DBBs and the tapped horn builds have stood the test of time, which is saying something in my listening room due to my audio nervosa....upgrade-itis.

[;)]

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  • 2 months later...

Things have finally progressed, I made a template, and routed a 3/8" groove in both sides, and cut the inside pieces. Everything is a good tight fit, and is currently just tapped together. Very happy with the way the template worked, a perfect fit.--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

I still need to put the lock-miter on the outer edge, (which I will do on a friends shaper). Here are a couple photos.---------------------------------------------------------------------------------

Not sure why one driver mounts on a face and one mounts through it, but that seems to be the design.

post-28352-13819658758746_thumb.jpg

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Not sure why one driver mounts on a face and one mounts through it, but that seems to be the design.

It smooths out non-linearities of the drivers "pushing" vs. "pulling", which can be quite large nonlinearities for long throw drivers (such as these).

It also opens the throat of the horn a bit from one driver's volume protruding into the small throat area.

Chris

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Once the sides go on it has to stay closed, so how about some advise on padding, where to put it, what to buy, how much to use.

I'd use something like fiberfill from the local WalMart, Home Depot, or Lowes. I'd use about 1/2 inches to 1 inch thickness in the throat area (i.e., the "small" end of the horn), and the same in the mouth area. I'd recommend something like a 2-3 feet of this stapled in length along the horn path o both ends of the horn.

You could experiment with different amounts of stuffing added, put the sub's face sheet on, and listen (or even measure if you've got REW running on a PC with a microphone). Too much stuffing will decrease response below 25 Hz - too little will result in "mouth bounce" pulses on impulsive material.

Looking good, by the way. [;)] I think you'll like it...

Chris

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I was just doing lay-out on my acoustical exits, and realized that I only need 1, as it will most likely stand up in the rear of the room, If for some reason I needed to instead place it in front of the seats, (it would become a coffee table, not they we drink coffee in the theater) Then I would need the opening on the short side. Anyway this got me wondering, do I really need both of the "hatch panels" I can't see what you could do through the small one that you couldn't do thru the large? Or would I be better off with the Mod. I saw where an access is cut in the side ?--------------------------------------------------------------------------------------------

Also, I see wher the plans call for an speakon term. Is this the best option? Could I just drill a hole, push wire thru, and caulk the hole?--------------------------------------------------------

Thanks for all the help, can't wait to get the finished. However I am having trouble makking a final decision between lock miter and just a rabbit, for the edge panels. The lock miter is more work but leaves no exposed plywood edges...----------------------------------------------------------------------------------------------------------------------------------

For some reason the browser I'm using causes all my words to run together.....?????

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For some reason the browser I'm using causes all my words to run together.....?????

Are you using Safari on a Mac? I'm not sure if Chrome does the same thing, but Firefox is usually ok on the Mac.

On Windows, I think all the browsers work ok.

Bruce

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