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Old 15th September 2009, 08:13 AM   #11
FlipC is offline FlipC  United States
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You ever gonna post the plans?
Or the HR input data?
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Old 15th September 2009, 03:04 PM   #12
jbell is offline jbell  United States
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Flip: sorry, I thought I had...
Here's my original test cabinet, and fold. I since increased the length a little to get me flat to 40, as well as reoriented the drivers 90degree, and took the suggestions to put the first horn section centered, instead of offset to the side.. I'll try to dig up some dimensions and pics if you're interested.

BTW, the 8:1 compression, no problems with 8" cones. I've had these cabinets wound up, and no issues, I'm pretty sure the small chiwaneese voice coil will melt down before I have a cone issue.
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Old 15th September 2009, 03:38 PM   #13
jbell is offline jbell  United States
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Here's construction pic. Cabinet works just as well end firing or side firing.
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Old 15th September 2009, 06:35 PM   #14
FlipC is offline FlipC  United States
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Very cool.
Thanks JBell. I am always interested. Specially for the cost.
I will be loading this #s up tonight when I get home.

What type of ply is that?
And is that 3/4 or 1/2" ...
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Old 15th September 2009, 07:19 PM   #15
jbell is offline jbell  United States
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flipc:
arauco plywood, you can find it at most lowes. It's a 5 equal ply that I was introduced to at the BFM site. Hands down better than anything but baltic in my opinion. HomeDepot does NOT have this.. their cheap china made ply is crap.

I used the 3/4" 7 ply for my big stadium TH project... Now that's some serious ply.

The key to this cabinet is the compression chamber.. change your sims by even half a liter, and things change DRAMATICALLY. (4-5 liters is where things look best)

I think you see what I did by the construction pics, and can reverse engineer from there.

from memory, here's how I assembled.

cut back, attach compression board. (compression board has a 2x4 hole in it) attach first horn path, use PL and screws to connect compression board to horn flare, and cabinet back. Attach 4"x4" ply on top of first flare. Then attach driver baffle. Attach one side, then cover first horn flare, then top. Install board that divides the last 2 flares. (I used a single piece of ply that went the entire length, driver chamber, compression, horn path) Install bracing, and front and last side. If front firing, make front 12" short for opening, if end firing, make front full length. The 'bottom' panel is full size of cabinet, and also seals rear chamber, so it's removable.

I'm sure there are other folding schemes that are more efficient that this.. but I wanted the weight of the driver at the very bottom of the cabinet, and I wanted the driver chamber easily accessible.

let me know if you actually make 'dust on this.

Last edited by jbell; 15th September 2009 at 07:23 PM.
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Old 15th September 2009, 08:28 PM   #16
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Menards also has the Arauco plywood 4' x 8'. They put it onsale alot for $20.00 a sheet.
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Old 18th September 2009, 09:44 PM   #17
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Quote:
Originally Posted by jbell View Post
flipc:
arauco plywood, you can find it at most lowes. It's a 5 equal ply that I was introduced to at the BFM site. Hands down better than anything but baltic in my opinion. HomeDepot does NOT have this.. their cheap china made ply is crap.
For my TH-Mini clone and my MCM triple-8 tapped horn, I bought the most expensive plywood that Home Depot has, and it is GARBAGE. Looks awful, doesn't cut as well as what they used to have, and splinters in big chunks.

They had baltic birch a year ago, wish they'd bring it back. I'll check out Lowes next time.
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Old 19th September 2009, 05:54 PM   #18
FlipC is offline FlipC  United States
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Well unfortunately for me I live in Alabama.
No Lowes around this area carries anything other than Georgia Pacific pine based crap.
Except for $50 a sheet oak. I have seen others using the Arauco plywood and it always looks nice. I couldn't imagine buying that at $20 a sheet.
On this last build I used some 13 ply and 9 ply China Birch.
It definitely makes a difference in weight from MDF but it also isn't 100% Birch. There are a few things thrown into it. A few had a layer of something black-ish and hard. At $32 and $38 a sheet. It is allot better than anything I can get elsewhere. My only question now is sound and duration.

Thanks for the input jbell.
I am putting this on my build list. Though I am unsure when i will get to it. I have a dual 12" layout from tb46 and also another single 12 TH to build... my addiction .... (:
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Old 19th September 2009, 07:58 PM   #19
GM is offline GM  United States
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I imagine these folks can get what you want if they don't actually stock it, so contact them to find out which type/size of the void free plywoods they can get and which local retailer you can place an order from. Both the local Lowes and HD have done it for me through their local distributor for both marine and BB ply. FWIW, the last time I priced 19 mm/13 ply BB it was ~ $61 delivered for the standard 5 ft square panel.

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Old 19th September 2009, 09:11 PM   #20
FlipC is offline FlipC  United States
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$61 a sheet... OUCH!
That wont be happening for me any time soon. I have actually talked with ML before. Nothing in stock so I just go through another local store to get what I need.
I need some more quick connects so I will stop by Lowes after work and ask
if they will get some of the Arauco in stock.
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