dual 8" TH build x6

[bko69]

Here is what i have been working on for the last 2 months. My brother helped me finish 2 right before the new year. i have been taking my time finishing the last 4. i have 2 more coats of duratex to put on and then load the drivers. they should be done this weekend so i can listen to them and take some measurements.

built with 1/2" 5x5 sheets of baltic birtch. each box take a little less than 1 sheet. 4 boxes for me and 2 for my brother. i can't wait to fire them up!






you can see more photos here:

Tapped Horn build


i have one extra gallon of duratex. brand new still sealed. $40 + shipping if anyone is interested.

Bob

[MaVo]

Nice work. I like the handles, something i forgot to put on every one of my horns, which often resulted in small panic situations in combination with stairways. What drivers did you use and how do the simulations look?

[cowanaudio]

G'day Bob

Nice looking box, but I'd have built, tested and tweaked one before committing to build six.

Cheers

William Cowan

[bko69]

i'm using the MCM 55-2421. oh, these are not my first. i built 2 test boxes out of MDF last november. i posted about them in this thread: How much better can i make this TH

bob

[FlipC]

They look great bko69!
Did you cut or have someone CNC that?

So no one ever chimed in about my cancellation question
in bk069's original post. IE Will having the drivers in line as such cause cancellation?

Also - what about wiring them in a push pull fashion?

[littlemike]

Cancellation is a possibility, as are phasing problems in the impulse response due to the length of L12.

However, this one is interesting, in that the whole first section could be a throat chamber, or it could be L12 and part of L23. When I build my quad-driver TH (split throats, drivers side by side, detailed in the collaborative thread), I saw a few dips that may have been cancellation related, but the response was pretty close to the predicted result so I did not sweat it. That one sounds great.

[jason_watkins]

Lookin' good bko. I recall you're near pdx metro area?

I just got the shipment notification on my mcm's. I'm targeting 30hz or lower for HT however. I think I'll steal your rather nice handle idea .

[jbell]

In your drawing, in the upper left corner, 4" and 3.5" are those values reversed?

[bko69]

i cut all the panels using a clamp on straight edge and a circular saw. a few cuts were done with a table saw. i took my time to make sure all the cuts were done right. i think it paid off because they went together very easy.

i should mention that i used PL Premium and 18 gauge brads to put these together. the PL is messy so make sure you wear something that you dont care about ruining. i then used a straight edge router bit to clean up the edges, bondo in all the brad holes, and sanded like crazy. i put on 1 coat of black latex paint on the out side, two coats in the throat area and 3 coats of duratex on the outside.

yes i live the pdx metro area. i think i got the handle idea from other boxes i looked at. i really did not want to cut another hole that could possibly leak air and 12 handles at $8 each really adds to the cost. i made a template my router could follow to cut all the handles. i think they turned out nice.


the 3.5" and 4" might be swapped. i did not have the original drawings in front of me when i made the digital drawing.


bob

[bko69]

in case anyone is interested here is how this box models. i finally figured out how to use hornresp thanks to littlemike's tutorial on the AVS forum.





bob