GM-416-8B MLTL Corner Cabinet

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Originally Posted by VolvoHeretic

Thanks, I forgot the running horizontal dimensions. :) The gross volume includes the radial 2"x.75" verticals.

http://www.hostboard.com/forums/hbmc...2016/11/15.jpg

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Beautifully detailed, dimensioned and ready to 'bake'.......:Thumbs up:

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Originally Posted by VolvoHeretic

Full round-back.

http://www.hostboard.com/forums/hbmc...2016/11/16.jpg

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VolvoHeretic,

Simply Amazing! Very detailed.

For this full round-back option either 1/4" or 3/8" bending ply can be used. Front, top & bottom are 3/4" ply.

For bracing, if I understand right,

- full round-back design, with 15 of (2"X.75") braces there is no additional bracing required inside the cabinet

- curved back (octagon) design, with 7 of (2"x.75") braces no additional bracing required inside the cabinet

Hope I am right please correct otherwise.

Thank you,
Sri

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Originally Posted by GM

Took the words right out of my mouth. :D All this angle design is good experience, but folks, remember when I noted that with [ML]TLs the primary acoustic pressure was along its axis? This reduces the need for massive walls per se as long as its braced.


Now what is the most rigid, efficient shape? A cylinder. Combine the two and with some bracing along its axis, the wall can be as little as an 1/8" thick if you use a section out of sheet metal, bending wood, an appropriately large diameter cardboard concrete forming/structural tube such as 'Sonotube' or just laminating cardboard sheet over a form.


Anyway, there's myriad ways to do this and don't require fancy tools, etc., so let your imagination/needs decide how you want to do this; leaving bracing as the 'final frontier' ;) and while all this [multiple] angle stuff would seem to be needed if octogon/whatever multiple flat panel construction is desired, the reality is that the easy/lazy/cheap way now that powerful, cheap, thick, adhesives to fill large voids are available in caulk tubes, using dowels or similar of the appropriate diameter for the intended app [closet rod for large cabs is my choice] are the 'no-brainer' way to brace, tie together any angle cylindrical, stepped, slatted, cubic/whatever construction.


GM

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GM,

Thanks for the details, lots of options to consider.

I will explore little bit more on the bending plywood option for the full-round design - few stores here carries 3/8" bending ply but they are not BB, other sizes can be ordered. I found this during my 825 cabinet.

For both full-round design and curved (Octagon), based on the VolvoHeretic drawing, the vertical braces (2"x.75") should be enough and no additional bracing required. Hope I am right, please correct me otherwise.

M-19 foam link is very helpful, thanks.

-Sri

Sri, correct on the vertical bracing, except I bet that there will be a vertical handrail pole tying the middle of the top and bottom 3/4" plywood right next to the horn driver. I will have to check and see if 3/8" bending plywood is correct, you would need (2-1/2) 4x8 sheets about 6'-2" long.

You're welcome!


Not done with bracing, misc. details re damping, etc., so more to come to complete the tutorial...........


BTW, there's no such thing as 2" x0.75" lumber, only a 1x2 = .075" x 1.5", which is fine in some apps, though for 'bendy' wood curved panels a 1x3 is preferred if closet wood or similar stiffness dowel isn't used.


Note too that if 'bendy' is what you want to use, having voids isn't an issue per se since high amplitude eigenmodes is one of round/cylindrical construction's trade-offs, requiring mass damping; and look to marine apps for all the latest n' greatest in light, freeform, construction/finish construction, building supplies.


GM

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Originally Posted by GM

BTW, there's no such thing as 2" x0.75" lumber, only a 1x2 = .075" x 1.5", which is fine in some apps, though for 'bendy' wood curved panels a 1x3 is preferred if closet wood or similar stiffness dowel isn't used.GM

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You are correct GM, and you can buy nice straight clear 1x3 pine at places like Menards. I thought that there would be enough 3/4" plywood left over that Sri could cut the verticals out of the cut offs although I haven't tried marking out any 4X8 sheets to see if there will be enough. IF we use 1x3's the increased 1/2" = 0.2214 CF will reduce the overall box volume to 23.8114 CF.

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Originally Posted by VolvoHeretic

You are correct GM, and you can buy nice straight clear 1x3 pine at places like Menards. I thought that there would be enough 3/4" plywood left over that Sri could cut the verticals out of the cut offs although I haven't tried marking out any 4X8 sheets to see if there will be enough. IF we use 1x3's the increased 1/2" = 0.2214 CF will reduce the overall box volume to 23.8114 CF.

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Thanks VolvoHeretic and GM.

I will check out Menards for the 1x3 pine and dowel to get an idea. Now I am little more confident in executing curved design! I am leaning towards the curved one but, I will go thru the full-round design some more to understand especially with 3x8 ply.

Thank you,
Sri

Here is my preliminary cut list. (2) 4x8x3/4 plywood and (2-1/2) 4x8x3/8 bending plywood per speaker, so 4 sheets 3/4" and 5 sheets 3/8" total.

http://www.hostboard.com/forums/hbmc...2016/11/17.jpg

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Originally Posted by VolvoHeretic

Here is my preliminary cut list. (2) 4x8x3/4 plywood and (2-1/2) 4x8x3/8 bending plywood per speaker, so 4 sheets 3/4" and 5 sheets 3/8" total.

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VolvoHeretic,

Maybe I?m missing something here,

- The front baffle is one board and having the cut outs for horn, driver, vent (2)
- For the horn, from Model 19, a cut out required to use the foam on its sides, top, and bottom of the horn

For Curved design, is it possible to have the cut outs?

For Full-round design, you said 2-1/2 flex ply per speaker ? so, two 3/8? are sandwiched to get ?? per speaker?

Thank you,
Sri

Sri, the horn recess is there according to the dimensions GM asked for. Here is a view with everything included, I will split up the sections into details after everything is finalized. Right now, I am figuring two layers of 3/8" bending plywood, and will alter it if I am directed to do so.

http://www.hostboard.com/forums/hbmc...2016/11/18.jpg

GM, doesn't lining up the acoustic center's matter ?

Is the mouth of the HF 'it', as in...lined up with the LF ?