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F20 braces


Lbk

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Kirby and I were talking about MDF the other day. I took him outside to my flatbed trailer and showed him a piece of 3/4" baltic birch under the tongue jack where it has been for months in a very wet period and with freezing and thawing. There it sits stained but otherwise as good as new. No delamination no warping no rotting. You want strength in all ways and good acoustics BB is what I choose to use. Here in Nashville this is what the lumber yards tell me. MDF goes into car boom boxes and BB goes into speaker cabinets. They sell so much BB that even with  the 9.75% tax a 60" x 60" x 25mm sheet costs $48.00 out the door. Music City has spoken and it's preference is BB.

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12 hours ago, Dave A said:

Kirby and I were talking about MDF the other day. I took him outside to my flatbed trailer and showed him a piece of 3/4" baltic birch under the tongue jack where it has been for months in a very wet period and with freezing and thawing. There it sits stained but otherwise as good as new. No delamination no warping no rotting. You want strength in all ways and good acoustics BB is what I choose to use. Here in Nashville this is what the lumber yards tell me. MDF goes into car boom boxes and BB goes into speaker cabinets. They sell so much BB that even with  the 9.75% tax a 60" x 60" x 25mm sheet costs $48.00 out the door. Music City has spoken and it's preference is BB.

Agreed but this time of year money is tight and time is  not. Got a good deal on some 23/32 inch plywood and thought I would give one a shoot. If it does not work out I will build another in a month using BB. I'am anxious to hear a folded horn sub.

Edited by Lbk
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Has anyone tried moving the mouth of the horn to the adjacent face? The dimensions would work better for me if the mouth was moved to the panel opposite of the woofer access panel. I have seen some tapped horn subs with options for moving the mouth to different panels (Danley I believe). I have just not seen an F20 folded horn sub configured that way. It looks as though some expansion may be lost so I don't know if it's viable. Been looking at the Lil Wrecker as well.

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On 2/19/2020 at 3:03 PM, CECAA850 said:

Leave the driver where the plans say it's supposed to be and brace like the picture above.  You'll be fine.  There's no vibration anywhere on the cabinet even when you're airing it out.

I think that's good advice since this my first f 20 build.  But would it help any if the brace next to sub was extended to run in front sub and connect to the mouth exit panel? Bad idea?

 

Hpower I like the black finish on your sub, is that duratex?

Edited by Lbk
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2 hours ago, Lbk said:

I think that's good advice since this my first f 20 build.  But would it help any if the brace next to sub was extended to run in front sub and connect to the mouth exit panel? Bad idea?

Not sure what you mean.  Are you talking about putting a brace in front of the driver?  If so it isn't necessary. 

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9 hours ago, Lbk said:

I think that's good advice since this my first f 20 build.  But would it help any if the brace next to sub was extended to run in front sub and connect to the mouth exit panel? Bad idea?

 

Hpower I like the black finish on your sub, is that duratex?

 

Yep, Duratex.

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9 hours ago, CECAA850 said:

Not sure what you mean.  Are you talking about putting a brace in front of the driver?  If so it isn't necessary. 

Yes in front of sub by extending the first brace. I will follow existing plans with above bracing, thanks!

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Just now, Lbk said:

Yes in front of sub by extending the first brace. I will follow existing plans with above bracing, thanks!

Yes, no need to brace across the face of the driver.  The driver baffle is close to adjacent panels on all 4 sides which provide support.

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6 minutes ago, CECAA850 said:

I'd estimate at least 2 quarts.  Let's see what he says.

 

Hey Carl,

He says, he can't remember but I bet your guess would be close.

 

I would suggest buying 1 gallon, and a roller.

If you keep the bucket sealed up good, your left over Duratex should last, ready for your next project.

 

https://www.parts-express.com/acry-tech-duratex-black-1-gallon-roller-grade-speaker-cabinet-coating--260-101

 

https://www.parts-express.com/acry-tech-9-textured-roller-for-duratex--260-113

 

To get a slightly smoother finish, I usually mix a very small amount of water into the Duratex.

 

Tips-for-Storing-DuraTexR.pdf

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40 minutes ago, HPower said:

 

Hey Carl,

He says, he can't remember but I bet your guess would be close.

 

I would suggest buying 1 gallon, and a roller.

If you keep the bucket sealed up good, your left over Duratex should last, ready for your next project.

 

https://www.parts-express.com/acry-tech-duratex-black-1-gallon-roller-grade-speaker-cabinet-coating--260-101

 

https://www.parts-express.com/acry-tech-9-textured-roller-for-duratex--260-113

 

To get a slightly smoother finish, I usually mix a very small amount of water into the Duratex.

 

Tips-for-Storing-DuraTexR.pdf 87.36 kB · 1 download

Sub measures approx. 51square ft. According to PE one quart will cover 20 to 24 sq ft. So looks like a gallon to be safe.

Edited by Lbk
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