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Old 18th December 2012, 03:57 PM   #791
bcmbob is offline bcmbob  United States
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xrk971,

That is very generous of you to take the time. I have what I need for now but your math will be helpful for later projects and other builders. I did most of what you say but I was a little confused about the space outside the foam on that PDF. I went back for look at 6L6's photo to see if the foam went flush with the edge of the wood. That may be just an aesthetic consideration but I removed that extra before scaling. This entire design may not require that much detail, but I decided the slightly larger contained volume wouldn't hurt.

Thanks again.

P.S. Anyone need half a ream of good-one-side scratch paper?
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Old 18th December 2012, 05:09 PM   #792
xrk971 is offline xrk971  United States
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Ignore space beyond outside extent of channels. The grid is just there for guidelines. I think everyone has been making the foam channels come out flush to edge of faces. You are welcome.
Good luck with the build and don't let the measurements coming out discourage you - it sounds really good.

Last edited by xrk971; 18th December 2012 at 05:12 PM.
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Old 18th December 2012, 10:11 PM   #793
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Quote:
Originally Posted by bcmbob View Post
...
P.S. Anyone need half a ream of good-one-side scratch paper?
Put it back in the printer upside down, use it for your next project...

... and regarding the extension beyond the edge of the spirals, one of the original designs had two stacked spirals. The spirals were formed by cutting spiral slots in a central board and filling the slots with cut pieces of wood. The central board was therefore larger than the front and back panels.

Last edited by Don Hills; 18th December 2012 at 10:14 PM.
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Old 18th December 2012, 11:10 PM   #794
bcmbob is offline bcmbob  United States
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Whew!! Finally go some actual progress. I gave up the ghost and just bought two 2' x 4' x 1/4" birch plywood. Much better than working with the curvy old stuff. I used a spring loaded center punch relaxed to its weakest setting and had both panels done in 20 minutes.

Just to double check, I should use the same 4.5" strips even though the build is only 24" compared to the full 30" size, correct?

Might have music by tomorrow night.
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File Type: jpg Holes.JPG (106.7 KB, 332 views)
File Type: jpg Punch.jpg (91.4 KB, 311 views)
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Old 18th December 2012, 11:40 PM   #795
xrk971 is offline xrk971  United States
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Strip depth or channel height depends on driver Sd. Which driver were you using again?
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Old 18th December 2012, 11:43 PM   #796
bcmbob is offline bcmbob  United States
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Quote:
Originally Posted by xrk971 View Post
Strip depth or channel height depends on driver Sd. Which driver were you using again?
The Vifa TC9FD-18-08.
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Old 18th December 2012, 11:48 PM   #797
xrk971 is offline xrk971  United States
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The 4.5 in was for the 70 cm size with Fostex FF125wk. Vifa is smaller, measure your throat width that you just drew with the punch. That width x channel height x 2 needs to approximately equal Sd for Vifa tc9fd which Is 36.3 cm square, if I recall correctly.

Last edited by xrk971; 18th December 2012 at 11:56 PM.
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Old 19th December 2012, 12:07 AM   #798
bcmbob is offline bcmbob  United States
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Throat = 2 cm x 2 = 4 cm
4 x 9 = 36 = 3.52" width.

Correct?
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Old 19th December 2012, 12:07 AM   #799
xrk971 is offline xrk971  United States
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I just checked my old 20 in cornu plan. It was hand drawn by me and I made mods as I went along so it does not follow the plan of Planet10's pdf layout if scaled to 20 in. My throat widths were custom adjusted to 1.2 in wide. Thus my channel depth is 2.34 in ( I picked 2 and 3/8 for convenience). If you scale your pdf drawing down to 24 in, the throat, I believe will only be 0.6 and this means depth needs to be 4.7 in. This may be reason others who built the 20 incher using the pdf scaled will have too small of a throat?
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Old 19th December 2012, 12:08 AM   #800
xrk971 is offline xrk971  United States
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Quote:
Originally Posted by bcmbob View Post
Throat = 2 cm x 2 = 4 cm
4 x 9 = 36 = 3.52" width.

Correct?
No, the circle has nothing to do with it. That is cutout hole. The gap is from innermost channel edge to next adjacent channel wall.
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