Foam Core Board Speaker Enclosures?

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Ravener,
Looks good. What is your reason for having the back throat leading to a spiral that goes to a closed end? Are you trying to locate the driver at a location that essentially makes the horn appear longer by having an offset driver chamber between a closed end and an open end? What is your total path length by the way? One final note, if foam core boards come in the 20x30 in size where you are (probably not as you are in Singapore), reducing the 21 in dimension to 20 in allows you to fit it on shorter length of raw stock.
 
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Tweaked the design a little, made the compression chamber rounder and the throat tighter.

fh = (342 x 0.00194m^2) / (2 * 3.142 * 0.00050m^3) = 210Hz

Seems rather reasonable...

Shall be starting work using this.

edit: upon looking at tractrix horns... mine seemed like an asymmetric curved tractrix...

Check this out from Paul Pino the foam plate speaker guy: Spinning Nautilus Speaker - YouTube
 
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Cut out the first panel for the enclosures.

Only to find out that I've bought enough materials to make only one. :spin:
 

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Thanks Carlp,
I had no idea how to do it at first. So I made the tractrix profile gauge board (the smaller piece). I cut an approximate panel and curved and glued to gauge. Then projected a 45 deg cut straight from above by eye and traced intersection with pencil. Then it still took a ittle after the fact trimming to get the two segments to line up and make a seal. Definitely make a play prototype first to learn technique. It should work though.
 
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Photos of Pair of FIB's w Soundclip

Details of Flatter is Better BIB build in the Terry Cain BIB thread. I thought since it is a foam core build, better to post final pix and sound clip here though.

They sound great and have the ability to fill the room with some nice bass. I like how they ended up looking too. I just need to decorate them now.
 

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