Foam Core Board Speaker Enclosures?

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Mine are oriented with the longer horns side firing.

Mine are up/down to use ceiling/floor bass enhancement as it is the smaller 20 in version. I guess you don't need anymore enhancement...:) How much space do you have behind your driver for installing the binding posts? Are you using a recessed cup or straight thru drill posts?
 
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Oh man, go to a reprographics place. They scan it, blow it up to actual size and give you two copies for $6.05 tax incl.

Any of these close to you?

Blueprinting & Reprographics in Toronto ON | YellowPages.ca

Be a manly man and draw it by hand using a square grid like the days of yore! :knight: ;) Seriously, it isn't that hard. I taped 9 sheets of 8.5 x 11 paper together and used a ruler to draw the grid and transferred by hand - you can take some liberties and hand sketch much of the curved sections. This way, it will be unique to you! This also gives you the chance to make it full smooth round spirals like I did on the micro or with sharp squares like I did on the mini. I bet it's faster than driving to a reprographics place.
 
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There are no secrets allowed in this thread - you have to fess up. :)

Speaking of aesthetics, what do you guys think about using thin veneer to glue on top of the curved exposed sections? It would look real nice. You can even veneer the top face. I haven't worked with veneers before so I don't know how easy they are to bend and apply to curves. I would imagine they might require a steam iron to soften first? Then use contact cement on the curved sections and put in place. You can get some fancy veneers like zebra wood, cocobolo, rosewood, or even plain walnut, etc.
 
I'm in. Waiting on Vifa drivers from PE. Built the first 20" spiral yesterday, it took about two and a half hours start to finish. Second one will go much faster. Lots of good tips here-Dollar Tree foamcore, hot melt glue, reprographics shop. I love the spirit of this project, really fast, cheap and open to experimentation. The use of foamcore for a speaker enclosure also seems a bit mad, crazy, off the beaten path. Thanks for sharing some of the formulas and theory, breaking it down for those of us who didn't pay attention in school. I've spent time looking at the MJK quarter-wave pages, waaay over my little head... But I am pretty good with an Xacto knife and foamcore.

I think I'm going to try T-nuts and a masonite backplate for mounting the drivers, maybe overkill. We'll see.

Would like to hear a bit more detailed experience from others about stuffing the lines. Would it work too fill a nylon bag with Acousta-Stuf with a string attached to both ends so that it could be moved or removed?
 
Thanks Cal!
You're welcome Iko.
Hey guys, how long do you think before the original author of the Cornu will come here and be real disgusted with the way we're butchering his beautiful design?
Disgusted? I think of it as a form of flattery. :)

His design? There were others in the past and I don't see a patent, an application for a patent or anything. Daniel does seem to have some patents in other fields but not boxes so may this is his adaptation and application of an idea.
 
Founder of XSA-Labs
Joined 2012
Paid Member
I'm in. Waiting on Vifa drivers from PE. Built the first 20" spiral yesterday, it took about two and a half hours start to finish. Second one will go much faster. Lots of good tips here-Dollar Tree foamcore, hot melt glue, reprographics shop. I love the spirit of this project, really fast, cheap and open to experimentation. The use of foamcore for a speaker enclosure also seems a bit mad, crazy, off the beaten path. Thanks for sharing some of the formulas and theory, breaking it down for those of us who didn't pay attention in school. I've spent time looking at the MJK quarter-wave pages, waaay over my little head... But I am pretty good with an Xacto knife and foamcore.

I think I'm going to try T-nuts and a masonite backplate for mounting the drivers, maybe overkill. We'll see.

Would like to hear a bit more detailed experience from others about stuffing the lines. Would it work too fill a nylon bag with Acousta-Stuf with a string attached to both ends so that it could be moved or removed?

Surfacetension,
That's awesome that you are trying the mini 20 incher with the Vifas. Two and half hours on your first one is very good - you are handy! The masonite backplate with T-nuts is a great idea, hot glue it on the back and hot glue the nuts to the board so they don't fall off. I use use a small 3/8 x 1/2 in piece of masonite glued to the back where each screw goes. That's a clever idea with the bag with strings on both ends! I put stuffing in first 4 or 5 inches of throat entrance downwards - loosely. I stuff the main cavity dense though. The foam core is crazy but you will be amazed by how it sounds. Make sure you hang it on wall to test as the room ceiling and floors play big role.
Good luck and keep us posted.:) Any photos of your 20 inch spiral?
Regards,
Xrk971
 
Does peel and stick veneer bend easily?

in the long grain direction, yes - cross grain can be a bit trickier (varies a bit by species) - use a wooden roller or block to roll over the edges and sand out light bruising with 150 to 220G paper on a soft block

less margin for error and working time for grain matching/alignment on PSA backed veneers than the old school DIY iron on method