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curved cabinet construction?

post #1 of 38
Thread Starter 
I'm in the planning stages for my next set of speakers, floorstanding MTM using usher 8945P midwoofers and Peerless HDS tweets. I'm considering going with a curved cabinet design, but looking for some resources.

Can anyone point me to threads involving curved cabinet construction?

Anyone wish to comment on merits of curved cabinets vs conventional boxes?

TIA!!!
post #2 of 38
Something like this maybe? http://www.zaphaudio.com/audio-speaker20a.html
post #3 of 38
That's my summer project this year too, just got a big box of RS drivers from UPS yesterday! I'm going with curved tower cabinets for looks and WAF factor because they're going in the livingroom.

Translam construction is the ideal for it's stiffness but it's also the hardest to implement. Maybe someday I'll try it if I ever want to play with high end drivers.

For this build I'll be using kerfed 3/4" MDF with maybe a 1/4" bendable ply layer on top to help even out the surface. I still need to talk to my lumberyard guys to find out if bendable ply is as stabile as MDF, if not I may try a thin 1/8" MDF lamination instead.

Good luck with your build!
post #4 of 38
Quote:
Originally Posted by dhgilmer View Post

Something like this maybe? http://www.zaphaudio.com/audio-speaker20a.html

Im re-doing my wall surrounds just like those to bad Zaph took the crossovers off the site for those He is getting ready to get into the business from what I heard so no more builds, no more tests



But maybe the OP is talking about the curved boxes I have seen in a couple of recent builds. People are using "Bendy ply" or something in those builds.
post #5 of 38
Thread Starter 
I'm talking about speakers like this:
Te mirage OMD28:


and the B&W 803s


There seems to be 2 trains of thought for building curved:

a skeleton with X number of ply's "wrapped"


or making a cross section and stacking them up (which seems like it would be more labour intensive but also have greater ridgidity:


I've seen threads about these types of builds but can't seem to find them anymore...
post #6 of 38
The cross section method looks very wasteful but to each their own.

Here is a build with the recession busters that has a curved box: http://www.avsforum.com/avs-vb/showt...ight=recession
post #7 of 38
Quote:
Originally Posted by dhgilmer View Post

The cross section method looks very wasteful but to each their own.

Here is a build with the recession busters that has a curved box: http://www.avsforum.com/avs-vb/showt...ight=recession


I was looking for Tsloms build! He did a great job!
post #8 of 38
I was thinking about this just earlier today
the best way I could think of was a basic MDF skeleton. bendy MDF wrapped round the design then an ass load of a really high density fibreglass based filler. Possibly with the addition of lead shot to really dampen well
post #9 of 38
What about an mdf skeleton and put fiberglass/resin over that. Then line the inside with sound deadening material from car audio?
post #10 of 38
Google curved plywood and/or plywood cylinders
post #11 of 38
Quote:
Originally Posted by penngray View Post

I was looking for Tsloms build! He did a great job!

Hey, thanks Penn. The only thing that I would change when I do it again would be to prebend the plywood using straps to gradually curve the plywood over a couple of days. Using the bag of salt over stands as I did with my Recession Buster speakers did not work adequately. Luckily the contact cement does a great job of bonding the layers of 1/4" plywood.

I plan on building some Econowave speakers with JBL 2226's using this curved method again. All of the parts should be here later next week. This DIY stuff is rather addictive.
post #12 of 38
This is impressive work, very nice!

post #13 of 38
Quote:
Originally Posted by tsloms View Post

Hey, thanks Penn. The only thing that I would change when I do it again would be to prebend the plywood using straps to gradually curve the plywood over a couple of days. Using the bag of salt over stands as I did with my Recession Buster speakers did not work adequately. Luckily the contact cement does a great job of bonding the layers of 1/4" plywood.

I plan on building some Econowave speakers with JBL 2226's using this curved method again. All of the parts should be here later next week. This DIY stuff is rather addictive.

lmao, Im working on my wave project but Im still figuring out the drivers and I have the NHT VR-3 project still to do first. The Econowave should be a great one!!

Im actually going with the MDF bending method for a couple of projects. 3/4" MDF, with cuts 5/8" deep ever Y inches for X inches. Ddegree of bend will determine X and Y inches, that is unknown to me still, I must experiment. All "Slits" made from the table saw will have loads of glue in them and I will bend around a pre-made frame so I form the correct shape. All good in theory!

Similar to what Zaph did in one of his builds and Im follow several bending MDF links I found online.
post #14 of 38
Another MDF construction variation I'm considering is bending the kerfed MDF around the formers with the Kerf side facing outward and then laminating 1/4" bendable wood on top to acheive a smooth surface for finishing. That may provide even stronger construction and the panels could even be premade over temporary formers so they are precurved for easier final assembly.
post #15 of 38
Kerfing picture, borrowed from FisherCustoms.com. The proprietor, BJ, is the reigning king of mobile-audio subwoofer enclosures to my knowledge.

post #16 of 38
Quote:
Originally Posted by cybe View Post

Kerfing picture, borrowed from FisherCustoms.com. The proprietor, BJ, is the reigning king of mobile-audio subwoofer enclosures to my knowledge.


The only downside I can think of to cutting these kerfs is that the curve is not smooth but instead it is a stepped curve. I like NJTEX's idea of leaving the kerf to the outside and adding the plywood over the top of it to give a smooth corner.
post #17 of 38
Quote:
Originally Posted by tsloms View Post

The only downside I can think of to cutting these kerfs is that the curve is not smooth but instead it is a stepped curve. I like NJTEX's idea of leaving the kerf to the outside and adding the plywood over the top of it to give a smooth corner.

yeah, Im going to add something over my project, something thin would be applied then veneer. I didnt know it was called Kerfing, now I have a name.

I wonder if there is anything formula on line that tells me how many notches and how far apart to cut them to get a specific degree and radius of a bend.
post #18 of 38
Quote:
Originally Posted by NJTEX View Post

Another MDF construction variation I'm considering is bending the kerfed MDF around the formers with the Kerf side facing outward and then laminating 1/4" bendable wood on top to acheive a smooth surface for finishing. That may provide even stronger construction and the panels could even be premade over temporary formers so they are precurved for easier final assembly.


If you used that method, would the outside "curve" be smooth enough to glue the plywood to? I would think each part of the curve would be too square to get a good flat seating.

I have seen a company somewhere that makes very large MDF round corners. They're totally solid pieces too. They have notches cut into the sides to glue in your 3/4" or 1" mdf panels and get a nice flush finish.
post #19 of 38
Quote:


If you used that method, would the outside "curve" be smooth enough to glue the plywood to? I would think each part of the curve would be too square to get a good flat seating.

I pretty sure You would get enough surface area to get a good enough bond, you do not need 100% coverage for wood glue to have a very, very strong bond especially since its also sealing against a flat surface that is probably +6" on the back and +12" on each side sides...thats a lot of flat adhesion. This is my case...Im curving the wood all the way around

Im going to first see how the MDF looks itself and maybe just a little sanding is needed to smooth it out.
post #20 of 38
Quote:
Originally Posted by penngray View Post

I pretty sure You would get enough surface area to get a good enough bond, you do not need 100% coverage for wood glue to have a very, very strong bond especially since its also sealing against a flat surface that is probably +6" on the back and +12" on each side sides...thats a lot of flat adhesion. This is my case...Im curving the wood all the way around

Im going to first see how the MDF looks itself and maybe just a little sanding is needed to smooth it out.

+1
I think it would be plenty strong as well. Maybe just add a little extra glue around the corners to fill in the small gaps.
post #21 of 38
Bendable ply comes in 3/8". 2 layers will give you 3/4". I use it for radius walls and staircases once in awhile. They call it wiggleboard around here. Should be perfect for an enclosure.
post #22 of 38
Anderson International Trading has all kinds of curved plywood and mdf pieces. They have Neatform flexible MDF and some other flexible plywood as well.

The nice thing about stacking the layers is that you can build the bracing into various pieces. You can also have varying wall thickness throughout the enclosure and also include the bracing into random layers. It allows you to also get close approximations to 3d shapes that you can then work with.

pics are too big so i'll just put the links in:

http://www.aespeakers.com/pics/spy/PICT0321.JPG

http://www.aespeakers.com/pics/spy/PICT0326.JPG

http://www.aespeakers.com/pics/spy/stackproto8.jpg

John
post #23 of 38
I tried stacking with my tc-1000 build which is still in progress. Ill post some pics. The advantages I found are that you can determine the thickness of your walls, its more rigid, and you can add bracing that becomes part of the enclosure. On the down side you wast a crazy amount of material and for me it took forever. I don't have a router so I had to do it all with a jig saw and then sand it smooth. It looks great but if I had to do it again I would find another way.
LL
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post #24 of 38
Of course I still need to add stain and a front baffle which I am going to make piano black. However, I am thinking of moving up in drivers so I may never do those things at all.
post #25 of 38
Quote:
Originally Posted by Hot Grits View Post

Bendable ply comes in 3/8". 2 layers will give you 3/4". I use it for radius walls and staircases once in awhile. They call it wiggleboard around here. Should be perfect for an enclosure.

Does HD or Loews have that stuff?
post #26 of 38
Quote:
Originally Posted by penngray View Post

Does HD or Loews have that stuff?

Around here they dont. Lumberyard will definitely carry it.
post #27 of 38
Quote:
Originally Posted by Hot Grits View Post

Around here they dont. Lumberyard will definitely carry it.


Thanks, I will contact my construction buddy on Monday to get a hold of some.
post #28 of 38
They also make pre-kerfed MDF. That is definitely a lumberyard item also.
post #29 of 38
Like John posted above

http://www.aitwood.com/StoreFront.As...%20Bendy%20MDF

Cool site, they even have 12 ply drum shells....hmmm, sonotube options!!

and more Veneer (good price!!)
post #30 of 38
I just skimmed the thread. I see he posted that already.
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