Wood Horn 3-way

[MatthiasA]

to get rid of the berks !

you can glue the berk sides !
then you have on both sides no berks !!!!

look at my picture
i made this for you !

[bbrown]

Matthias,
Yes, Bondo is used in auto repair and for MANY other things here in the U.S. It uses a catalyst (i.e. a two part material).

http://www.bondo.com

They have fillers, glass clothe, tons of stuff.

btw, nice job on the cabinets. The Everests will be cool.

Bruce

[John W]

Thanks for the good info, I thought I remembered seeing something similar here, but couldn’t recall where.

[MatthiasA]

did you mean this link?
http://www.audioheritage.org/vbullet...ead.php?t=4229

ive post a lot of pics during the S2600 rebuild
if you need any information about DIY and how to do - ask me!

you wooden Horns looks very very good!
i could not make it better than you!


greetings Matthias

[Uncle Paul]

I am still considering different ways to make the box. I want to curve the sides. Has anyone kerf bent mdf (a bunch of vertical kerfs all but about 3/16 of the way thru), then back filled the kerfs with bondo, like for cars, perhaps reinforced with fiberglass cloth?

Kerfing the MDF will work, but you might want to consider using bending stock to make the curved sides. Bending stock is a type of plywood where the grain all runs in the same direction. Almost any building supply outlet can order it for you.

[Mr. Widget]

I want to curve the sides. Has anyone kerf bent mdf (a bunch of vertical kerfs all but about 3/16 of the way thru),...

I am in the process of building a pair of curved walled three-ways myself... ironically even though I have made several wooden horns, this project will not feature any wooden horns.

I know of several types of bending woods used for curved laminations. There is bending poplar, which comes in thin sheets with all of the grain oriented for easy bending. There is wiggle wood, which is two plys of luan on either side of a flexible membrane, and then there are the pre-kerf'd MDF panels. You could always kerf your own, but what a pain that would be...

For speakers I would suggest the pre kerf'd MDF. Here are two sources.

http://www.neatconcepts.com/neatform.htm

http://www.outwater.com/

(Page 83 of their Architectural Products catalog)

Widget

[macaroonie]

give these guys a try http://www.aitwood.com/index.htmlthey have lots of ready formed birch ply components

[Datubie]

Very pretty! You should make & sell them!

[John W]

A quick progress update:



The boxes are coming right along. I cut the kerfs myself with the thinnest blade I had. It didn’t really take too long since there are four sides and you can flip the sides around. So it is 8 cuts before you have to reset the fence.

I did some trials and determined I could get bye with kerfs each inch.

I bent and screwed them onto the bracing, top and bottom. Then I used fiberglass reinforcing that is sold for drywall taping. This worked really well. It is sticky on one side, and is porous enough to let the bondo through and into the cracks.

I am almost ready for paint and veneer.

I have a sheet of paperbacked quartered, walnut veneer on the way.

Here are a couple pictures of the boxes in progress:

[John W]

I have also assembled the crossovers. These are using the charge-coupled n333 schematic. The caps are Axon. This is just the tweeter and mid. I am bi-amping so the woofer will be runing flat-out.

[Mr. Widget]

Your speakers are looking very nice... I can smell the Bondo from here!

Pretty funny, we are running a race and didn't even know it. I hope to have mine playable late tonight or tomorrow... they are further along than this photo from a couple of days ago. I won't be veneering mine for a while. I want to make sure they're keepers first.

Widget

[John W]

Very nice.

I like your bracing.
Is the tweeter going to be sealed within it's own box above the woofer, or is it all sharing the same space? Its hard to tell from the photo.

[Mr. Widget]

Actually in their unfinished forms I like yours better! I did get mine wired, fiberglass lined, and loaded with drivers last night. I knocked off about 1:00. I'll power them up tonight!!!

The tweeter is not in a separate chamber. The vertical bracing runs through the center of the bass cabinet. If I had continued it at the top of the bass cabinet it would run into the back of the tweeter so I split it and ran one brace on either side of the tweeter. I plan on popping in different tweeters. At this point it is still a test bed.

Widget

[GarMan]

John, you said that the woofer and mid will be crossed at 850Hz. I may be taking this too literally, but can a 1200Hz Smith Horn go down that low?

Gar.

[John W]

I am no expert at this by any means. But my understanding is you tune a horn for a given frequency and then you have some roll-off on either end.

My driver is certainly good to below 850hz and I am hoping the horn won’t drop off too much either. If anyone has any solid information on this I am anxious to hear it.

My active crossover has some variable low pass levels so I can tune it up some if I have a midbass hole.

I’ll let you know once I do some measuring.