Thursday, April 29, 2010

Buschhorn Back-Loaded Horns

So, I took break with my front-loaded horn system because the weather is getting too damn nice to not have some sound in my new sunroom.  I had a pair of Fostex 103E drivers sitting around for a while and this seemed to be a perfect opportunity to employ them.  After doing some research, I settled on the Buschhorn, which is less than 7" wide and it's floor-standing, so I wouldn't have to build stands or mount a pair of monitors on the wall somehow.  You can find the plans here.  I'm going to document my build for those of you considering building a pair of back-loaded horns.

I hate veneering, so for this project, I decided on a baltic birch ply look.  It's becoming a theme in the sunroom that started with a step.  I glued up 80 layers of baltic birch, which took way longer than I anticipated.  Looking back, it could have been a lot easier if I used screws for alignment instead of just gluing the pieces.

I ended up using screws and glue on the front top and back panels of the buschhorn.  Once the glue dried, I backed the screws out and repeated with the next layer until I got past the minimum width.

Next step, sanding down flat and smooth...for this step I headed up to Wisconsin to visit my dad's shop. He has really nice tools that I use in times like this.  The surface sander is one of my favorites.  It doesn't gouge like a surface planer does, and you don't have to follow the direction of the grain.

While I was up there, I used the Steel City granite top table saw to cut all of the interior pieces. No tear out with this sucker...just straight smooth cuts.  

Next step was to route out the hole for the FE103 driver.  I used the same router template that I used for my mid-horns, but I had to modify it because the pivot point (screw) falls within the base of the router.  I ended up using two bolts on the far end of the router that I could attach after I connect the circle template to the workpiece.

This is how it turned out.

Then I cut all of the inside pieces (this is where I found out that the Buschhorn plans have incomplete information--let me know if you need the missing info).  I glued up all of the pieces of the back-loaded horn and filled the two voids with sand.

All clamps on deck for the final glue-up.

Finished.  I installed speaker grills to keep curious 10 month old hands off the drivers and added bases to keep them vertical.

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