Construction Questions

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I've just finished the woodworking on my first pair of speakers... the Hi-Vi B3S speakers on Zaph Audio's site. Nothing very challenging since it was my first dive into any sort of woodworking - really just a box.

I have one question/experience to share. I used the B3N speaker which is round instead of the B3S which is square. This is causing a problem because if I angle the back side of the baffle, there won't be much wood left to fasten the speaker to. If I were to do it again, I would buy the B3S speaker. Any suggestions of what to do?

My second question is with regard to building more complex enclosures. While certainly not the most complicated, I want to build the Full Range Reference Project's Folded N-monopole or a BIB for a FE127E.

What is the best way to glue the braces in these types of enclosures? How do you make sure they are straight, keep them from falling over, stay in exactly the right place, etc? Do you route a mortise, or use biscuits or a small brace? Or do you just glue and hope for the best?

Finally, I can't seem to find any sites that focus on construction techniques of cabinets. Does anyone know of any where I can read about the best way to build cabinets?
 
Well, personally, I just glue the BIB interior baffles. It's not a 'hope for the best situation' though. Using the BIB as an example, careful measuring and clamping will reap rewards, and the resulting enclosure is all but bomb-proof. If you feel like routing out guides for the baffle, then that'll work fine too, so long as you get the depth right. I don't have access to all the fancy gear some people have, so I do it this way. I don't claim it to be the best, but it works for me.

I like plywood for horns anyway, and I love the appearence of the edges especially, so I like to celebrate the material, like they did in the 1920s / 1930s, and have it on display at the front.

Make the side panels the full external depth of the box, and the front, rear and interior baffles the internal box width. Makes life easier too. Cut the driver hole, and the terminal panel / holes for the binding posts. Now is the time to decide where to route the wires. I prefer to have the binding posts near the enclosure base myself.

Lay one side panel flat, and triple check all the dimensions are correct, before adding the front and rear baffles (assuming you've cut the driver's hole first). Glue and clamp. Once those are dry, measure up the position of the internal baffle. Again, triple check everything, then glue and clamp. When dry, this is the best time to add some sillicone sealant or similar at internal top, to prevent air-leaks. There's considerable internal pressure there, so take your time, and do it right. Add the damping to the front of the internal baffle, and a light layer of stuffing in the point above the driver if you wish. Fix the binding posts in position, and add the internal wire of your choice. I tend to fix it to the enclosure side-wall if I can, just to prevent it flapping in the breeze. Tape it to the outside of the driver-hole temporarily so you don't loose it and have to go dipping with a surgical retractor trying to get the end again.

Check all the measurements at least 3 times again, and add the second side-panel. Glue and clamp, and go off and have a few drinks. Or do the second speaker.

When all is dry, carefully use a metal spatular or similar to remove any excess dry glue, and drill the holes to screw the base in place. It's best to have a screw-fixing here, so you can adjust damping if necessary to your room more easily. If you want the base to be a different colour, leave it off for now, and drill holes for spikes etc, then stain and wax to your heart's content.

If there are any panels not quite true, as sometimes happens, ply being a natural material, plane them true. Then sand away to remove any surface imperfections etc. Once you've done that, and removed the dust, apply the finish of your choice. I'm not usually much of a varnish fan myself, but there are some very good ones that set like rock available now, which is useful. It brings the ply effect out beautifully, some bands pale as honey, some dark as blood. Fantastic effect I think. Some oils can do the same, but they're not as easy to use. Ditto waxes. If you want to stain them, make sure you treat it first or you'll likely end up with a very blotchy effect. Then varnish, or wax, or oil away. Lastly, add the base, and then the driver, and that's it.

Bob Brines on minimum tools: http://www.geocities.com/rbrines1/Pages/minimum_tools.html

What ply looks like when done properly:
http://www.iol.ie/~waltonaudio/ariel1.html

Actually, some of the techniques Derick used here are a nice additional follow-on to Bob's article. If you want to use something like MDF, then the same sort of things apply, but you'll have to paint or veneer it later. Bob has some nice articles on the best ways to do this on his excellent site too.

Hope this helps a bit
Scott
 
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