Construction questions

[TonyW]

Hi, I have a few questions that may seem obvious to you experienced guys, but this is my first speaker, so I don't want to make any silly mistakes.

Background: The speakers are the Dennis Murphy Vifa Towers. Basically 38" tall, 10" wide, 12.5" deep. Internal is 8.5 X 11. Three braces at 5.5, 14, 22 from the top. Woofer/Mid is 8", center 10.25" from top; Tweeter is 1" dome, offset and ~3.5" from top.

Questions: 1. I'm planning on putting the crossover boards directly behind the drivers with the terminal box just under the second brace. Are the crossovers too close to the drivers (inductive field interference)?

2. No specs on where to put the Port, Back panel centered and about 8" from floor okay?

3. Acoustic foam 1/2" thick. Line entire interior except front baffle? How do you attach the stuff, glue or staples, if glue, what kind?

4. How sturdy are the tweeter terminals, should I "hang" the leads from the crossover from the top?

5. Wood screws or T-nuts to attach drivers and terminal box?

Thanks, Tony

[danvan]

1. I would think the boards would be far enough away, however I'd make sure they are easy to access, just in case something isn't connected very well or burns up later on, though its never happened to me.

2. Port should be just fine where you specified.

3. Personally I'd put the foam even on the front baffle, at least on the flat surfaces that are easy to cut pieces for. As for attaching the foam, use a spray-on adhesive, 3M makes good stuff, there are also knock off brands. Spray it on both surfaces (wood and foam) and let it sit for a couple of minutes before pressing them together, should hold very well. I usually put a pair of staples through it also, just to hold it on until its completely dry.

4. The terminals are probably stronger than they look, but depending on the gauge of wire you're using you could 'suspend' them. Just make sure they won't rattle, though you probably couldn't hear it anyway.

5. T-nuts would be the best way, if you have the room for them. If not, be sure to make a pilot hole, and maybe use a little handsoap in the screws when putting them in.

Hope this helps, just ask if there's anything else that you're concerned with.

[TonyW]

[B]1. I would think the boards would be far enough away, however I'd make sure they are easy to access, just in case something isn't connected very well or burns up later on, though its never happened to me.

I hadn't thought about that! I believe if I pull out the woofer I should be able to reach either crossover.

3. Personally I'd put the foam even on the front baffle, at least on the flat surfaces that are easy to cut pieces for. As for attaching the foam, use a spray-on adhesive, 3M makes good stuff, there are also knock off brands. Spray it on both surfaces (wood and foam) and let it sit for a couple of minutes before pressing them together, should hold very well. I usually put a pair of staples through it also, just to hold it on until its completely dry.

Foam in front also. I am coating the interior with a resonance damping material, hopefully the adhesive will stick to that. I'll experiment with some scrap and see.

5. T-nuts would be the best way, if you have the room for them. If not, be sure to make a pilot hole, and maybe use a little handsoap in the screws when putting them in.

I have 1/2" rabbetts 1/4" deep in 3/4" mdf, is that enough?

Thanks Danvan!

Tony

[danvan]

I use t-nuts as long as all teeth have wood to grab onto, with maybe a little overhang. You'll probably be ok if you get some small ones, certainly no bigger than a 1/4". Otherwise in all honesty I've never had a problem with wood screws, the tnuts just make it nicer to remove the drivers, should that ever be necessary.