Speaker/Baffle Mounting Question

[mrjim123]

I’m rebuilding an Avatar 2x10 cabinet in order to reduce overall weight (if you’re interested reference this thread: Light Weight Cab Rebuild). I plan to use ½” Arauco plywood. Dowels will be used for rigidity. The tweeter will be removed. The original Neo 10’s will be reused.

Given the thin plywood I’m not 100% confident that screws will provide a secure mount for the 10’s. I’m thinking of using bolts instead. Am I worrying needlessly about this?

There are two ways I’m thinking of doing this, each with a question (note that in the current Avatar cab the 10’s are mounted from the outside, and that’s the way I plan to mount them as well):

Method #1: Pretty standard procedure - each bolt goes through a small washer, through the speaker mouting hole, and through the baffle. It is secured with a washer, lock washer, and nut on the inside baffle surface. Using this method would require access through the cabinet back, which means I would be unable to glue the the back to the cabinet and would have to instead screw the back to the cabinet.

Method #1 Question: Is it really that desirable, as recommended by Greenboy in his fEARful designs, to glue the back on, as opposed to screwing the back on and using some kind of tape to provide an airtight seal? Which method is most commonly used to attach the back to the cabinet?

Method #2: If I could reverse the bolt direction (so that bolt head is on cabinet inside) then I could first glue the back on the cabinet and still mount the speakers from the outside to the protruding bolts.

Method #2 Question: The only was I can think of (I'm not real handy) is to secure the bolt with a lock washer and washer inside the baffle and a countersunk nut outside the baffle, and then secure the speaker to the bolt with a lock washer, washer and nut. Is there a better way to attach a threaded post to mount the speaker to? Is there a standard part for doing this?

[billfitzmaurice]

Use screws. At a load of about 1 1/4 pounds each there's no need to make things complicated by using bolts.

[tstone]

I agree that screws should work if you drill the correct size pilot hole and don't overtighten.

But if you have any doubt, Fender uses a unique part that would work for you. It's a machine screw with a short left-hand wood screw thread at the base. You screw the wood screw thread into the baffle by turning the fastener counterclockwise, thus creating a permanent mounting stud. When you tighten the speaker nut onto the projecting machine screw thread, it tends to tighten the screw into the baffle, not loosen it.

To view, go to:

Antique Electronic Supply

and type "reverse thread" into the search box.

[billfitzmaurice]

Originally Posted by tstone

Fender uses a unique part that would work for you. It's a machine screw with a short left-hand wood screw thread at the base. .

To use those the speaker must be rear-mounted, which requires a removable back, which increases the complexity of the build and adds weight. That's not the intent of the OP.

[mrjim123]

Thanks for the suggestions. I'm just going to use screws and hope for the best.

I was actually thinking ahead to possibly having to remove and re-install the speakers and thought that that might eventually strip out the screw holes but, truth be told, I'll probably never actually have to remove them.

[tstone]

Originally Posted by billfitzmaurice

To use those the speaker must be rear-mounted, which requires a removable back, which increases the complexity of the build and adds weight. That's not the intent of the OP.

Why would they have to be rear-mounted? I've used them for front-mount speakers with no problem.

You could also use tee-nuts, although you might have to grind a bit off the edges if they protruded into the speaker opening.

[will33]

I've never had a single problem mounting any speaker with wood screws, including heavy 15's and 18's. I do however glue a little extra piece of ply behind each screw hole, or just cut a ring to go behind the speakers mounting hole so I'm screwing into double thickness, 1". Then make the pilot holes a bit smaller than you normally would. The threads bite into all the plys and they hold it tight.

The other option is T-nuts or Hurricane nuts. Basically threaded inserts you press and glue in from the back, then use a small bolt and lockwasher installed from the front. Some folks just press them in or use the bolt to draw them into the wood, they can spin on you that way. A little dab of glue and a clamp and they're solid as well.

[dog1]

Originally Posted by billfitzmaurice

Use screws. At a load of about 1 1/4 pounds each there's no need to make things complicated by using bolts.

Yup. So many words for something that is a non issue.

Screw them in. They will be fine