Building Speakers Using Regular Plywood

[kvk]

I have some large partial sheets of regular old A/C plywood. I think it's either 3/4 or 5/8". I know it's > 1/2".

Just about all the plans I've browsed say birch ply or MDF.

Would it be that bad to use regular plywood?

I'm not to worried about finish. I just want to get some experience without laying out a ton of $ to get started.

I could build a 4.5" design about $100 if I use this old wood. That's not bad for a first time project to see if I have the aptitude for speaker building.

[orthoefer]

Most people avoid builder's grade plywood for speakers because of the inconsistencies in the material. Even AC plywood has voids which makes it an irregular substrate for large scale productions. You may discover one of these voids as you route a driver hole and try to attach the driver to wood that is just not there. For prototyping speakers or learning about the speaker building process, AC plywood is ok, but it you are striving to build a statement speaker, don't waste your time with this lesser material. Baltic Birch plywood is a far more pleasing product to use. Good luck.

[BlueWizard]

No, it wouldn't be bad to user regular plywood, ...as long as it is minimum 3/4" thick finish cabinet grade plywood.

The best plywood is Baltic Birch which has 12 layers (roughly) in it.

Second best is standard cabinet grade Birch, mahogany, or oak plywood which has about 8 layers in it.

Worst is common interior or exterior construction grade plywood.

Of course, you can do anything you want. The real question is, are you going to be satisfied with it when you are done?

Steve/bluewizard

[MJL21193]

Hi,
Starting here I ran some tests on three different materials, including cheap spruce sheathing.

Not much of a measurable difference.
Obviously, the way the speaker looks in the end will have a lot to do with the material it's made from. Another problem with voids in plywood is that there might be some loose material in it, which will buzz with the box vibrations.

[John L]

Originally posted by kvk
I have some large partial sheets of regular old A/C plywood. I think it's either 3/4 or 5/8". I know it's > 1/2".

Just about all the plans I've browsed say birch ply or MDF.

Would it be that bad to use regular plywood?

I'm not to worried about finish. I just want to get some experience without laying out a ton of $ to get started.

I could build a 4.5" design about $100 if I use this old wood. That's not bad for a first time project to see if I have the aptitude for speaker building.

Just use a lot of bracing.

[pjanda1]

I think AC grade will probably work fine. Many wood discussions have come and gone. I've heard plenty of folks mention potential rattles and resonances, but I've yet to hear anyone speak of experiencing them. A couple of guys have even built BIBs (large unsupported panels) with the Home Depot $25 "cabinet grade" ply. In my experience, that stuff has considerably larger and more numerous voids than AC (but that face veneer is nice for the price.) They didn't complain of any troubles. I suppose it's possible that they are making sound at a level too low to isolate as spurious noise but high enough to degrade the sound. I think if you did have an unwanted noise, so long as you could track it down, a dowel or two through the offending region would take care of it.

You've got the wood. Give it a shot and tell us your results. My money says it'll work fine.

pj

[Cal Weldon]

Originally posted by pjanda1
My money says it'll work fine.

Mine too.

To tell what thickness it is, you simply count the plies. Each is 1/8" so if you have 6 plies, it's 3/4"

[zacster]

I've used cardboard to build test speaker cabinets. You can use anything you want. Since you are really just testing the waters, go ahead with what you have. It'll surprise you how good it will sound, and then you'll want to see how it sounds with better material, then with better drivers, better wire...

[dfdye]

If you already have it, there is no harm using it as a starting point! If it ends up having problems, use something different next time (I am partial to MDF myself).

I HAVE experienced rattling/coloration using plywood in sub enclosure, so I stay away now and stick to MDF. Still, if I had a free supply of plywood and wanted to get some experience on the cheap, I wouldn't wait 2 seconds before jumping in with what I had.

David

[pjanda1]

Originally posted by dfdye

I HAVE experienced rattling/coloration using plywood in sub enclosure, so I stay away now and stick to MDF. Still, if I had a free supply of plywood and wanted to get some experience on the cheap, I wouldn't wait 2 seconds before jumping in with what I had.

I once used some of the afore mentioned, terrible home depot veneered ply in a little sub. It didn't rattle, but it leaked hugely from the driver hole to the exposed ply edge. That was a funny noise. It's amazing how much air can move through such tiny holes. It's also amazing how long those voids can be. I smeared caulk around the edge of the driver hole and filled the outer edge of the box with wood filler. No problems. It was also very thoroughly braced. Like I said though, that stuff had more/bigger voids than any AC I've seen.

pj