Lightest Material for Speaker Box

[crymar]

Total newbie here. Thinking about building bookshelf speakers but want to keep the weight as low as possible. Any problem using 1/4" plywood with braced corners? Woofer size is approx. 5-6". Internal volume approx. 0.6 cu.ft..

[bullittstang]

It will be a trade-off, in that you will have cabinets resonances (unless you use a lot of braces) due to the rigidity of 1/4" stock. But if you're ok with that, or brace enough (2 side-to-side and one top-to-bottom and front-to-back at least) that it doesn't interfere with your design, you can absolutely use whatever cabinet material you want to meet your weight goals.

You might get more answers if you post in the "Tech Talk" section - this forum is for finished design/pics posting.

[billfitzmaurice]

1/4" plywood is a bit too thin, unless the panels are very well braced. You wouldn't brace the corners in any event, that's where the cabinet is inherently the strongest.

You might get more answers if you post in the "Tech Talk" section - this forum is for finished design/pics posting.

+1.

[crymar]

It will be a trade-off, in that you will have cabinets resonances (unless you use a lot of braces) due to the rigidity of 1/4" stock. But if you're ok with that, or brace enough (2 side-to-side and one top-to-bottom and front-to-back at least) that it doesn't interfere with your design, you can absolutely use whatever cabinet material you want to meet your weight goals.

You might get more answers if you post in the "Tech Talk" section - this forum is for finished design/pics posting.

Thanks for the response. Will do as advised.

[bungelow_ed]

Looks like you already have the answer you are looking for. However, you might want to consider the mechanical downside to 1/4" panel construction.

Gluing 1/4" plywood is not the easiest nor the will it result in as strong a joints as thicker panels. Expect issues unless your joints are of the highest caliber. This includes perfectly cut panels, sufficient glue in joints, adequate clamping pressure and square joints. Going to 1/2" panels will result in a significant improvement in structural strength and ease of assembly, all else being equal. There are reasons you never see commercial 1/4" plywood speaker cabinets. Just my 2 cents....

[Gordy]

[bullittstang]

I agree that 1/4" isn't the easiest to glue up, but I have made two boxes with 1/4" MDF, mitered the corners and used wood glue and some low-tack duct tape put it all together and hold it while the glue dried. I went back and put some 1/2 square stock corner blocks. After it was all dry, my test pieces broke in the middle of the MDF, not at the corners, which told me it's more than strong enough for a speaker cabinet that is typically a set-it and forget-it item.
I would again suggest using 3/8-1/2" dowels or stock for braces the panels every 6-8 inches (more if you can). They add very little weight overall, but help tremendously with rigidity and resonances.

[bill poster]

Sounds crazy but how about high density polystyrene? I remember a british speaker design using it.

[badman]

Foamcore board is a solid option that's been used with quite a bit of success. Light, rigid for weight, well damped. Driver mounting is the biggest hurdle but you can make a shell of foamcore with a wood front baffle. It's also easy to curve and brace, which can make a very high performance enclosure.

[Swerve City]

Was going to mention foamcore. My foamcore HiWave BMR TL speakers perform very well for their size. The main "problems" with foamcore are a poor finished appearance, and the need for lots of bracing on larger enclosures.

I'm not sure why weight is such a concern, but the main problem with thin panels, as mentioned, is your cuts and fitment have to be reeeeeeeeally good. Panel resonance may become a problem, which could be solved by adding dampening material, but the dampening material would add weight. Composites may work, but present a whole other set of challenges. Maybe someone here has experience with fiberglass or carbon fiber.

[joeybutts]

Uhmw?

For adhesion-
http://reltekllc.com/adhesivesforuhmw.aspx

[Beau]

Foamcore board is a solid option that's been used with quite a bit of success. Light, rigid for weight, well damped. Driver mounting is the biggest hurdle but you can make a shell of foamcore with a wood front baffle. It's also easy to curve and brace, which can make a very high performance enclosure.

Jeff is spot on. There is a guy on the DIYAUDIO forum that uses it rather extensively.

[B King]

You might check with a local lumber supplier (Not HD or Lowe's) to see if they stock MDF ultra light.

[Squidspeak]

You might check with a local lumber supplier (Not HD or Lowe's) to see if they stock MDF ultra light.

+1 1/2" ultralite MDF will give you the thicker panel for better joints and kinda light weight or maybe 3/8" thick luan plywood. Both options you would have
to get from a cabinet shop or wholesale supplier, I don't think you will find them at the Big Box stores. Good luck Mike

[dwigle]

Foamcore board is a solid option that's been used with quite a bit of success. Light, rigid for weight, well damped. Driver mounting is the biggest hurdle but you can make a shell of foamcore with a wood front baffle. It's also easy to curve and brace, which can make a very high performance enclosure.

I'd love to try it. It seems that every foam type board I google refers to foamcore. Some are used for insulation and others used for yacht hulls. Which foamcore board are you using, specifically? thanks