enclosure debate whatchall think

[basscooker]

ok so here goes: talking the other day with a friend about how to keep the weight down on a cabinet without losing structural integrity. just using a thinner wood may be an option, since we're only going for 1x12 or 1x10. what i would like to hear from you folks is your opinion on this: what about aluminum or some other light alloy, with some sort of dampening material on the inside? goi'll be hiding back here for a bit.

[will33]

Good, smallish cabs (112/210 etc.) can be done with 3/8" ply and big cabs (215/810/subwoofer) can be done with 1/2". You just need a bracing scheme on the inside that looks a little like a ribcage. More labor intesive than slapping stuff together out of 3/4" wood. Some fiberglass guys here have done molded fiberglass sandwich type stuff that's incredibly light and at least as stiff/sturdy as a wood cab, even more laborious. Aluminum to me sounds like you'd be working against yourself the whole time.

[JimmyM]

i don't see how you could get metal to be stiff enough without making it insanely heavy or insanely expensive. there's a reason most cab makers still use plywood.

[basscooker]

well thanks! see we've already done 1/2" on a 110. the rib cage is something we didn't try, but each little rib adds weight and wouldn't it end up not much lighter than 3/4"? i'll try 3/8" to see if that helps. the aluminum idea was just (pardon the pun) trying to think outside the box. i have a buddy who works in a metalfab shop, so doing it right wouldn't be a problem. what i was really after is opinions on acoustics. ie-is wood an essential component of a good sounding speaker?

[will33]

Using 1/2", if you're using decent quality wood, you can have about a 8-10" span of before you hit a brace or the next wall. Something like a 112 would have probably 1 vertical and 1 horizontal brace per panel. A 210 or 115, depending on the shape might have an extra short run in one direction or the other. Not near as much mass as 3/4 all the way around. If you want to get a little more laborious and technical you can take a holesaw or forstner bit or something and swisscheese the bracing. If you can center and evenly/correctly space a 3/4"-7/8" hole pattern down the middle of a 2" wide bracing strip you can cut more mass without losing any structural strength at all.

[JimmyM]

Originally Posted by basscooker

ie-is wood an essential component of a good sounding speaker?

what counts is stiffness because ideally, the cab should have no resonance of its own. doesn't matter how you achieve it, though. stiffness through wood or through molded fiberglass is still stiffness. but wood's sort of cheap (compared to molded fiberglass or titanium, that is), plentiful, and easy to work with, so it wins.

[seamonkey]

You could use carbon fiber bracing like used in guitar necks these days.
Tension the panels - bow arch the panels.

The stiffer lighter materials cost more and need to be engineered and specially manufactured.

Can't be Bill Fitzmaurice designs for weight to efficiency ratio's. You need less number of cabinets and overall less weight to be way louder.

[will33]

Originally Posted by JimmyM

what counts is stiffness because ideally, the cab should have no resonance of its own. doesn't matter how you achieve it, though. stiffness through wood or through molded fiberglass is still stiffness. but wood's sort of cheap (compared to molded fiberglass or titanium, that is), plentiful, and easy to work with, so it wins.

+1

The panels should be stiff no matter what they're made of. Any panel the vibrates at all sucks sound and is wasted energy that is not coming forth as sound and can make the best speaker sound like crap.

[M0ses]

Originally Posted by seamonkey

Tension the panels - bow arch the panels.

Ee gads. Imagine calculating the volume of a box like that. I haven't taken enough calculus for that, yet.

[basscooker]

kewl. thanks for input. so that $15k molded resin prototype i have been saving to have made isn't that stoopit. super rigid, no extra hardware needed (feet, corners, handle, jack plate), and even 150 colors available- four pounds without a speaker. anyone want one when i go into production? prob go for about 100 unloaded. 1x10, 1x12.

[will33]

Even one little step towards doing it lighter, righter adds a huge amount of labor time/cost. There's a reason why everybody doesn't do it that way. If you're building it for yourself and not for sale, you can do all that, you only have to do it once (per cab) which can really add up sometimes.

[JimmyM]

Originally Posted by basscooker

kewl. thanks for input. so that $15k molded resin prototype i have been saving to have made isn't that stoopit. super rigid, no extra hardware needed (feet, corners, handle, jack plate), and even 150 colors available- four pounds without a speaker. anyone want one when i go into production? prob go for about 100 unloaded. 1x10, 1x12.

if you could seriously come up with something that sold for $100, weighed 4 lbs., was as stiff as a well braced wood cab, held up to hellacious road use like wood, and came in sparkle finishes, you would be a billionaire. come up short on any one of those and you won't be able to give them away. ok, you wouldn't have to do the sparkle finishes to sell, but nobody wants a cab that can't hold up and doesn't sound good no matter what it weighs.

[will33]

Originally Posted by JimmyM

if you could seriously come up with something that sold for $100, weighed 4 lbs., was as stiff as a well braced wood cab, held up to hellacious road use like wood, and came in sparkle finishes, you would be a billionaire. come up short on any one of those and you won't be able to give them away. ok, you wouldn't have to do the sparkle finishes to sell, but nobody wants a cab that can't hold up and doesn't sound good.

A sparkle finish in a flashy band that's a little dance oriented?.....Hmmm......

[will33]

You may have stumbled onto something here.

[M0ses]

Originally Posted by JimmyM

if you could seriously come up with something that sold for $100, weighed 4 lbs., was as stiff as a well braced wood cab, held up to hellacious road use like wood, and came in sparkle finishes, you would be a billionaire. come up short on any one of those and you won't be able to give them away. ok, you wouldn't have to do the sparkle finishes to sell, but nobody wants a cab that can't hold up and doesn't sound good no matter what it weighs.

What he said.

[JimmyM]

one other condition you'd have to meet...you'd have to be able to make large cabs, too. if all you could make were small cabs, you would still have a decent market, but you wouldn't be a billionaire.

for the record, i'm behind you. you never know...you could revolutionize cab building one day. or you could be a tremendous failure and piss away your life savings. i would move real slow on it and be very sure about what i'm doing before i drop 15 large, though.

[Passinwind]

Originally Posted by basscooker

kewl. thanks for input. so that $15k molded resin prototype i have been saving to have made isn't that stoopit. super rigid, no extra hardware needed (feet, corners, handle, jack plate), and even 150 colors available- four pounds without a speaker. anyone want one when i go into production? prob go for about 100 unloaded. 1x10, 1x12.

Be sure to read the JBL patents before you pony up for a mold...

[will33]

Ya, 15large, if that's true, it's a bass cab, not a fighter plane wing.

[basscooker]

yeah. i don't have a million dollar company backing me, or a cnc for personal use, so i gotta go "retail" for the proto. provisional patents are pending, and drafts for larger cabs are done, i'm just starting small. the material i've chosen wears like pvc but is lighter, recyclable, and rock solid. the biggest "if" so far is chipping and cold-crack tolerances. but realistically the kind of shock needed to damage the samples i have would affect any speaker's magnet, no matter the enclosure, so "void warranty" and anyone who lets their gear go sub-zero in temp deserves to pay the price <

[will33]

Anybody's gear that can't go sub-zero in the back of a truck, warm up and play the gig, over and over and over, shouldn't consider themselves reliable by any means.