Aluminum baffle panels

[joecarrow]

Hi All,

I just read some of the posts in the Tangband thread, and the topic of aluminum baffle panels came up. I've been interested in this ever since I first saw the Aurasound NS3-193's in person- the baffle really has to be chamfered from behind to get any airspace!

I did some searching, and this was the only thread I came up with a discussion of these milled plates to support drivers with restricting baskets. Has anybody here had any luck making or using such plates?

A while ago I found a place called emachineshop.com. I don't know if they're any good, but simple parts are supposed to be fairly reasonable and the cost goes down with volume. Any experiences? Any opinions?

[Brian C.]

Dunno...

Do I understand correctly that Jon was talking about making the front baffle out of 1/4" Aluminum sheet? I'd be concerned that it would introduce it's own resonance. Thicker material probably wouldn't do it, but then it gets expensive, and HEAVY.

I regularly machine whatever I need out of aluminum. Mostly quad/dirtbike parts, hot rod parts, trim bezels for vehicles, what-have-you. Router templates have been known to cross my CNC mill, as well.

Perhaps I need to start a service doing speaker cabinet work on the side?

:W

[ThomasW]

For decades Jon and I have used baffle inserts made from aluminum plate. They're aren't large enough to have significant resonances. And any resonances they do have can be damped with bituminous sheets.

Most of the time the driver cutouts were made with a jigsaw. The driver's flange covers any irregularities in the hole.

[joecarrow]

It's not the full baffle. As I understand it, you would have a normal wood baffle with a square cutout just larger than the driver. There would only be a small unsupported span of 1/4" aluminum, so it would be stiff enough to do the job.

Edit- Thomas, it looks like you posted just before me. Cutting 1/4" aluminum with a jigsaw sounds loud!

[Jim Holtz]

For decades Jon and I have used baffle inserts made from aluminum plate. They're aren't large enough to have significant resonances. And any resonances they do have can be damped with bituminous sheets.

Most of the time the driver cutouts were made with a jigsaw. The driver's flange covers any irregularities in the hole.

Thomas,

I searched and tried to find these panels and didn't come up with a good link. I went to McMaster and the only ones I found were very expensive. Where are you sourcing them?

Thanks!

Jim

[Brian C.]

For decades Jon and I have used baffle inserts made from aluminum plate. They're aren't large enough to have significant resonances. And any resonances they do have can be damped with bituminous sheets.

Most of the time the driver cutouts were made with a jigsaw. The driver's flange covers any irregularities in the hole.

Ahhh... I follow you now...

So this is something that could easily be produced in quantity... (I've got plenty of drops of 1/4" 6061-T6 laying around... )

[Edge540]

If your looking for aluminum sheet, you may want to check this place out. http://www.yardstore.com/ . They are located in Wichita and basicly resell cut-offs of all materials the aircraft companies use. Metals are usually sold by the pound, not pysical size. They have tons of stuff. Your titanium baffle might become a reality, but cutting/milling this stuff is most difficult.
There is another place called Boeing Salvage in Wichita, but you must pick up your order personally.
p.s. Im not affiliated with them in anyway, just a happy customer.
Thanks,
Eric

[JonMarsh]

Ahhh... I follow you now...

So this is something that could easily be produced in quantity... (I've got plenty of drops of 1/4" 6061-T6 laying around... )

You've got the idea- since we're talking about small drivers, and typically combinations of small midwoofer/midrange and tweeter, think 6" X 12" panels. Available at reasonable price from McMaster-Carr, for example. (~$18 each)

[Brian C.]

You've got the idea- since we're talking about small drivers, and typically combinations of small midwoofer/midrange and tweeter, think 6" X 12" panels. Available at reasonable price from McMaster-Carr, for example. (~$18 each)

That's REASONABLE?!??! :E

Holy Cow, Jon!!

Our current cost for .250" Aluminum, including cut charges, PVC coating on both sides (to make sure it shows up nice and pretty), AND delivery, is less than HALF that!!

Tell you what... If any of you guys want these baffle plates, and can provide me with ACCURATE drawings, I'll do 'em for ya. $25.... includes cost of material (based on Jon's example of a 6"x12" plate), machining, and delivery to your door. They'll be CNC machined, radiused edges on the driver opening, deburred, and drilled and tapped for mounting hardware.

I may not be able to contribute around here as far as design of the loudspeakers, but maybe I can contribute as far as helping with construction. I know how hard it can be sometimes, trying to find somebody to do something you're not capable of doing yourself!

:T

[cjd]

Wow Brian, if you can supply that would rock. If I go in-wall I may be interested in full-baffle sized pieces. Would you be able to countersink if that were called for?

The goal I would have in mind is a wall-plate which would get backed by MDF or ply, but giving you the aluminum around the outside edges to make the actual securing to the wall process simpler.

C

[Brian C.]

Countersink? Absolutely!

Want your name engraved in the plates? Can do. :B

I can do everything short of 3D machining (4 and 5-axis milling). We just don't have that capability (yet).

I keep .250" aluminum in stock, in 13"x14", 15"x30", and 24"x24". I can get any special sizes I need, or cut what I need from available stock.

:T

[Brian Bunge]

Brian,

Just out of curiosity, what about a brushed aluminum finish?

[joecarrow]

Wow, are you serious? It's awesome that you would offer to help like this.

I was playing around with Emachineshop last night, and I was able to get simple baffle cutouts for around $15... in quantities of 25. In quantities of 2, it was about $75 each. Oh, and the lead time was around a month. Your offer of $25 is extremely generous, considering the designs I was playing with didn't have any countersinking or anything.

I don't know if doing a huge pile of the same thing will be significantly easier for you than doing a small handful, but I'm guessing not. Shipping to a ton of different addresses is kind of a pain. Maybe if someone comes up with a slick design that works far better with this baffle method than with wood, then you could prototype it for the first couple of speakers, and then we could put together a group buy to get some economy of scale.

What do you think? A small satellite speaker? A plate for a dedicated mid in a 3-way? Tang bands? Aurasounds? Something else?

I can't even fit another speaker in my apartment, and this has me excited.

[Brian C.]

Brian,

Just out of curiosity, what about a brushed aluminum finish?

Actually, that's pretty much the way they would come. Most, if not all of our aluminum comes with a brushed or satin finish, showing "grain" (yes, aluminum has grain, too! ).

Here's a sample... this piece has been kicking around our shop for a while, so any blemishes are not indicative of what you'd be getting. I just quickly buffed it with a piece of medium scotchbrite...

Image not available


And to Joe...

Of course, anything in quantity becomes cheaper, but I don't know if I could really do it any cheaper than what I've quoted. Can I do them in quantity? Sure! Lead times would, of course, be a bit longer.

[joecarrow]

Brian,

Of course I wouldn't expect you to do it any cheaper- your time isn't free! As it is, you've offered quite a bargain. I guess I was thinking more about if a project came along that was at least as popular as anything in the Mission Accomplished section- some shops would be glad to do a batch of 200, and able to drop the cost a lot if they're used to that kind of thing. I guess at that point it gets really specific about what machining needs to be done, and how much material is used.

I think I'm getting ahead of myself.