Qs about speaker baffles ????? Need help

[Tele]

Hi everyone,

I would like to make an new baffle for a 2x10" amp to covert it to a 1x12". What kind of wood is recommended and why????

Andy

[Donny Hinson]

I recommend three-quarter inch void free plywood, or lumbercore. You need at least this thickness to prevent warping and provide proper support, so as to not warp the speaker basket. Whatever you use, it must be SOLID (void-free). Open spaces between plys, or between boards will cause buzzing and rattling. Tempered hardboard or particle board is not recommended for baffles, but may be used for an enclosure.

Fasten the speaker to the baffle with sheet-metal screws (#8), or with bolts (machine screws) and "T"-nuts. Never use wood screws to fasten a speaker to a baffle.<FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by Donny Hinson on 31 May 2000 at 05:23 PM.]</p></FONT>

[Jack Stoner]

Donny is correct. Good quality 3/4" (whatever that is is mm) plywood is the preferred material and what is used in almost every amp I've seen.

Guten Tag

[Dave Zirbel]

How does the thickness of the baffle affect the tone?

Dave

[Dave Boothroyd]

Put it this way Dave, The speaker cone has to move the air to make sound. If the speaker frame can move, everytime the cone moves forward, the speaker will move back.So it will not move so much air.
Unless you make the baffle from 300mm osmium, reinforced with girders, it is bound to flex slightly, and it will flex more at some frequencies than others, so some frequencies will be cut more than others.
That is what we in the trade call "altering the tone"!

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Cheers!

[Mark Herrick]

Why are wood screws not good for attaching the speaker to the baffle?

[Donny Hinson]

Mark,

Wood screws are tapered. This taper means that when the screw is backed off only slightly, much of the "holding power" is gone. Sheet metal screws are tapered only at the point, so there is no tendency to "fall out of the hole" as a wood screw might do. Also, metal screws are made from tougher metal than wood screws, lessening chances of "stripping" the head.

[Hamilton Barnard]

3/4" board won't fit in any Fender combo that I own (if that's what you are talking about).

I used 1/2" MDF (medium density fiberboard) in my Vibroverb and Princeton Reverb amps. Fender used both MDF and plywood.

[Jack Stoner]

I had an AB768 model Fender Twin Reverb. I replaced the two original 12" JBL D120F's with a 15" JBL K130. The mounting board that was in it was 3/4" plywood and I used 3/4" plywood for the new mounting board. I bought some Fender grill cloth and reinstalled the Fender logo on the front and it looked original.

[Joe E]

I beleive Fender was using 5/8 board for the baffles. I don't think you would hear a great difference in plywood vs. particle board on an open back fender.

Wood screws are fine as long as they are pan heads. Better yet though would be T-nuts.

I also suggest that you round off or bull nose the edge of the speaker hole. It does not need to be much. Just enough to eliminate sound waves from sharp refractions.

I also have plenty of Original Fender grill cloth if anyone is interested. I've been selling pieces big enough to cover twins for 25 bucks plus shipping. Don't take apart that original baffle for the grill cloth, you'll want to preserve that for putting it back in the amp.

I shipped a piece to Ricky Davis for his conversion.

Joe

[Robert Parent]

Baltic Birch plywood works well. It tends to resist warping (contains more layers than standard plywood) and most of it is void free. I have build several cabinets using it with good results. Some of the better enclosure manufactures also use it.

I bolt the speakers using t-nuts. Fast, strong, cheap and with a little lock-tite the screws have yet to come loose.