Baffles: Real Wood vs MDF vs Layering

[Monroe]

I'm just finishing up with my Odin Mk3 MTM Case, and have decided to redo the baffle before i install it (it was in 3/4 MDF and I wasn't very happy with the thickness or the precision of the circles).

I was considering using a 1 inch thick real wood baffle, so that the roundover-edges would have some nice grain and be stainable (MDF rounds ok but looks like crap next to rosewood veneer, unless i'm doing something wrong...)

BUT: someone mentioned that using a sold wood baffle would negativly effect the sound (resonance?). Is this the case?

What is an ideal baffle, given that I dont want to have exposed MDF roundover-edges if possible. (Alternately, if I must have these edges, is there a good way to give MDF a solid black color? What sort of point will sit on it? - it just soaks everything up :P)


Thanks!

[till]

those people who claim real wood sounds worse than MDF never tried or did it wrong. I suspect they say so because say managed to buil something box like from MDF once in life.

Go with the real wood if you can do, glue it from some not to big blocks together.

Else use high quality plywood.

Problems with the wood will occure if you use it too thin.

[454Casull]

Mmm... You can use a baffle that's 1/2 solid wood, 1/2 MDF. Cut the rear layer (MDF) so that it fits into the 4 side walls (when the rest of the enclosure is assembled) without any gaps, and cut the front layer so that it's flush with the outside of the 4 side walls. Then your baffle will be relatively sonically inert, and look good at the same time.

[Wright]

I don't understand the problem with using veneer. Unless the veneer is particularly brittle you can usually veneer over the roundover as well, so it looks like a solid piece of wood. I have heard it stated many many times from many knowledgable sources that using real wood as opposed to mdf with create more audible colorations, so I would be hesitant to try it. Alternatively, if you just want a black baffle you can paint the mdf black, but you should use several coats of primer or sanding sealer first so the mdf won't just soak it up.

[Timn8ter]

Real wood is great but be prepared for a lot of prep work. I used some 4/4 Lacewood (each piece was 5" wide). The planks had to be planed, then glued together so I ended up with a 9" plank just a little over 3/4" thick.

[cfbuck]

Munroe,

I concur with 454Casull. I have been to see Jim Salk's speakers (www.salksound.com), who I think was influenced by Dave Ellis (www.ellisaudio.com) who uses solid wood baffles. In both cases, the inner baffle is 3/4" MDF. The outer shell is then glued with NoNails or any adhesive which has some flexibility to it so that the wood, when it moves with moisture absorption can expand while the MDF remains relatively the unchanged. Jim Salk applies a 1" x 3/8" hardwood strip around the outside, mitred at the corners. It has a 3/8" roundover. Then he sizes the hardwood baffle so that it fits just inside the roundover. He then rabbets the edge of the hardwood so that it will drop inside the edge strip but no quite contact the MDF baffle. He rounds over the edge of the baffle with a 3/8" roundover, thus producing a modified 3/4" roundover. Then he glues the baffle to the MDF with NoNails.

I have made 5 MBOW1 speakers using Salk's method but they have not yet gone through the winter/dry-summer/humid cycles to see if the hardwood baffles withstand the changes in humidity and stay glued to the MDF inner baffle. But Jim's speakers have done so over at least 2 years without problems. Check out his website.

Fred

[Chris8sirhC]

As far as I know the more, different, layers you have the better. Just make sure you have the inner baffle cut away enough to let the back of the driver "breathe." I'm pretty sure the theory behind this is, one: added mass, and two: the different materials have differend resonance frequencies, so they sorta block resonance frequencies for eachother. You could always take it to the extreeme and make a front baffle thats almost 4'' thick and made of 4 different materials.....

[ultrachrome]

I'm putting 4/4 African Mahogany on my Ellis 1801. It looks nice but it's a lot of work. Remember you need to veneer first then put the hardwood on last so the edge of the hardwood is flush with the veneer surface. Clamping it without scarring the solid wood baffle and the veneer on the back was a little unweildy. And when you glue it, baffle side down (so the glue doesn't get on the veneer), the enclosure skates around as you tighten the clamps.

Be careful about chip out when trimming it to fit. The piece you glue over your old baffle shouldn't be more than an 1/8" oversized. I didn't heed this advice and I chipped a corner that I hopefully can fix with the piece that chipped off.

I don't know if I will use hardwood again on a speaker this size when veneering is so easy.

[Timn8ter]

the enclosure skates around as you tighten the clamps

Four 1/4" dowels will line up the baffle for you while you clamp.

[RHosch]

One material does not block the resonant frequency of another.

Adding mass may or may not be a good thing, depending on the resonant frequency obtained as a result.

Adding stiffness is almost always a good thing, but might drive a resonance up into a critical band (though amplitude at resonance will be lowered).

There is nothing in MDF that makes it a superior material for speaker enclosures other than (1) easier to predict final stiffness and resonances and (2) easy of workability and dimensional stability. It doesn't "sound" better than natural hardwood.

Damping is beneficial for fullrange or monitor type enclosres (much less so for sub enclosures). Mass added that has a high hysteresis damping can lower the amplitude of resonances.