Discussion on what materials to build speakers out of

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Okanagan, I have a someone looking for some decent no-void for me, but in the end the price will dictate what I can end up using.

When I worked in building supplies a short while back, the decent stuff was a more than I cared to pay, especially since it would be just a single sheet. Seems everyone up here just stocks what is needed to build houses and make kitchen cabinets.

I really hate the voids (black spots, gaps) that will happen when I roundover the side baffles (cosmetic). I'd rather not use edge veneer as that would be a new experience for me and I do want a roundover (full roundover inside the throats).


Thinking...

I suppose I could waste a bit of wood getting a cut that has no voids along the whole line, but the dark spots will probably still bother me. Mabye my expectations of no-void are too high. But hey, this is cosmetics, no point being disapointed in the look before I even start. Hence the MDF and gloss white, at least it would have high WAF and hide then.
 
frugal-phile™
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The point of void free isn't cosmetics but sonics. Even shop grade BB has potential cosmetic issues. Even spending 3x as much on architectural grade doesn't guarantee the cosmetics (althou it goes a long wayd)

Can't someone order you in some (it is going to take more than 1 sheet to fo Calhoun). Given driver cost & your time to do the boxes, it seems a shame to compromise by using MDF,

Pine would be interesting thou -- and you said it was laminated, so that should help as far as the usual problems with solid go.

As to doing a round-over on anything but the external edges, i'd be hesitant. Part of the design is the discontinuities.

dave
 
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There's another problem with voids that all speaker builders should be aware of: there might be loose material in the void that will vibrate and buzz along with your music.
Use the MDF already.
NEVER in a million years would I ever use solid wood to build a speaker. Probably the worst choice ever.
 
I used Project pine for some cabinets, it is more than MDF ($20 for a 16"x4' piece vs $30 for a 4x8 3/4") but there is a large batch to pick some interesting grain patterns out of and minimize the knots.

Because of the lamination though, cutting with the grain is more of a chore than ply.

If a roundover on the inside edge isnt recommended, is a small bevel a good compromise?
 
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MJL21193 said:
solid wood to build a speaker. Probably the worst choice ever.

Not so. Scott has built some fantastic speakers of solid fir, GM has used pine boards (as have a number of others on the FR Forum). At least a few hi-end commercial speakers are made of solid.

It is true that solid wood requires the most care & attention when building. In this case he is talking laminated pine boards not solid.

MDF just seems to suck the life out od a speaker. If you have to at least use medite (HDF)

dave
 

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frugal-phile™
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ruerose said:
If a roundover on the inside edge isnt recommended, is a small bevel a good compromise?

One of the intentional design features of this kind of cabinet are the sharp corners. The deflector could be made of a single piece, bur the only place wher you might be able to put a bevel is the edge at the transition from the straight section of the port to the bell.

dave
 
Solid wood worst choice for speakers?!? I think not. It depends on your material knowledge, but anything with a tight grain and high stiffness / weight ratio should beat MDF hands down. Look at Terry Cain's creations -I suppose the now pretty distant original inspiration for Calhoun. Fir and pine, if treated right according to Terry, are amongst the best materials for horns or their variations, so long as the moisture is low. Love that idea. GMs pine came from an old barn door I believe, ~150 years old if memory serves, and had similar properties to aluminium after aging for that time.

Roundovers go somewhat against the design intentions, which is to deliberately have the sharp edges, but as Dave says, if you want to, the the transition of the initial port to the bell-flare is the place to put them.
 
I just about made the Calhoun's with the pine board. The boards (pine shelving) at Home Depot showed enough twisting that I thought the better of it. If I had enough clamps it would have been fine but I was using a finish nailer and that doesn't provide enough strength to suck the two pieces together so I made it from Maple plywood and the horns from MDF. The horns were made of MDF because it comes as a 3/4" board where as the ply is now metric and measures 23/32"

It was all done in modules. The horns and inside cabinets were made ahead of time then simply slapped the sides on.

EDITED: Overstated the obvious:)
 
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Quote: "Solid wood is a problem when it comes to wide panels, the expansion and contraction may cause cracking and joints to open up"

pinkmouse: My hat's off you, once again the voice of reason.
Is this a DIY forum? Yes, solid wood can be used to build speakers, but it must at a stable moisture content. How does the average DIY guy know if his laminated spruce panel is at 4% moisture? I'm pretty sure a reliable moisture meter is no in the DIY toolbox. Also solid wood should be sealed on all sides to maintain the moisture content. It's more expensive. Three strikes, you're out.
 
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I don't mean to offend you, it's just using solid wood ( even laminated ) is not a very good choice. It's sonic properties are not consistant, it's prone to warpage and movement.
Do your self a favour and do a Google search for: "use solid wood for speakers" and read some of the results. My bet is that the result will not be encouraging.
 
MJ -do yourself a favour and read everything Terry Cain ever wrote on the subject of solid wood and speaker cabinets. You might find it of interest. Admittedly TC was the God of materials, but his lessons are worth learning. GM's remarks on the subject too are most enlightening. Solid woods offer many potential benefits -like cabinet design, it's a matter of learning what they can offer, and utilising them correctly.

Example: a BIB could be usefully constructed using solid walnut side-panels, pine internal baffle and rear, and alder front. We use the different properties of the materials to suit what we want each to do. For man-made, change that to BB ply for the sides, particle-board for the inner and rear baffles, and a lamination of MDF and ply for the front baffle. It won't be as good as the solid wood though. Or look as good come to that. True, you have to know how to work with the solid woods, but that's no great trial -it's a fascinating subject I'm working on at the moment.
 
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