Very quick question, I noticed that a lot of people use Baltic Birch or MDF in speaker construction. Is there a particular advantage in this over, say solid Oak or Cherry other than cost?
I'm contemplating a build using the above Cherry/Oak and was wondering if it would put me at a disadvantage?
I'm contemplating a build using the above Cherry/Oak and was wondering if it would put me at a disadvantage?
Individuals use MDF for its "dead" sounding nature, the low cost, ease of machining, sawing, shaping, et cetera. The downsides, its fumes & sawdust aren't good for ya', don't dare get the stuff wet...or high humidity,
Solid wood planks have that shrinkage, warping issue. If the stuff is too green, as it dries it will warp, shrink & possibly crack. It's a stability issue. Further, there is the resonant differences with solid boards. A lot of the resonance issues can be mitigated with reinforcement bracing, but often times some tend to go a little crazy with bracing...making for an unwieldy heavy enclosure.
Plywood has the air-void issue...finding fully void free plies within plywood is not cheap by any means. Plywood is much more stable than the likes of solid boards, not at all prone to warpage. Some times an individual will fashion a solid board enclosure to find six months down the road it unexpectedly cracks as it "dries out".
-------------------------------------------------------Rick...........
Solid wood planks have that shrinkage, warping issue. If the stuff is too green, as it dries it will warp, shrink & possibly crack. It's a stability issue. Further, there is the resonant differences with solid boards. A lot of the resonance issues can be mitigated with reinforcement bracing, but often times some tend to go a little crazy with bracing...making for an unwieldy heavy enclosure.
Plywood has the air-void issue...finding fully void free plies within plywood is not cheap by any means. Plywood is much more stable than the likes of solid boards, not at all prone to warpage. Some times an individual will fashion a solid board enclosure to find six months down the road it unexpectedly cracks as it "dries out".
-------------------------------------------------------Rick...........
As Richard said solid board enclosure is good if you master the classic furniture manufacturing (what is less and less usual these days). I have some (but made from ready large boards from the likes as IKEA with preferences for the least or NO wooden knots) and they are enough stable for a few years on. Exception of the back & front panels that were made of ply because they were larger than the stock planks or shelves.
The pro enclosures are almost all made of ply.
IKEA solid wood worktops
WISA-Spruce plywood
The pro enclosures are almost all made of ply.
IKEA solid wood worktops
WISA-Spruce plywood
Baltic birch or similar material makes the best practical speaker cabinets so long as it is braced properly.
I have used oak veneer and have seen some enclosures that used oak / maple wainscot on top of Baltic birch. You can even use some exotic wood flooring for the sides / top /bottom of the enclosure and biscuit joined solid wood for the front. You do take a chance of wood shrinkage / cracking as the solid woods age depending on the humidity or lack there of.
If you decide to use a solid wood on top of Baltic birch DO NOT USE regular wood glue as it has a tendency to creep--use a furniture grade epoxy such as Unibond 800.
I have used oak veneer and have seen some enclosures that used oak / maple wainscot on top of Baltic birch. You can even use some exotic wood flooring for the sides / top /bottom of the enclosure and biscuit joined solid wood for the front. You do take a chance of wood shrinkage / cracking as the solid woods age depending on the humidity or lack there of.
If you decide to use a solid wood on top of Baltic birch DO NOT USE regular wood glue as it has a tendency to creep--use a furniture grade epoxy such as Unibond 800.
+1
One can make a good cabinet out of solid, but you need to know what you are doing and execution is important. Solid wood can be VERY beautiful. I am currently listening to a set of solid western cedar prototypes.
MDF is cheap. It is easy to machine. Should be way down the list in terms of being desirable for a speaker box.
Of the commonly available "wood" sheet materials, the best is probably stranded bamboo plywood. Much more expensive than good ply.
dave
bamboo
Hi Dave,
Bamboo, and bamboo ply are like the "new scene". What is it about this material that makes it superior ?
Thanks in advance, Scott L.
Hi Dave,
Bamboo, and bamboo ply are like the "new scene". What is it about this material that makes it superior ?
Thanks in advance, Scott L.
Very stiff. Very hard (so hard to ding). Very pretty (no need for anything but clear finish).
dave
Grows faster than any tree - hardly yet an endangered species - but then again, considering the distances travelled and total energy expended from harvest to end user, not a tiny ecological footprint
With the globalized economy, what is anymore?
As Dave says, can make for gorgeous enclosures
With the globalized economy, what is anymore?
As Dave says, can make for gorgeous enclosures
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I once made a pair of speaker cabinets from veneered chipboard.
I used them on a mobile disco.
I used a trailer for the disco wit ha rain sheet over it.
One night I did a gig and it was pouring down with rain.
I rolled speakers into the gig then back out again at the end when it was still raining.
The next day IO looked at the speakers and the rain had swollen part of the panels.
The chipboard had become crumbly where it had got wet.
I now use cheapish plywood and haven't had any problems with rain.
I used them on a mobile disco.
I used a trailer for the disco wit ha rain sheet over it.
One night I did a gig and it was pouring down with rain.
I rolled speakers into the gig then back out again at the end when it was still raining.
The next day IO looked at the speakers and the rain had swollen part of the panels.
The chipboard had become crumbly where it had got wet.
I now use cheapish plywood and haven't had any problems with rain.
Well, as I say, the cabinets would be made by a professional carpenter with more experience than he'd thank me for mentioning. So to summarise, would I be correct in saying there would be no reason why I cant use solid oak/maple/cherry instead of MDF/baltic birch provided its not fresh wood (dried) and the person using it knows what they're doing ?
The movement of solid wood for speaker enclosures (stiff, rigid, airtight,...) is sufficiently serious that I find it hard to believe that many professional carpenters would consider doing it. You seem to know a professional carpenter, what does he think about the idea? Now I can see the attraction of the challenge but if your main interest is a speaker rather than an experiment to see how long a solid wood speaker enclosure might last before it fails then solid wood is not going to be a reasonable engineering decision.
Tables and other furniture have been made out of solid wood for centuries, and although I have seen a few that have cracked, the majority is still OK. One has to allow for movement with changes in humidity, although I do suppose that most of us don't haul our speakers out into rain or snow, but rather keep them indoors in a fairly well controlled environment.
Keeping away from crossgrain joints is part of the trick. Wood moves mostly along crossgrain, so imagine wrapping the sides and top/bottom out of a long piece of board, and then allowing for some movement with screwed joints for front and back, should do the trick, if one really want to build from solid or laminated wood. OTOH - if you're looking for some fancy wood, that might quickly become more expensive than the drivers needed
Keeping away from crossgrain joints is part of the trick. Wood moves mostly along crossgrain, so imagine wrapping the sides and top/bottom out of a long piece of board, and then allowing for some movement with screwed joints for front and back, should do the trick, if one really want to build from solid or laminated wood. OTOH - if you're looking for some fancy wood, that might quickly become more expensive than the drivers needed
Execution is key when using solid wood. We can't add a loose panel, a common used practice. Tho a floating front baffle made of solid wood would be no problem.
With mdf use an art grade shelac or something like Zinsser B-I-N and seal everything including all drill holes prior to assembly. Last I priced Zinsser it was something like $43/gal. This added expense may prod you to use BB from the get go. Much harder to get and KEEP that showroom finish with mdf.
With mdf use an art grade shelac or something like Zinsser B-I-N and seal everything including all drill holes prior to assembly. Last I priced Zinsser it was something like $43/gal. This added expense may prod you to use BB from the get go. Much harder to get and KEEP that showroom finish with mdf.
Since you've got a tame carpenter at hand I'd suggest making the box from void-free ply (marine or birch) and have him veneer it.
For some reason vibrations don't like travelling through dissimilar materials so I'd use MDF for the bracing. Ideally fixed to the box with a glue that retains some flexibility after setting.
For some reason vibrations don't like travelling through dissimilar materials so I'd use MDF for the bracing. Ideally fixed to the box with a glue that retains some flexibility after setting.
...but, bracing should be as stiff as possible and MDF is anything but. It would be better to just use BB ply throughout. A well braced box made from BB will have panel resonance high enough not to be an issue. Coupling the driver to the back of the enclosure with a dowel or as part of the bracing will negate the vibrations from the driver basket, big "bang for the buck".
Material............................Stiffness (Modulus of E)...............Damping Factor
Laminated Bamboo Lumber....1,500,000 psi..............................0.2 (good damping)
Baltic Birch Plywood..............1,100,000 psi..............................0.04 (little damping)
MDF.......................................450,000 psi..............................0.02 (little damping)
Laminated Bamboo Lumber....1,500,000 psi..............................0.2 (good damping)
Baltic Birch Plywood..............1,100,000 psi..............................0.04 (little damping)
MDF.......................................450,000 psi..............................0.02 (little damping)
I can't think of a worse thing to do, vibrations will simply be transmitted to the cabinet in a way no damping can deaden, it needs to be decoupled not coupled.
I have searched this recently and it seems that except for very small enclosures where all the variables are much limited, it has to be MDF for sound quality reasons only....
Footnote, why can't we buy HDF, high density fibre board?????, that would seem even better??
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