I have some free time today, so I wanted to whip up a pair of speakers. I have a tendency to leave projects in an unfinished state for a long time once they are good enough for listening. Although I have some good plywood, I'm thinking why not use some of the beautiful hardwood I have. Once I get the panels planed and smooth I'll still have at least 1" thick panels. Using GM's little MLTL design for the FE127E , the panels are small and narrow (interior dimensions are 4.58"x7.43"x22.38"). I thought I could get away with using hardwood. It's well dried and I plan to insert the pipe into routed out top and bottom caps, since I may use them upside down on top of an entertainment center or on my desktop and they'll be stable upside down or right side up. I'll call them my AC/DC pipes.
Is this a good idea for a one day start to fully finished project, or would there be some problem with hardwood on a small MLTL?
On the topic of hardwoods, I also have some very dense hardwood too. This stuff is so dense you can't drive a nail through it, it eats router bits for lunch, and sand paper has almost no effect. It's so rigid and heavy that I was thinking it might be good for building an RLH. Is hardwood a good idea for horns or should I just save it for making speaker baffles and cab tops?
Is this a good idea for a one day start to fully finished project, or would there be some problem with hardwood on a small MLTL?
On the topic of hardwoods, I also have some very dense hardwood too. This stuff is so dense you can't drive a nail through it, it eats router bits for lunch, and sand paper has almost no effect. It's so rigid and heavy that I was thinking it might be good for building an RLH. Is hardwood a good idea for horns or should I just save it for making speaker baffles and cab tops?
Your call really. It rather depends on if you like it's resonant character, which until you build it would be difficult to ascertain. If you're not going to be generating huge SPLs, it might be worth a shot. It'll sound different to ply, and from MDF / HDF, which are much less resonant than either as a rule. Lots of peole swear by it -I know someone who built a big transmission line from 30mm hardwood and loved it, and Terry Cain's speakers have, shall we say, a loyal following, but some don't favour its signiture, which is fair enough. (It's comfy on this fence you know 
Scott
Scott
My thought process is that the thick wood in such small dimensions will be quite dead and I'm hoping the resonant frequency of the pipe is well below that of the panels and that the stuffing damps anything near the RF of the wood. From the looks of TC's designs, they appear to take advantage of resonances and the construction materials would have a huge impact. No way I'd build an Abby clone out of MDF.
I really don't think splitting or warping will be an issue due to the small sizes of the panels ensuring strong structural support. Temperature is a non-factor down here with 60-75 F year-round. I'll put some poly on the inside before sealing it up and rub some oil on the outside to fight against humidity. Plus they won't get any direct sunlight.
Ease of construction strongly favors the hardwood to me. Cut the pieces and glue the pipe. Butt joints should be much stronger than with plywood. Cut driver and port holes. Do some routing and sanding. Mount the driver which will be hard wired. Add some polyfill and glue the top and bottom caps. Rub on some Danish oil and they're totally ready with a beautiful finish. No veneering, nice rounded exposed edges, no ugly tubes in the port, and easily a 1 day job with half of it spent waiting on the glue.
I really don't think splitting or warping will be an issue due to the small sizes of the panels ensuring strong structural support. Temperature is a non-factor down here with 60-75 F year-round. I'll put some poly on the inside before sealing it up and rub some oil on the outside to fight against humidity. Plus they won't get any direct sunlight.
Ease of construction strongly favors the hardwood to me. Cut the pieces and glue the pipe. Butt joints should be much stronger than with plywood. Cut driver and port holes. Do some routing and sanding. Mount the driver which will be hard wired. Add some polyfill and glue the top and bottom caps. Rub on some Danish oil and they're totally ready with a beautiful finish. No veneering, nice rounded exposed edges, no ugly tubes in the port, and easily a 1 day job with half of it spent waiting on the glue.
audio-kraut said:add a couple of strings in front of the driver and tune it to your liking. Thats what I think of solid wood for speakers. As far as my opinion matters.
I'm using a totally different type of wood than what is available to you way up there and with the small dimensions I doubt that my cabs will be singing at all, so I can forget about the strings on this pair.
contrary to opinions of some "highenders" a loudspeaker to me is not a musical instrument, but a music reproducing instrument, and as such in the same category as an amp or a cd player. Any resonances produced by this reproducer is frowned upon by me and considered an unwelcome alteration and deviation from the goal of reproducing as neutral as possible, as true to the source as possible.
So - if you consider for beauty sake to use this material that usually does not behave in a neutral manner - go ahead, but don't complain afterwards.
So - if you consider for beauty sake to use this material that usually does not behave in a neutral manner - go ahead, but don't complain afterwards.
Hmm. I can see the liking for speakers that have been designed in the same fashion as a musical instrument; they're lovely for, say, classical and jazz etc, though they won't be the most accurate or versatile. Have you seen Bosendofor's new models, with huge soundboards like one of their pianos energised by reflex ports on the sides for example? I've heard a few speakers designed like instruments, and enjoyed them with certain material, though it's not how I go about building my own cabinets. I do like to blast Iron Maiden sometimes, which doesn't suit something that's been designed like a chello too well.
On the up side, at least it's not a full-scale TQWT built from -wait for it: unfinished pine as an aquaintence of mine did a few weeks ago.
Worse still, it was to the infamous So=0 Voigt design (he must be be spinning in his grave to be associated with such a rotten cabinet type).
Oh listen. Is that the sound of pine splitting when our rotten British summer kicks in?
On the up side, at least it's not a full-scale TQWT built from -wait for it: unfinished pine as an aquaintence of mine did a few weeks ago.
Worse still, it was to the infamous So=0 Voigt design (he must be be spinning in his grave to be associated with such a rotten cabinet type). Oh listen. Is that the sound of pine splitting when our rotten British summer kicks in?
One thing I would look out for with hardwood construction is shrinkage/expansion. I built my MLTL's out of baltic birch plywood and walnut. The drivers are mounted on the walnut. I built them in Iowa and then brought them down to North Carolina and I have to say the drivers fit quite a bit tighter now then when I built them.. I'm a little worried they will expand more over the summer, we'll see. Nothing a little sand paper can't solve. I would say go for it though, and I don't see any reason not to brace it, I've certainly got some shelf braces in my MLTL.
Joe
Joe
johninCR said:
Perfectly acceptable, and well-worth the effort in my view, so long as you take into account their affect on the internal volume (very small, but I thought I'd best mention it.) I believe Bob Brines uses extensive bracing in his MLTL designs, and they are very well regarded -they measure superbly, and his cabinets have a reputation of being acoustically as dead as you're ever likely to get.
OK, we all know (mostly) that a speaker is not a musical instrument. That said, musical instruments are resonant because the wood is worked very thin and allowed to vibrate as much as possible. MDF will work for a guitar just fine if sufficiently thin. In fact, Martin made an MDF model for a while. Might not sound that great, but it does work. A speaker cabinet is never .09" thick.
My point is MDF is not 'non-resonant'. Sure, the DF is a bit higher than solid woods for the most part, but then again real wood usually has a higher young's modulus. Going slightly thicker with solid wood and adding some damping gook will work well enough in the real world. Some lumber has both decent DF and high modulus. Rock maple comes to mind. These are just materials. Address and design around their properties rationally and it will work out.
The real problem with solid wood is cracking and shrinkage/expansion with humidity changes.
I guess I sort of already answered this.
My point is MDF is not 'non-resonant'. Sure, the DF is a bit higher than solid woods for the most part, but then again real wood usually has a higher young's modulus. Going slightly thicker with solid wood and adding some damping gook will work well enough in the real world. Some lumber has both decent DF and high modulus. Rock maple comes to mind. These are just materials. Address and design around their properties rationally and it will work out.
The real problem with solid wood is cracking and shrinkage/expansion with humidity changes.
I guess I sort of already answered this.
GreGb is right. Man, it's like wooden aliens visit audiophiles homes and install sawdust nigtmares.
Hardwood? What hardwood? What grain, quartered, vertical sawn, flitch cut flat grain what? It's all different.
MDF? Rangerboard? Common Home Depot consumer closet shelf board?
Resonance patterns are totally dependant upon sizes of panels, joinery and structures. I'd take a softwood speaker made by a craftsman vs a composite speaker made by a common woodbiter any ole day.
Joinery, overall design, panel size and grain direction have to be addressed to fully evaluate materiials. Then on to moisture ccontent and wights and stiffness. Anyone check their mdf's moisture content? Who knows hown much difference mdf's ridgidity changes per % of moisture change?
Take GM's solid souther pine 1354a project. 50 year old barn board that had endured time and stabilized, densified. Probably the stiffness to weight of aluminum (with the grain). Of course that will sound fine. A dense softwood better than MDF? By a mile if you ask me.
Absorbing resonance, and redirecting it, by ridgid reflection need to be better understood. Throwing mdf and energy absorption at the problem is ignoring the problem.
The right material to build speakers out of is the one you understand and are able to manipulate best.
TC
Hardwood? What hardwood? What grain, quartered, vertical sawn, flitch cut flat grain what? It's all different.
MDF? Rangerboard? Common Home Depot consumer closet shelf board?
Resonance patterns are totally dependant upon sizes of panels, joinery and structures. I'd take a softwood speaker made by a craftsman vs a composite speaker made by a common woodbiter any ole day.
Joinery, overall design, panel size and grain direction have to be addressed to fully evaluate materiials. Then on to moisture ccontent and wights and stiffness. Anyone check their mdf's moisture content? Who knows hown much difference mdf's ridgidity changes per % of moisture change?
Take GM's solid souther pine 1354a project. 50 year old barn board that had endured time and stabilized, densified. Probably the stiffness to weight of aluminum (with the grain). Of course that will sound fine. A dense softwood better than MDF? By a mile if you ask me.
Absorbing resonance, and redirecting it, by ridgid reflection need to be better understood. Throwing mdf and energy absorption at the problem is ignoring the problem.
The right material to build speakers out of is the one you understand and are able to manipulate best.
TC
TC,
I'm not a craftsman, but this is pretty simple and I have a table saw, planer and router. I've had the wood for about 6 months in a dry area. With a maximum interior dimension of approx 22"x7.5" it should be fine. The wood has really beautiful grain, so I guess it's half sawn, which isn't optimal, but I'll take the risk. Joinery will be just butt joints, but with a planer to make all edges perfect, I should be fine.
Thanks for the encouragement. Good wood is about the same price as good plywood down here, so I scoop up pretty stuff directly at the mill when I have a chance. Then I let it dry through at least one dry season and wet season to get it stabilized before use. No cracks in anything yet (fingers crossed).
John
I'm not a craftsman, but this is pretty simple and I have a table saw, planer and router. I've had the wood for about 6 months in a dry area. With a maximum interior dimension of approx 22"x7.5" it should be fine. The wood has really beautiful grain, so I guess it's half sawn, which isn't optimal, but I'll take the risk. Joinery will be just butt joints, but with a planer to make all edges perfect, I should be fine.
Thanks for the encouragement. Good wood is about the same price as good plywood down here, so I scoop up pretty stuff directly at the mill when I have a chance. Then I let it dry through at least one dry season and wet season to get it stabilized before use. No cracks in anything yet (fingers crossed).
John
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