Hardwood for speakers??

[bobhowell]

I went to a local hardwood store for a current project this week and was floored by the beautiful, wide, straight,4/4 boards available. Cherry, 11" wide and 9' long, 100% usable for $45. Jatoba, (Brazillian Cherry) 13" wide and 9' long, $40. Prices were great and the best wood I have seen for table tops. But how about for speakers? Everybody uses MDF but I see little about solid wood. This wood is all finished 3/4 thick for the cabinet tradesmen. Their regular customers don't want the figured wood because it is more trouble to work. They have several thousand bf of curly soft maple, 4-8" wide for $1.95 bf.; beautiful!!

I think the bad housing market is affecting the price and quality available. I am in Atlanta, but this is nationwide, so you might want to check your local hardwood store.

I am new to speaker building, so tell me what works. I just built Zaph's BAMTM out of 5/4 poplar. because I had it. Sounds great!!

Jatoba is the widest available and is $3.53/ bf. It is very dense, but is that good? Poplar and basswood are softer but available in 9-11" and 5/4-8/4. thick.

What works??

Thanks,

Bob

[Amphiprion]

Do not do it! Unless it is just for a baffle and the baffle is 'floating'.

I made the mistake of using a solid oak baffle on an otherwise MDF cabinet. 6 months later I had a cabinet that had split at the seams as the oak had expanded across its width.

Some woods are more dimensionally stable. I imagine poplar is one, while oak is one of the worse. But I would only ever use them for a baffle where the baffle is not glued to the cabinet - 'float' it by using a sealing compound (rope caulk for examply) between the box and the baffle and only secure the baffle at the four corner points (sort of like the Parts Express B-REX baffle system on their cabinets).

I agree though, it is beautiful. Sometimes I go to my local hardwood store and just find a beautiful board and buy it. I've got an 8" wide 2.5' long 4/4 piece of padauk that a friend helped me surface plane and joint. It's becoming a baffle or an electronics enclosure one of these days.

Also remember that veneer is a 'greener' alternative. There's no need for a 4/4 thick piece of flame maple for a speaker cabinet when you can use the same material in veneer over MDF format. Save the special and/or endangered woods.

[ThomasW]

We answer this question often....

We're not making musical instruments (just say no to resonances when/if possible). So we want material that has a high density and equally important the same density throughout the panel.

[bobhowell]

Seems like folks are having problems with splits. I know how to deal with that. Just sides and top and bottom of hardwood, with only end grain connecting to end grain, and MDF for front and back. Poplar and basswood are cheap and available in clear, wide, boards. I think a softer, thick, board like the 1"(5/4) thick poplar I used for the BAMTM would have more sound damping qualities than MDF.

I've made about 15 jewelry boxes for my daughters and nieces over the years, using these principals. I am confident in using them.

Jatoba is hard and might produce resonance of some sort. I wonder if 5/4 thickness might deal with this. It is a lot more exciting than Basswood and not much more expensive.

I have no problem with the environmental angle. Its ALL wood.

I Hate working with MDF. Making the baffles for BAMTM was a pain but about the only way, so I used it, and plywood for the back. I want to know what issues to consider when selecting a hardwood, so I can make quality speakers.

Also, in 18 years of making the rounds of hardwood stores, I saw extraordinary selection and prices this week and I want to pass it on to those interested.

[Cataclysm]

For every 12" of board width you have, it can expand up to a possible 1/8" with humidity, so just keep that in mind.

You can also do a lamination of solid hardwoods onto something such as an MDF substrate for added stability, while still maintaining a solid wood exterior (I did the baffles on my Zaph SR-71's this way).

You just need to be conscious of the fact that you'll be working with real wood, and constantly allow for potential expansion when making panels and doing joinery.


And not to stir the pot, but has anyone ever bothered to measure the responses of two identical, properly braced enclosures with one being made from MDF and the other a solid wood?

[ThomasW]

Given the comparatively short life span of a pair of loudspeakers, it seems like using limited resource like hardwood for furniture would be a better option.

Personally I don't know anyone having 50yr old speakers, but I know people with hand crafted furniture much older than that...

If the goal is something pretty to look at veneer over MDF or BB ply is a good option...

[JJones]

I also agree with what others said about expansion of hardwood potentially being a problem. I had recently been considering a hardwood baffle, but, I'm having 2nd thoughts and will probably just either paint or veneer. I have some 30 year old black walnut boards from when I was a kid and the big walnut tree in our back yard was split by lightning. It would make some beautiful baffles ~ but... Like Thomas said, furniture would be a much better use for it. What if I didn't LIKE the speakers, that would be a real shame, and, of course, they won't last as long as a piece of furniture could.

EDIT: Oh, and Baltic Birch plywood is a joy to work with. I have to find a supply near where I live, they don't sell it at the big home improvement stores. The good stuff with many thin layers and void free is ~ well, I'm at a loss for words how wonderful the stuff is for building speaker enclosures, compared to all the other materials I've tried such as MDF or "regular" plywood.

Edit by moderator to remove off-topic/tangential posting. This thread is about the pros and cons of using of hardwood. It's not a discussion about constrain layer damping.

[Steve Manning]

Bob,

This is what I did on the speakers I finished a little while back. I was like you and ran across some very nice looking hardwoods at the lumber yard. In particular I saw some padauk which contrasted very nicely with the Baltic Birch I was using for the cabinet bodies. Being concerned about splitting I backed the padauk with MDF for stability. The baffle sits in a pocket and the MDF is what’s glued the rest of the cabinet. So far, I have not had any problems with the padauk, we’ll see over the long run.

Steve

[bobhowell]

As long as you keep that speaker in the same relative humidity, you will have no problem. Move it into a high humidity environment and the front will swell and the Paduk will bow out, a little, or alot depending on change. If this happens, just dry it out and it will return to shape. A 10" wide board will increase 1/8 -1/4 " in width when moved from an air conditioned room to a carport, here in the south. Move it to the Arizona desert and small hairline cracks will develop.

To use solid wood you must use it on four of the six faces, with end grain glued to end grain, all the way around. It then will swell and shrink over time in unison with out splitting.

99.9% of the movement is ACROSS grain, with the .01% along the grain, so you can glue MDF, or Plywood to the side grain when you attach the back and front, with no fear of future splits.

An inset floating panel sealed only with silicon caulk will also work as mentioned above.

These principals were old in time of the Egyptians. My solid cherry kitchen cabinet fronts use it in the door panels. You will probably see it all around your house, except for where plywood or MDF is used.

[Cataclysm]

I did something very similar to the gentleman's baffles two posts above:

Images not available

The most obvious advantage to solid wood is that you can machine it in almost any way imaginable and never have to worry about whether you can wrap it properly in veneer, match the grain, make it look right, etc.

[JonW]

Yeah, it would be nice to use real hard wood for speakers. I totally understand the temptation. I wonder if a small cabinet like a desktop speaker might be OK to use hard wood. With smaller dimensions the expansion and contraction issues will be less severe. Maybe I’ll give a shot to the floating baffle idea some day.

EDIT: Oh, and Baltic Birch plywood is a joy to work with.

I totally agree. I hate MDF. That dust is so bad, it’s so fine and gets everywhere. Not to mention how it’s not exactly healthy for you (small particles to breath and formaldehyde). It’s tougher on tools. Screws strip it easily. And if it gets wet your project is done. Compared to MDF, Baltic birch really is a pleasure. Even though the BB is more expensive, I’m still amazed at how many people put up with MDF.

My local wood store used to carry 5x5 sheets of good BB for $39. Not the highest grade possible but better than the occasional stuff you see at Home Depot. Perfect for speakers. They stopped carrying it and can’t special order it. So now I drive an hour away and pay $60 a sheet. Eeek. It’s still well worth it, at least to me.

[Dryseals]

I've used hardwoods for furniture and speakers, no splitting problems. The spitting problems come from using to wide of a piece and no support and building it where the humidty is different than where it will reside. I have a whole house full of antiques, which have seen vast changes in humidty with no splits, so if it's well built, then it will not split.

But if you are not well aquainted with the old ways of working wood, you might want to read a book or two about it. Real solid wood furniture is not easy to build without a split unless you have a good idea on how to do it.

[benchtester]

Cataclysm: Nice Baffle

Thats a nice looking baffle; what kind of wood is it? How did you finish it? :T

[Cataclysm]

It's black walnut, but the cameras color balance made it appear as though it has a reddish hue with the outdoors shot. In fact, the boards those baffles were made from had some *really* nasty knots where the woofer and tweeter cut outs landed... dumb luck I suppose, but I would rather pretend that I planned it that way. :rofl:


Finishing it was very easy:
-finish sand the wood with 320 grit
-1 wipe of tung oil to enhance the grain
-sand with 0000 steel wool
-7 coats of wipe-on gloss polyurethane for durability, again sanding between coats with the steel wool to remove any burs or rough patches.

[cacophonix]

I'm using hardwood as inlays in my subwoofer build.

Had a question for the gurus here ...

The flush trim is kinda old and when i used it to trim the overhang, it stripped a bit more wood than needed. My question is how to best fill in these gaps? I'm looking for something that will cure hard...