Hardwood Baffles?

[snmhanson]

I am close to getting started on my Statement Monitors/sealed CC and am thinking about going to get some materials for the cabinets. I plan on building everything out of MDF and then veneering it except for the front baffles. I was going to use some sort of a hardwood but I have seen a few comments about hardwood not being appropriate for speakers due to expansion and contraction. Is this a big issue for a removeable front baffle of about 10 1/2" wide?

My plans include an initial 1/2" MDF sub baffle which will be part of the speaker and then the 3/4" hardwood baffle being essentially bolted in place and removeable. I have also just thought about making the front baffles a single 1-1/4" thick but it would make my particular build a bit more difficult so I'm not sure that I want to do that. I have seen a few designs that have what appear to be hardood baffles but I can't say for sure that they are hardwood and if they are, how well they worked long-term. I just like the idea of a replaceable and contrasting front baffle and it would be fun to try different species of woods to be able to change the aesthetics of the speakers from time to time.

Thanks for any input and enlightenment.

Matt

[Delta Dog]

I am using an oversized 3/4" piece of mahogany for my baffle with a 1/2" MDF glued to it to fit inside the sides for my Statements Monitors. I plan to veneer first then use a flush trim bit on the solid piece. Finally I will use the roundover on the solid baffle. The last thing I will do is glue on the baffle.

[JonMarsh]

Laminated Bamboo Lumber- pretty stable, rated about 15-18% harder than maple, fairly easy to work, but not cheap or easy to find.

Have used it for complete front panels as well as a composite layer with other materials.



Looks pretty nice with a clear lacquer finish. Looks best with piano black for contrast, IMO, so I'm going to rebuild these.

For best dimensional stability, for any hardwood, finish all over, front and back, to prevent moisture absorption.

[snmhanson]

Thanks for the replies. Delta Dog, I'd be curious to see your design when your finished. Your process is similar to what I am thinking. The only difference is I am going to have curved sides by using multiple sheets of 1/4" or 1/8" plywood so I am not sure how easy it would be for me to end up with a nice flush edge for the baffle to fasten to, hence my decision to permanantly attach the 1/2" MDF. Santos Mahogony is one of the species I am considering for the baffle but I am also looking at Sapelle, Bubinga, Amboyna and Tornillo as well as a few others. I like the burled finish on some species but then I also like the fine and subtle grain of other species. My tastes tend to change over time, hence my decision to go with a removeable/replaceable baffle. Maybe instead of starting new speaker projects when I get the itch I can just build new baffles.

John, I like the bamboo baffles. We have bamboo floors at our house and with three young children I can attest to their stability and durability. Looks like you used vertically laminated bamboo. I wonder if horizontally laminated would be as stable. I live not too far away from Portland, Oregon where there are quite a few sources for bamboo so maybe I will look into that as well. Maybe I'll even look into doing bamboo veneers for the rest of the speakers, although I would lose the contrast I am after. Thanks for the tip on finishing the hardwood.

Matt

[5th element]

Here's a loudspeaker that I built using a similar method to what you described. I glued everything together though, no bolts.

The speaker is finished in mahogany.

I've not had any problems with wood expanding and contracting, but then I live in the UK and our climate doesn't vary that much.

[snmhanson]

Looks nice 5th element. Are all of the surfaces mahogany or just the baffle? While I live in the Pacific Northwest and we have definate changes in climate, the speaker is still going to be in a conditioned room so maybe expansion and contraction won't be too big of an issue. Plus if I can create a good seal between the sub baffle and the hardwood baffle it shouldn't really matter too much if there is a little shifting, other than possibly aesthetically.

Matt

[5th element]

Just the front is solid wood, everywhere is veneered.

I think people worry too much about wood cracking, MDF expands and contracts too! Of course it cannot crack, but it does create visible lines underneath veneer sometimes. You would probably have trouble if the wood hadn't dried out. But no one would think of building something like a loudspeaker out of it in the first place.

And of course, if beneath, the wood is glued to the cabinet, and the front side is finished with a non porous coating, then it should be quite hard for moisture to get in.

[liasom]

...I was going to use some sort of a hardwood but I have seen a few comments about hardwood not being appropriate for speakers due to expansion and contraction. Is this a big issue for a removeable front baffle of about 10 1/2" wide?...

...then the 3/4" hardwood baffle being essentially bolted in place...

I'm doing a project using 1/2-inch solid Douglas Fir for the baffles, but ZBM4s are small compared to what you would need to do for your project. My baffles will be glued up to 3/4-inch plywood so I'm hoping to alleviate any issues with dimensional stability that way. Before I started planning I researched a lot and I think (maybe) success mainly depends on where you live, the species of wood you choose, and the moisture content when you work it to make the baffles. There are a lot of sources to find the answer to those last two questions. If you can't answer the first, well, 8O.

If you're artistically/creatively unchallenged you might consider faux painting, specifically graining, as a way to achieve changing "the aesthetics of the speakers from time to time." I'm sure it wouldn't be easy-as-pie but also don't think it would be too hard to learn the basic skills and do some practice. Paint over MDF is cheap when compared to most hardwoods. I've seen some cabinet work finished this way and it is amazing what can be done. You could make up a couple of sets of baffles during construction.

[liasom]

Wanted to add a link to these photos during my previous post, but couldn't remember the website. The casework of the organ at The Episcopal Church of the Transfiguration in Dallas, TX is faux grained--the reddish colored wood. If I understood it correctly from the organ builder, Bruce Fowkes, the basic process they utilized overall involved a light colored undercoat, then painting in the dark graining, and a red translucent glaze over the top. There are two hi-res photos you may access at the bottom left of their Opus 17 webpage under "Media", Richards, Fowkes & Co. Opus 17. They also used faux graining on their Opus 15 in Knoxville (UT Knoxville), a brown colored wood finish. I've seen the Dallas organ both up close and from afar. It's stunning.

[bobhowell]

A solid wood baffle will work on a MDF/Plywood box, if it is installed to allow sufficient wood movement. All the movement will occur across the grain, so, in the width only. Don't pin it but let it float on a foam rubber seal and you have solved the problem. Use 4 or 6 Bolts, in over-sized holes, as Zaph describes for his baffles and the 1/8-1/4" movement will not cause problems. It will slowly move that much from season to season and a good coat of finish will dampen the change, but not stop it. If you move them outside for a month, a good finish will prevent much swelling, whereas bare wood would move 1/16-1/8". Over 6 months they would move about the same whether finished or not.

[ahaik]

I had the same debate regarding my Statement Monitors, its been over a year since I finished them, so far no visible cracks and I like the look of real wood much better then veneer.
The baffles are 3/4" curly maple backed by 1/4" MDF.

[LoveDoctor]

Woodworking Noob question:

I'd like to try a bamboo hardwood baffle similar to JonMarsh's post above for a set of upcoming Aviatrix LCRs, but I've really only worked with MDF. I have all the standard woodworking tools most of us use for simple MDF boxes (table and circular saws with carbide blades, router with flush trim and roundover bits). Aside from working slow and doing multiple passes with the router (rather than trying to get all the material in one pass), anything else I should be aware of? Will standard new-ish router bits be OK if I'm patient? I assume bamboo will wear down bits and blades a bit faster.

Matt/snmhanson, I'm also a Portlandian. I know there is a hardwood supplier somewhere in the NW Industrial area (the name escapes me), but any other sources you prefer? Thanks for any leads.

[Space]

I'm also a Portlandian. I know there is a hardwood supplier somewhere in the NW Industrial area (the name escapes me), but any other sources you prefer? Thanks for any leads.

I can field this question--you're probably thinking of Crosscut in the NW, and they do sell bamboo plywood. But you have to buy 4x8 and it's at least $200 / sheet. There are some other vendors--Ecohaus and Bamboo Revolution in the inner SE. But again they sell full sheets.

Some have chosen to use cutting boards from Target for their baffles. There's also an outfit in Portland that sells artist panels made from bamboo or Appleply: Plywerk. That may be a good option if you don't want a full sheet.

[snmhanson]

Woodworking Noob question:

I'd like to try a bamboo hardwood baffle similar to JonMarsh's post above for a set of upcoming Aviatrix LCRs, but I've really only worked with MDF. I have all the standard woodworking tools most of us use for simple MDF boxes (table and circular saws with carbide blades, router with flush trim and roundover bits). Aside from working slow and doing multiple passes with the router (rather than trying to get all the material in one pass), anything else I should be aware of? Will standard new-ish router bits be OK if I'm patient? I assume bamboo will wear down bits and blades a bit faster.

Matt/snmhanson, I'm also a Portlandian. I know there is a hardwood supplier somewhere in the NW Industrial area (the name escapes me), but any other sources you prefer? Thanks for any leads.

Yeah, Crosscut Hardwoods is where I generally shop for my hardwood needs. I could (and have) spent hours looking through their inventory. There are other vendors in PDX but I typically just go to Crosscut for my hardwoods. As far as bamboo, the only place I have really dealt with is Endurawood Products and that was several years ago. I think they are more of a fabrication shop but they do (or at least did) sell materials as well. Being a fabricator, they may have some odd sized pieces or something left over from a project that they might be willing to sell. May be worth a call to them. Otherwise, there are quite a few bamboo vendors in the area. If you can't find anything smaller than a full sheet shoot me a PM - I may be up to splitting a sheet with you. I was hoping to find something 1-1/4" thick but I could probably make 3/4" work for me. Sound's method of using a bamboo cutting board is also a great idea as long as you can find one big enough and at the right price.

One final thought, I was talking to the contractor who built our house and he just installed strand woven bamboo flooring in house he is building. He said it seemed very stable and durable - even a step up from conventional bamboo. It looks pretty cool and is a little more verigated than regular bamboo. Here's a link to a manufacturer although I'm not sure where to get it locally: http://www.teragren.com/products_panels.html

Matt

[LoveDoctor]

Space/Matt, thanks much for the info. I called and Bamboo Revolution does have smaller cutoffs from 4x8' sheets, so I'll be stopping by there tomorrow. Who knew there were so many Stumptowners on here?

Matt, thanks for the info and sorry for the threadjacking...

[snmhanson]

No worries about the threadjacking. It's always nice when a thread you start also helps someone else out. I noticed quite a few PDXers on here as well - although I am actually in the Columbia Gorge about and hour out of Portland. Maybe we could organize a Portland area DIYer event sometime. Of course I would need to finish up (actually get started on) my speakers first. So far I have only built a subwoofer but there is definately more to come.

Matt