[BoJonJovi]

I would like to get the thoughts of others for wood choice specific to OB; not boxes.

This morning I have been researching resonance of different types of wood. It seems instrument makers are very particular about what wood they use, why and where in the instrument they use it. They typically like woods that do resonate in certain ways to add certain qualities and color to the the sound. For them, the wood is an extension of the resonance of the string or key. I am thinking a speaker maker would not want to recolor that sound they try so hard to create so to speak. I was also looking at the Wharfdale speakers that were sand filled to reduce resonance. This all has me pondering; what about wood?

When I got my Industrial Arts Major I took a class in wood science, basically my emphasis was on wood working. It seems most people put little time in thinking about materials and associated resonance and dampening. I am wondering if a follow the leader isn't taking place and the leaders in wood selection is box makers rather than OB makers; two very different things when it comes to acoustics and structural needs. From the little research I have done this morning I am leaning toward softwoods for my next OB, specifically Aspen.

For a box, aspen or cedar certainly would not be my first choice for a number of reasons. Specifically the wood splits easily, does not hold nails and screws and glue joints are not that strong because the wood is not that strong. But that is of little consequence to a OB maker that really just needs a flat board or slab and not huge amounts of structural strength.

I have a mill very close, where I know I can get aspen. It is a very light wood with big cellular structure.   I have an Aspen sauna that I built that is dead quiet. I have also found it is very cool to the touch in the sauna for the same reasons; big soft insulative pours, which is why I selected it for the Sauna. I didn't want to burn the beggebers out of my kahonies.

I would think dense MDF or expensive Baltic birch might actually be inferior for OB being tighter and more resonate. Both aspen and cedar have fairly low resonance and good dampening characteristics. I can get cedar fence posts 6" x 6' X 3/4 for $2.30 or so a piece at Lowes; they would need milled as they are rough cut.  I did not look for 2/4's but I suspect they have them and that would be better. I have a planer and could plane them and glue them to get a thicker or wider piece depending on whether a guy uses the 3/4 slats or 2/4's. However, that seems like a pain.

Through the mill I could get rough cut aspen cut to 2 inches thick and say 6 inches wide then mill it to dimension.  Aspen is gorgeous when milled and finished, it just will not take much abuse as it is so soft. Aspen wainscoating is also available in my area that could be used to surface a denser wood and add a little pizzaz to an otherwise ordinary piece of pine/hemlock plywood.

Anyway because softer more porous woods have less resonance and more dampening ability it seems they would be a great choice over harder, denser more resonate and less dampening woods.

Consider:
http://www.usc.edu/CSSF/Current/Projects/S1809.pdf

http://www.wrcea.org/technical-specifications/natural_properties.htm

http://tonewooddatasource.weebly.com/technical-data.html

http://link.springer.com/article/10.1007%2Fs00226-007-0170-5#page-1

My gut feeling is we are spending good bucks on expensive wood when there may be cheaper alternatives that will preform better in a wood slab configuration.

I may be way off base and certainly my knowledge base on speaker making is not nearly up to what others on this board is so I must ask; what about wood.

To perhaps further this discussion, I recently "kinda" built some H-Frame woofers.  I did not want to go to the trouble of making a cabinet so I took the easy way out and bought a concrete tube for building piers. I used Martin's length and the volume was about the same so I figured sound qualities might be similar. Although the concrete tube was wax coated and nearly nothing would stick to it, it took a coat of latex very well. At any rate, I am very pleased with the sound. So once again I ponder, perhaps the cardboard which is less dense than wood maybe was not a bad choice when it comes to resonance and dampening properties. It was surely much easier for an amateur to do and at less than 7 bucks a foot for an 18" - 24" diameter tube, the price is right. After I cut it, I reinforced the edge with Elmers and construction adhesive. The results were good enough for me considering my age and time left on this earth.


Anyway, looking for thoughts and pondering of others. Besides, It might be a nice break from talking about speakers and crossovers and everyone loves the smell of wood with their coffee in the morning.

[planet10]

We have built some boxes out of solid Western Red Cedar and gotten really good results. With an OB actual details of thebaffle substructure i think would be very important.

dave

[matevana]

You may want to take a look at my thread in this circle entitled "Mini H-Bombs". It tests compressed cardboard as a baffle material particularly for OB. The point is that sometimes less dense materials have damping properties that may be beneficial in our case (while this might not apply to the high internal stresses of sealed or even vented enclosures). If you find this to be true, it might open your build up to some more exotic woods such as alder, swamp ash (soft ash), koa, pao ferro, etc.

Warmouth Guitar Products in Washington state has some particularly nice rectangular slabs for DIY guitar bodies that could lend themselves to a highly figured OB baffle. Most of these materials have a certain sonic characteristics (signature) that is sought after for solid body electric guitars. Woods are generally separated into categories such as hard (maple, mahogany, oak, etc.) and soft (alder, basswood, etc.).