Rosewood Soundboard

[Mr. Preston Swift]

i was recently rereading on of my books on wood selection.

It mentioned that Indian rosewood was a denser kind of wood, more so then Mahogany.

I know Guild uses mahogany for it's soundboards and so do others, and of course they sound great.

Since Rosewood is denser than mahogany and already has good tonal qualities wouldn't it too make a great soundboard?

I couldn't really dig up any helpful info on it.

What do you guys think?

[fryovanni]

i was recently rereading on of my books on wood selection.

It mentioned that Indian rosewood was a denser kind of wood, more so then Mahogany.

I know Guild uses mahogany for it's soundboards and so do others, and of course they sound great.

Since Rosewood is denser than mahogany and already has good tonal qualities wouldn't it too make a great soundboard?

I couldn't really dig up any helpful info on it.

What do you guys think?

A better question to ask is what do you want in terms of properties in a soundboard wood. Since you are reading up on wood selection.

The driving force behind acoustic building is efficiency.

Probably the most used soundboard wood is Sitka Spruce. Sitka happens to have one of the best weight to strength ratios out there. This holds true of commonly used soundboard woods. How does EIR rate in this respect. If it is heavier(and it is) how much thinner would it need to be to be in the same weight range as say sitka? At that thickness how would it's strength compair to Sitka(it will be lower)? Since you have to have a minimum strength how much extra material(weight) do you have to add to get the strength up? Then how much efficiency will be lost because of that extra weight you have to move? If that loss is acceptable then you could start looking at how the woods oils, resins, structure may impact the vibration.

Same questions have to be ask of Mahogany, and in the end the sound is different. Not as efficient, but with the right body size it seems to be acceptable. Personally I have never been a fan of Mahogany topped guitars, but some people really like them.

Peace,Rich

[erikbojerik]

You can almost think of an acoustic guitar top like a speaker cone (and the bridge as being like the driver). You want the top to be strong but still light enough and elastic enough to be responsive to the bridge. If you thin rosewood enought to make it that responsive, it won't be strong enough to withstand the string tension (is my guess).

Now, if you use it as one of the veneers on a Nomex-core laminated hollow top...there's an idea worth pursuing.

Nomex

[thegarehanman]

This maybe too thick, but if you're looking for nomex(which is just another name for aramid in honeycomb form), you can get a 2'x4' sheet at .125" thickness for $35 at avtcomposites. The difference is about $4.50/sq ft at AVT vs. $8.50/sq ft at lmii. I've dealt with a few types of honey comb, not nomex, but you could likely sand it to thickness after adhering it to the substrate(soundboard). I've seen nomex soundboards before and a lot of builders cut out an area a few inches smaller in each direction than the soundboard, then taper it to nothing at the edges.

[Mattia]

Mahogany and Koa make quieter guitars than spruces, and they're only just on the edge of being usable soundboards. Rosewood is simply too heavy.

Nomex can get around this to some degree, but rosewood veneer is still heavier than thin spruce by a good bit.

[Mr. Preston Swift]

Is the double top basically two thin soundboards with that honeycomb stuff in the middle. Cause if it is i think that would be a little expensive if i used rosewood

[fryovanni]

Is the double top basically two thin soundboards with that honeycomb stuff in the middle. Cause if it is i think that would be a little expensive if i used rosewood

Your assumtion is correct. Double tops are more expensive.

So I just wanna know if you have found your answer to this question.

"Since Rosewood is denser than mahogany and already has good tonal qualities wouldn't it too make a great soundboard?"

If so what conclusions did you come to?

Peace,Rich

[Mr. Preston Swift]

Is the double top basically two thin soundboards with that honeycomb stuff in the middle. Cause if it is i think that would be a little expensive if i used rosewood

Your assumtion is correct. Double tops are more expensive.

So I just wanna know if you have found your answer to this question.

"Since Rosewood is denser than mahogany and already has good tonal qualities wouldn't it too make a great soundboard?"

If so what conclusions did you come to?

Peace,Rich

I came to the assumption that rosewood would probably make a good sound board, if and only if, the body/bracing is good enough to support it enough to produce a descent tone, Guild i know makes all mahogany guitars so i guess that most back and sides woods could be ok tops too only if they are built with options and stucture to support it enough.

thank you guys and i plan to try this in the future (about a year i guess)

andrew

[fryovanni]

Is the double top basically two thin soundboards with that honeycomb stuff in the middle. Cause if it is i think that would be a little expensive if i used rosewood

Your assumtion is correct. Double tops are more expensive.

So I just wanna know if you have found your answer to this question.

"Since Rosewood is denser than mahogany and already has good tonal qualities wouldn't it too make a great soundboard?"

If so what conclusions did you come to?

Peace,Rich

I came to the assumption that rosewood would probably make a good sound board, if and only if, the body/bracing is good enough to support it enough to produce a descent tone, Guild i know makes all mahogany guitars so i guess that most back and sides woods could be ok tops too only if they are built with options and stucture to support it enough.

thank you guys and i plan to try this in the future (about a year i guess)

andrew

Andrew,

That is what I wanted to know. The conclusions that should be coming across from the responces, and suggested research would be something like this.

1- Rosewood has a very poor strength to weight ratio in comparison to most all woods used for soundboards. This includes Mahogany and Koa which would rate poorly in terms of efficiency(the fact that they are used, shows it can be done however the use produces lower volume and is difficult to make work at that). Efficiency is very important in a sound board if you want it to sound good.

2- Although rosewoods and other very hard dense woods are used for backs and sides. Backs and sides are NOT the primary drivers of sound. They serve the sound box to respond to the air coupling and provide a stiff rim to stabalize the soundboard. It is by design that the back does not work the same way the soundboard does. Because if they responded very close to each other you would have resonant issues that would cancel much of your sound.

3- As a possible method of attempting to make rosewood work well(given that traditional methods of bracing and rosewoods propertise would not allow for reasonable dimenions). Double tops were offered as a possible alternative. Double tops are tricky to design effectively to begin with, and I believe using an inferior wood(in terms of efficiency) such as rosewood. Would make it even more difficult.

4- The issue is not really so much with making the bracing strong enough. It is more that the top itself would have to be extreamly thin to cut weight and develop a top willing to vibrate well. The bracing to stabalize a thin, weak, and heavy top would be challenging and most likely not have good potential to create a good sounding guitar.

Acoustic soundboards are just not like solid bodies when it comes to choice of wood. You need that efficiency as they are quiet instruments to begin with and controlling the sound is so it sounds good is a fine balancing game. Well unless you want to rely on amplification at which point people do build with less effective tops(many times just for the look).

I thought it would be a diservice to you if I just dropped this topic. So for what it is worth, That is my understanding of the potential for Rosewood as a soundboard.

Peace,Rich

[erikbojerik]

Rich knows what he's talking about.

An acoustic guitar back is intended to be nothing more than a reflector for the sound generated by the soundboard. The rim is simply the support structure that joins the two together. Just because you see something used for backs & sides doesn't mean it will serve as a good top, they have entirely different functions.

[Mr. Preston Swift]

that is exactly what i needed to hear

thanks everyone (rich)

now i'm convinced that it will not work too well

thx