Which way would you orient this sinker redwood top?

Here is a question for the more experienced builder. Here is a set of book-matched sinker redwood top. Which way would you orient this set of tonewood and why?

With evenly ~ 15 rings per inch across.



The dark region center has ~ 33 rings per inch and then decreases to 15 rings per inch

Overlay a circle where the sound hole would be to help you decide. It also of it depends on the side and back wood.

Personally I like the second

I like the first as being more visually appealing.

I could care less how many rings per inch any wood has. It comes down to how it feels between your fingers, and it's looks. You can always adjust stiffness both across and with the grain with your bracing.

But, acoustically, I am not sure... I found myself arguing between the two. By the way, the back and sides are gong to be cocobolo rosewood.



Yes, Allen, I think that is where I was going... different bracing?

I like first one.

Without the boards in hand it's impossible to give specifics.

For instance, what size of instrument?

Is it going to have a dome or radius built into the top? What sort of thickness is the top going to be? Are you going to thin the perimeter of the lower bout? What are you hoping to achieve with the instrument?

Will you use fan braces? How many? What about a bridge patch? Is it going to span most of the lower bout, or just under the bridge? How thick will your bridge patch be? Are you going to taper the wings on it if you are using them? And what about the bridge? Is it going to be a small footprint, or will it have wings?

Every single one of these things on their own will affect the stiffness of the top in either the cross grain or along the grain stiffness. And thus the response you will get from the instrument. Combine them all to varying degrees, and there are infinite possibilities.

All the sorts of things it takes dozens of instruments under your belt to build up any soft of an idea of what you want to accomplish.

One thing is for sure though. It will sound like a ukulele.

Conventional wisdom in the guitar world would say to have the tighter grain in the center. I'd guess to keep the stiffest wood under the bridge and to let the vibrations flow from stiff to less stiff areas. Maybe there's something to that or maybe its just what everyone does. I like the color variation on the second photo so I'd go with that

Allen said:

Without the boards in hand it's impossible to give specifics.

For instance, what size of instrument?

Is it going to have a dome or radius built into the top? What sort of thickness is the top going to be? Are you going to thin the perimeter of the lower bout? What are you hoping to achieve with the instrument?

.....

All the sorts of things it takes dozens of instruments under your belt to build up any soft of an idea of what you want to accomplish.

One thing is for sure though. It will sound like a ukulele.

Click to expand...

Yes, it will sound like a ukulele, I hope... a tenor.

Of course, in no way I was trying to make light of the skills, experiences and knowledge of the builder. The work of a luthier is all above plus art, science, and to some extent... instinctive feel for the wood that is siting on his/her bench. Facing these two choices (tight grain in the center or ever grain across) what will be the first thing that ran through your mind in getting the most out off it... or maybe not?

Really appreciate all your replies.

Conventional wisdom says the narrower grains (out side of the tree) go to the middle. I like the way the first pic looks better, and I say it matters little in RW on a tiny top where run out is unlikely to be an issue, assuming it was properly milled.

I'd do the second but i'd cut out the dark line in its center and use that wood (tight grained & stiff presumably) for top braces if appropriate.

I was thinking of cutting off the top strip of the Cocobolo rosewood as the center reinforcement of the book join (i.e. crossed grains)... making use of the properties of the same wood. Never thought about using some of the top wood as possible top bracing materials....

This is a very "system" approach and a very interesting insight of your luthier thinking... thanks Beau!!

ive used redwood for top braces and the tops tap the same as those with spruce braces. I did a few quick bend/deflection tests by projecting the redwood braces and spruce braces of similar dimensions (about 5-6mm square) over the bench edge about 4" and just finger tested them- they were very similar- well, some were stiffer, some floppier for both spruce and redwood- i just chose the best ones
Your fingers will be able to tell very easy the subtle differences in stiffness.