The great woods experiment

**trevor** · Mar-17-2008, 9:49am

This has been on my website for a week or two now but I've been to busy to post about it.

I have long been curious about bluegrass mandolins and different woods so I asked Bill Bussmann (Old Wave) to make for me as near as possible identical A4 mandolins with back and sides in walnut, rosewood, maple and mahogany. Then I asked Dan Beimborn and Simon Mayor to give their comments. All is revealed here;
http://www.theacousticmusicco.co.uk/x4042.html

**Red Henry** · Mar-17-2008, 10:22am

Trevor--

That's an outstanding group of mandolins by an excellent maker, and expert writeups too. Thanks for letting us see them.

The success of the walnut mandolin doesn't surprise me. When I began building my first mandolin in early 1981, I had some nice old walnut, so I asked Randy Wood about it. He said that walnut would make a fine mandolin. So I made my A-model back of multicolored burl walnut, and sawed out straight strips for the sides.

(That's all the story there is, because at that point I started building a recording studio and 27 years later, the project's still on the shelf. But if Randy, Simon, and Dan all say that walnut makes a good mandolin, it has to be true!)

Red

**Spruce** · Mar-17-2008, 10:57am

Well, you say that "all from the same section of the same Navajo mountain 10,000 ft. elevation Engelmann spruce harvested in 1998 by the Hurd brothers", but I can see from all these miles away that those tops have different characteristics...

Number Four, for instance, I would bet is much heavier than the other 3. #See that compression graining? #That usually denotes a heavier spruce....

I don't mean to throw cold water on your experiment. #

I love experiments like this, and gabbing about it...

But it would not have been that difficult to grab 4 tops from the same billet to narrow down the variables a bit, as the top is where a good % of your tonal characteristics are coming from...

Can you give us some insight on those tops, Bill? #Maybe the lighting in the pic is just bad.... #

**bradeinhorn** · Mar-17-2008, 10:59am

cool experiment. i'm glad the walnut was so well liked. i agree it makes a great backwood, especially for oval holes.

**trevor** · Mar-17-2008, 11:05am

Bruce,
Bill did mention at the time that one of the tops was heavier despite being from the same tree! I have emailed him about the thread so I expect he will respond.

**bradeinhorn** · Mar-17-2008, 11:17am

interesting observation bruce. can you describe what the heavier top will do sonically? trevor -do you know which mando got that top?

**trevor** · Mar-17-2008, 11:29am

Can't remember, Bill?

**oldwave maker** · Mar-17-2008, 11:44am

The heaviest top was paired with the rosewood, which was the heaviest back. I could have built them all with the same billet had I bought that billet from you, Bruce, and cut it meself, but these were a part of bundle of a dozen tops I bought out of the back of Mussers van when he came thru arrowhead hunting, from the log he had obtained from the hurd bros. I wonder if compression grain is more intense on the downslope side of the tree? any generalizations about weight of tops cut from the north facing side vs. the south side of the trunk? An the under the finish shot maple1 walnut2 rosewood3 mahogany4:

**Frank Russell** · Mar-17-2008, 12:18pm

There's a guy that lives near me in the high desert not far from the 29 Palms Marine base who makes all his mandolins with walnut back and sides. Amazing bluegrass machines, loud as can be, super projection. Only trouble is he's a bit eccentric (and not in the charming Bussman way), and several years ago wanted about $3400 or more for an "A" model or two point. They are good sounding, but I couldn't justify that kind of dough on a virtual unknown. He makes good flat top guitars too. I saw a local group play with almost all their instruments made by him, even a stand up bass. Interesting guy, sure changed my mind about walnut. Frank

**Spruce** · Mar-17-2008, 12:24pm

Thanks for that, Bill...

"I could have built them all with the same billet had I bought that billet from you, Bruce"

Ya know, even then you could have tops with different characteristics...

Sometimes I think that wood just doesn't want to be figured out...

Bring on the composites...

**first string** · Mar-17-2008, 12:42pm

Yeah, I've got to say that I really wonder what effect the heavier top had. I actually liked the tone of the rosewood the best, but it clearly didn't have the volume of the others. As someone who's having a rosewood backed mando made, I hope that there were some other factors influencing that fact...

**Red Henry** · Mar-17-2008, 12:47pm

...and then sometimes the heavy tops seem to take the longest to come around as the instrument ages, but can really sound good when they do. I'd like see a comparison of these mandolins in 5 or 10 years... right now, so I don't have to wait...

Red

**Dave Cohen** · Mar-17-2008, 1:08pm

I've been bonking top plates and back plates in varying stages of carving, partially assembled instruments, assembled instruments in the white, and completed instruments, into an fft program on my computer for a while now. Here's the de-generalization: You can record spectra for two tops that were right next to each other in a billet, and they can either be quite similar or surprisingly different with regard to the peak frequencies of the several lowest free-plate modes. Once you finish your carving and assemble them into an instrument, the differences are less marked. Kind of reinforces what Martin Schleske published several years ago in CASJ. He was trying to get at just what free-plate tuning in violins a'la Hutchins, Saunders, et al, does for the completed instrument. So he "tuned" some carved plates according to the then-current conventions, and didn't tune others. Took modal and spectral data on all of them at stages, then took modal and spectral data on all of the completed instruments. To conclude a short story made long, he found that the modal frequencies for all of the completed instruments were similar, regardless of whether they had been "tuned" or not! Hindsight and referring to the textbook analysis of plates tells us that the free-plate modes and the assembled instrument modes are really completely different things. The geometry and dimensions of the boxes we make strongly influence their mechanical vibration, though characteristics of the individual pieces of wood do remain.

http://www.Cohenmando.com

**oldwave maker** · Mar-19-2008, 11:21am

So yesterday Musser dropped of another dozen vanilla engelmann delights after his paleolithic search, I told him about the ezperiment and he commented that in the guitars he's made (he keeps the best engelmann for his own guitars), the rosewood gives a rounder sound with the most overtones, the walnut drier with less overtones, the maple drier still, the mahogany driest with best fundamental.
Forgot to ask about the side of the tree and slope differences, but left a message this morning.
Interesting that in this group the walnut was my favorite, in the last group the rosewood was.
My next experiment should have even more difference, as I plan a quartet with local black walnut (same 1/4 of tree trunk) sides/back/neck, and tops of colorado and idaho engelmann, adirondack red, and transylvanian euro. I suppose all the bracing should come from the same billet for a semblance of control?