The Steel Guitar Forum

Johan, I remember reading, that Shot Jackson din't want people to know ebony was available choice of wood on early Sho Buds, because it was very hard to work with and very expensive. However my -63 Sho Bud has an ebony front apron ( with maple top ).

Here are some more rankings of woods by speed of sound transmission, measured directly. The two sources for these used different units of measurement, in one case not disclosed, so I can't combine them. Note that whatever mahogany is listed on the upper list is significantly above the maple listed. The lower list doesn't indicate (sub)species. Clearly, (sub)species vary widely, and even wood from the same tree can vary widely -- there is no gospel here. Note also that none of this information includes what Dana Bourgeois et al. refer to as "damping." In addition to having superior sound transmission ability, graphite composite, bakelite, formica and aluminum are much more controllable for consistency, which certainly has its advantages; but then, the complex variability of individual instruments made from the "same" materials by the same builder is part of the wonderful charm and mystique of PSGs, or any musical instrument.

fir (various) 3709-4070
Port Orford cedar 3643
Sitka spruce 3625
eastern white pine 3621
basswood 3598
Engelmann spruce 3418
poplar 3406
redwood 3228
eastern white pine 3228
cherrybark oak 3146
mahogany 3100
sweet birch 3044
black walnut 2920
bitternut hickory 2523
bigleaf maple 2500
teak 2472
blue ash 2377 (not what Leo used...)
white oak 2332

iron 16,822
ash 16,677 (maybe what Leo used...)
aspen 16,677
acacia 15,467
sycamore 15,314
elder 15,306
fir 15, 218
elm 14,639
maple 14,472
poplar 14,052
oak 12,662
beech 10,965
pine 10,900
<FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by Jack Anderson on 30 October 2002 at 05:12 AM.]</p></FONT>

We used a mahogany top and maple sides on my keyless Zum. It sounds different than my all maple Zum, but of course is keyless and also has a "comb type" changer support. I wouldn't say it is better or worse, and is changing all the time as it decides it wants to be a guitar rather than a board, but it does have remarkable sustain. Time will tell if it was really a good idea or not. My 2000 model Zum is just now starting to sound REALLY good as it develops more of that low mid growl. It's almost three years old now.

------------------

Doug Earnest
The only Zum Keyless U12, Fender Cyber Twin

Jack,

Regarding the ratio for aluminum, My Mechanics of Materials book shows the following:

Aluminum

E = 10 x 10^6 psi

Density = .098 lbs per square inch

Ratio (drop the 10^6 since we are comparing) = 102.05


Spruce

E = 1.3 x 10^6 psi

Density = .016 lbs per square inch

Ratio (drop the 10^6 since we are comparing) = 81.25


Douglas Fir

E = 1.8 x 10^6 psi

Density = .019 lbs per square inch

Ratio (drop the 10^6 since we are comparing) = 94.17


I guess your ratio comparisons include another constant or is for SI units, but for comparison only the difference matters.


Check out these numbers:

Steel (A36)

E = 30 x 10^6 psi

Density = .284 lbs per square inch

Ratio (drop the 10^6 since we are comparing) = 105.63. - Hmmm, should our steel guitars be made of steel?


How about titanium?

E = 16.5 x 10^6 psi

Density = .161 lbs per square inch

Ratio (drop the 10^6 since we are comparing) = 102.48 - Similar to aluminum and steel


What kind of reference text did you find the speed of sound transmission info in?

Scott, I could use a good reference text, but have just been doing "Google" searches and collecting excerpts from websites for some time, and haven't been good about keeping track of the sources. The numbers like "Port Orford cedar 3643" are just "comparative numbers" without any detail as to how they are derived, but they may be the speed of sound in meters per second. The numbers like "white ash 2.03" are the ratio of Young's Modulus (as N/m2) to specific gravity, while the numbers like "acacia 15,647" are the speed of sound along fibers in feet per second at 20 degrees centigrade. This doesn't make for very good comparisons, especially when the (sub) species is not identified. They are still food for thought, however. I did see a source for the speed of sound in aluminum (5,000 m/sec), iron (5,103 m/sec) and steel (5,200 m/sec)and have long wondered about making a "steel" out of STEEL. I probably wouldn't play out on it very often.... I am very interested in titanium, especially for changer fingers and nuts/rollers, where the low mass should transmit better between string and wood, for coloration etc., as aluminum purportedly does, and where the hardness would be helpful vs. wear from strings. MSA and the luthier community have really fired my interest in graphite composite, too, I must say -- not necessarily for the whole guitar, but at least as a great way to tie together and strengthen nice sounding pieces of wood.