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What would you say are the general tonal influence of engelmann compared to Sitka?

For instance, I would say lutz has less headroom but more overtones that Sitka.

I know that each piece has its own traits, but I do feel that there are certain generalizations that are useful. Otherwise, how would we choose a top wood?

Thanks

I think Dana Bourgeois description is well said. Most of my guitars are Sitka or Engleman and several Cedar too but I have always thought that the Sitka tops are brash and metallic and very loud and the Engleman tops are softer and more complex. And that's talking about the exact same model guitar too.

Velocity of sound: how is this being measured and what would be the difference in timbre between fast and slow?

I'm skeptical of this term.

James Goodall's take on this question. From his website..
OK, here is what I think about the different top woods:

•Sitka Spruce
This is the strong one. For its weight, it's one of the strongest woods in the world. Color range from light yellow to medium orange. Usually exhibits fairly strong silking (medullary rays). Best if medium gauge strings are used but good for light gauge also. It has possibly the best balance between the bass, midrange and treble. It has a strong fundamental but also a midrange brightness. Loud, but not the loudest for fingerstyle. Doesn't break up when flatpicked hard. The denser pieces can be thinned a little more than the other top woods, perhaps .005" to .007" more.


•Engelmann Spruce
Slightly less strength than sitka and generally softer, but some pieces can be quite stiff and strong. Creamy white color, less pronounced winter growth lines, and generally good silking. Beautiful, rich, sensitive tone frequently recommended for fingerstyle and light flatpicking. Good bass, slightly less midrange brightness than Sitka, with a brilliant overtone harmonic structure. I feel opposed to using medium gauge strings, at least with the softer pieces as I think over time it can be detrimental to tone.


•Red Spruce
Red spruce, also known as Adirondack or Appalachian spruce, was used by wood-frame airplane builders early in the century because of its high strength-to-weight ratio. Some of the tops exhibit very high stiffness both with and across the grain. Red Spruce is better known for its tonal qualities than its appearance. Master grade tops look similar to Engelmann spruce being a creamy white color but exhibit very little silking (medullary rays) and rarely approach the beauty or the fine or even grain of Sitka or Engelmann spruce. Some tops have slight discoloration but because few red spruce trees are of guitar top size or quality this is perfectly acceptable. We find the tone of red spruce loud and powerful with a focused, punchy bass. Many flatpick guitarists find this to be a choice topwood.


•Cedar
Slightly less strength than Engelmann. Color ranging from light cocoa brown to reddish brown to medium dark chocolate. Doesn't exhibit medullary silking. Scars fairly easily and braces can shear off if bumped. My personal opinion is it's better suited to classical building than steel string but our cedar/rosewood Grand Concerts and Standards sound quite impressive right from the start. Light gauge strings only. Powerful fingerstyle tone with lots of brilliance and sustain, exceptional clarity, and focused bass (with a dry, woody sound). Less sensitive to humidity variations, and dampens the string noise less than the spruces. Some small question about long term tone quality.


•Redwood
Description almost identical to cedar but a little more red in color. It usually exhibits a beautiful glow, with strong medullary silking - some pieces amazingly so. Glue bond not quite as good as the spruces. Again, light gauge strings only. A quality redwood top makes a fingerstyle guitar which is hard to beat with respect to a responsive, 3-dimensional brilliance. Some tops exhibit somewhat more richness in the bass than cedar.


•Koa
Acacia koa is a native hardwood exclusive to the Hawaiian Islands. Koa has an amazing variety of figure and color ranging from a light golden yellow to dark brown. It can be highly figured and exhibit a beautiful, luminous inner glow. We offer koa in five grades, all of which are gorgeous. The koa we select for our tops is picked as much for its tonal qualities as its figure. Some of the less figured wood may actually be better tonally. The tone of a koa top is of good quality, being musical and sweet with a different sustain quality than spruce top instruments. The notes don't rise and jump out as quickly and powerfully as Sitka spruce but sustain more evenly. In my opinion our instruments with all koa (back, sides and top) would be an excellent choice for jazz style playing with amplification.

There is quite a variation with the timbre of these woods. There is also a crossover in tone between the spruces and between cedar and redwood. I favor the spruces but am always pleased and impressed with the tone of our redwood and cedar top instruments. What I have described in each category is the average. I like the pieces with the highest stiffness to lightest weight ratio, especially on the larger guitar models, although my Jumbo can use a little heavier top. The Parlor and Grand Concert series instruments can sometimes benefit from a more flexible/light top.

Thanks...

My experience with Engleman is exactly what the others have said. Softer fundamental, complex overtone series. In a sense, you could think of it as the cedar of spruces.

People always say that WRC doesn't have silking but I've used several pieces that show it.

WRC can have heaps of silking.

As part of his PhD, Ra Inta with Gerard Gilet built three "identical" guitars differing only in their top woods, WRC, Engelmann and Sitka and, if you thickness the tops all the same, which these were, you get performances that broadly align with the street speak. If you thickness according to material properties, the performance is much more similar with the residual differences being mainly due to the sound spectral absorption (damping, [Q or log dec.] being a poor approximation of this) of the different species, with WRC being the species having the lowest damping (in general) and Sitka the highest of the three. So when someone says Sitka is "more fundamental" it just means that the higher harmonics attenuate faster because of the higher damping.

So it's mostly down to design; but if you want a guitar with lots of high harmonics, build with cedar. The guitar pictured is about the only "stock" model I do, but it's just outstanding as a fingerpicker with singing high harmonics right up the fret board where spruces begin to fade.

Details, as ever, in the usual place.

_________________
Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

So you're saying that if you thickness according to vibrational properties or deflection testing, you will notice less difference between the different top woods?

Trevor, what is the wood used for the bridge and bindings????????

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MK5acoustics.com

If you thickness according to vibrational properties (stiffness and density), correct; because the modal frequencies largely determine the sound of the guitar, so make those the same and the guitars will sound largely the same. If you thickness according to deflection testing, no, because you've only taken into account the stiffness of the wood, not its density. If you just thickness to a target, it's a crap shoot, because you've taken no notice of the material properties at all.

That's figured Aus. blackwood; same in the rosette. The bridge has a FP finish on it, or it wouldn't stay looking like that for very long (for those following the "is it OK to put a finish on a bridge" thread).

_________________
Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

Maybe I missed it in the usual place, but is there a way, beyond trial and error, to determine what the 'right' freq before bracing for a given model should be? Several post examples are included, but not pre, unless I missed....

Section 4.5 in the Design book. Maybe start at the end, Section 4.5.6, the section summary, then go back and study the detail.

_________________
Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

Thanks...

Any questions, BTW, probably best to address via the section on the ANZLF.

If you are looking for a "right frequency" to thin to before bracing, unfortunately, although a valid way theoretically of doing things, practically it's really hard to work like that, because when you're down toward the right thickness it is very hard to get a clear tone to either measure or to listen to. The resonance is "quenched" as someone once wrote, and when it is and when it isn't is a range, not a point. Hence the method of measuring when thicker, when the tap tone is more audible, defined and measurable and then figuring out the right thickness to end at from there.

_________________
Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au