Re: what makes a good wood?
The proper selection of wood for an instrument is actually one of the more tedious processes. I´ll try to put it a bit into easier terms and not go too in depth, because this is actually quite the anal process when you want to do it right.
1. The wood needs structural stability: particularly on an electric, the wood has to hold up to some pretty heavy loads, on an acoustic the bracing does most of the work here, thereby allowing the use of spruce or cedar without the top buckling in seconds. This requires a certain density of the wood canules (wood is essentially a system of microscopic tubes) as wehh as inherent strength of the fibers themselves, or the stability won´t suffice and you´ll quickly wind up with an accordion when strung up
2. the wood also needs to be dense enough to transmit vibrations effectively.
3. as a general rule you want wood that fulfuills criteria 1 and 2, but is still as light as possible, especially on an acoustic. The lighter the top, the easier it is to overcome the top´s inertia and get the guitar vibrating.
4. You want to avoid knotholes and similar imperfections in the wood grain because these can cause the semi radially expanding sound waves to be skewed off in "improper" directions making for problems with tonal response or causing sympathetic resonance issues.
5. it has to look good if it´s to be transparently finished, or the guitarist will never accept it.
1 and 2 essentially rule out most of the lightest woods such as Balsa and many coniferous species, but as we know spruce is still the standard for acoustic tops. But trust me, if it were possible to produce acoustics with Balsa or soft pine tops, it would be done, becasue that would geth the mass of the top as close to zero as possible.
Assuming SRS meant "Denser" by harder and "Less dense" by softer his generalization on tonal response is a good rule of thumb. Density and hardness are related, but not the same. One is mass, one is a surface property more than anything else
Rosewood for example is quite dense, with most of the tonal and structural properties that come with the territory, the primary reason it´s used on acoustic backs, and fingerboards. The back is unbraced and therefore needs to be able to hold it´s own, and the neck and fretboard are the most structurally taxed areas of the instrument. It´s still softer than few woods that are less dense, though, try to push your fingernail into rosewood and do the same with maple and you´ll see what I mean, the Rosewood is more likely to be scratched. The reason for rosewood´s attenuated highs compared to ebony or maple is the large amount of natural oils that stay in the wood for longer than any guitar has been around. but I´m going off on a tangent here...
It´s easy to make a structurally sound instrument some may now think, just take 20 pounds of Teak and ebony and it will ne so hard it will never collapse. And this is 100% true, but unfortunately that guitar is in reality more of a boat anchor than anything else (And considering that teak SINKS in water, that´s actually a good analogy :laugh2: )
Considering how many people have problems with a 7-8-9 pound les paul, 20-25 pounds is a bit too far on the chiropractor friendly side.
So we find ourselves forced to strike a balance between structural stability and mass reduction (Any engineers see any parallels to their daily work?
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What after a few years /decades of experimentation was found to be ideal for most purposes were woods that kept most of the density of the heavy tropical woods but with more open pores and lighter canal structures. Woods such as Mahogany, Ash, Alder and Cherry. The heavy woods stayed on as load bearers, for example in the fretboards of acoustics because back then there were no truss rods, the only thing keeping the neck straight was the dryness and preparation of hte neck combined with this ultra stable slab of ebony or rosewood glued to the top. Alder for example was very commonly used for the necks of gut strung guitars (the direct forerunners of todays nylon-strung classicals) and many still use it. Maple on the other hand would simply be structural overkill at the cost of unnecessary mass, thereby lowering responsiveness.
Many woods that are used today in electric instrument were actually more accidents than anything else. IIRC first well documentedse of Maple, basswood and Poplar for guitars was b Leo Fender, and he did not choose woods for tonal properties but used what was easy and cheap to get. He wasn´t looking to build godly tone, but an instrument that could be rapidly and effectively mass produced, would seldom require repairs and would be reliable while offering tha maximum utility. Essentially the design philosophy of the AK47 applied to a musical instrument. ...
