Random Link: - Jon Irenicus, Baldur's Gate II.
Here the results of some guitar experiments are described. Most of the experiments were changes of guitar physics. The main goal was getting a thicker, richer string tone for a fatter overdrive. The goal was achieved, but along the way a lot of curious test results has surfaced.
First of all, when someone starts drivelling about how all electric guitars sound the same and the only part that matters is pickups, you're either dealing with a fame vampire (you know, the kind that gets off on drawing attention) or an utter cretin. This is because anything, even paint, on an electric guitar will change its tone.
The physics are simple: what you have is basically a wooden board with a wooden stick and strings attached with bits of metal. Strings are attached via the bridge/saddles/nut/tuners. The stick (neck really) is typically bolted on, but it can go through the body (neck-through), in which case joint rigidity improves a lot, improving strings/neck/body connection a lot, thus making the string tone a lot tighter and fuller!
So what you have is the vibration acoustics of a board and stick with strings attached.
The essential mechanism is this: strings fire into the body, body starts vibrating, and this vibration fires back into strings, altering the strings' tone as well. The only bloody way in which a guitar produces a 100% string tone is when it's made of stone or lead and built into the ground. Otherwise its tone is defined by the wood, mostly neck and fretboard and (surprise) nut, the remainder by the body and (important bit) body mechanical impedance. Strings and pick also matter, of course - some strings (nickel-plated/nickel compounds) are darker than others (stainless steel, cryogenic), and plastic picks are darker and duller than various metals.
Mechanical impedance is crucial for understanding how an electric guitar tone will change. Mechanical impedance (in this case) is simply how much of an obstacle the guitar is to strings. Higher mechanical impedance means the strings will not be capable of moving the body as much, therefore focusing string tone (though not necessarily the right way). Lower mechanical impedance translates into a blurrier, less focused tone and more body tone.
Wood resonance matters as harder woods have a higher impedance, whereas softer woods have a lower impedance. So a birch guitar will have a brighter, more powerful and much more focused tone than a basswood guitar (much the same as drums). Mahogany is darker and less focused than maple, as another example. Its impedance is lower, so strings go looser and more string energy is soaked by the wood. Maple will therefore be more resonant in higher midrange and treble with a more focused tone than mahogany.
The basic concept is: harder wood, more mechanical impedance=more powerful, focused and more string tone; softer wood, less mechanical impedance=looser, warmer, woodier tone. This can be varied in any way though: a neck-through mahogany guitar can combine a warm, darkish tone with a more focused string tone, say. Larger guitar body will also produce more wood resonance (more precisely, longer, bassier vibrofeedback waves), though ironically a thicker neck might be more effective in giving a richer, warmer woody tone.
A stone guitar built into a stone floor will have a nearly infinite mechanical impedance, giving an ultra-pure and possibly tinnish string tone. This is because the warmth in a guitar's tone is mostly wood.
The trick - and this is the funny bit - is that softer woods can be optimised to get more acoustic impedance out of them simply by sticking anti-vibration materials on. There is a bunch of those out on the market: Dynamat, Blu-tack, and various metal tapes (steel might be the best, but copper and aluminium also works). This is a process well-known to headphone/speaker modders: damping. Metal tapes are also good for shielding, so a single roll is good for both purposes.
Damping can turn a slow, hard-to-play guitar into something reasonably fast, focused, and concise.
A previously mediocre guitar.
It plays like this:
So other than swapping pickups, increasing body rigidity in the key spots helps. Simply put, sticking Dynamat and metal tape where it matters. The key spots are: neck joint (string focus/power), tail (bottom of the guitar below the bridge), and neck. Damping tail is better than damping neck, and will improve neck speed/responsiveness/focus by damping tail vibration, which might be blurring the tone. Damping neck is a bit tricky: too much damping will make it dead. A single thin strip of copper or steel or aluminium tape is usually enough. An overdampened neck will suck all 3D volume out of tone. The acoustic-like woody tunnel part of a guitar's tone is mostly neck/fretboard. Coating the fretboard and neck with, say, copper tape will kill whichever 3Dish woody fullness a guitar has. This is why neck and fretboard material is crucial for note clarity and tracking: the neck is the part that gives an electric guitar its woody volume, much like a resonant hole in an acoustic (though less spacey). Neck material (and damping) also matters for how fast and accurate the guitar can be played overdriven. Fretboard defines fullness and resonance on attack, also tracking accuracy (as usual, harder woods are more accurate, which is why ebony is considered a better material than rosewood).
Speaking of which, a guitar can be overdampened, in which case it'll get a very metallic, somewhat tinny (when played clean) tone with next to no wood/warmth in it. And that is one of the few cases when wood isn't too noticeable; in fact, it's a good way of figuring out the importance of wood in electric guitar sound - simply overdampen the silly thing into oblivion and puke at how dead and tinny it plays... You can peel the metal tape off later.
Pickups matter too, but before even going into pickups, rewiring and changing capacitors can also improve tone. In the very least it can speed things up and make a guitar more responsive. See the other article on that.