timtam wrote: ↑Sat Dec 17, 2022 7:20 pm
Highnumbers wrote: ↑Sat Dec 17, 2022 10:58 am
There is a world of difference between people waxing on about “tonewoods” and a basic understanding that the density of certain woods has a minor effect on the sound. Even on a solidbody.
Whether or not you agree with this is another matter altogether. But let’s not flame those who have firsthand experience testing this out, while others are just reading about it online and making “scientific” claims.
It's worth saying that the guitar science literature presents a consistent picture of the physics of real solid body electric guitars - a significant body of work by independent (guitar-playing) scientists, on different guitars, using a range of different scientific methods, in different labs, over several decades. All pointing to similar, consistent conclusions. The results of that work is entirely consistent with everyone's real
heard experience of guitars - just not always the ‘explanations’ for that heard experience that some people dreamed up.
Of course the material properties of wood affects way that vibrations pass through it, as they do for any material. But that falls far short of meaning that those properties are relevant in a real solid-body electric guitar. The actual research has shown that the long, thin, flexible, composite neck (neck wood, fretboard wood, truss rod, headstock) in real guitars has a sonic role. There is little evidence that the solid
body has any any similar role. They are of course very different physical structures.
A large part of the evidence against the likelihood of any significant sonic role for solid
body wood is that a
mechanism does not obviously exist for it to play a significant role. Despite what some players believe, little vibration actually reaches the body from the strings. Bridge admittance (conductance) of real guitars is measured as very small, much smaller than that of the neck (where it can be significant). Direct measurements of body vibration also show that very little vibration reaches the body. Direct measurements of the proportion of string vibrations excited by the pick that remain in the strings show that the overwhelming proportion do so - unlike in an acoustic guitar. And direct sustain measurements show it to be much better than in acoustic guitars. Sustain has also been accurately predicted just from the neck's resonant modal frequencies and the string's properties. Together all that indicates that significant vibration energy cannot be leaving the strings.
So all in all, we have a panel of measurements from real guitars that consistently supports the contention that body vibration is not significant. So if little vibration ever reaches the body, the material properties of different solid body wood species, or even just different
pieces of solid wood, has no real
mechanism to significantly and variably affect the sonic output of the guitar.
Is it possible that one day we might still see an unequivocal, consistent measurement of a sonic effect of solid-body wood ? Of course. But the ‘bar’ of existing evidence is high. As it stands, all of the anecdotes or poorly controlled, supposed 'demonstrations' of solid wood effects are at least consistent with another important set of findings from the guitar science research - that there are many, many things that can
sometimes (but not
always) affect the sonic output of real solid body guitars. Many more than was once thought, and many not widely known by players (see for example ch7 of Zollner's "Physics of the Electric Guitar"). So just showing that two guitars made of different solid woods - that appear otherwise
nominally similar - sound different unfortunately falls far short of evidence that solid wood is sonically important. To prove that, one would need to make a lot of exacting measurements to be sure that none of the other many factors varied between those two guitars, or measure enough samples of the same woods that any consistent sonic effect of the wood would emerge from the 'noise' of the other potentially sonically-influential factors.
How then do some players say how much they can feel the body vibrating ? Well the skin mechanoreceptors via which we feel vibrations are very sensitive (but only to a rather narrow band of low frequencies; other frequencies are not felt at all). So it's easy for some players to convince themselves that the solid body is vibrating much more than it is. Especially given the echo chamber of famous players, guitar journalists, and guitar manufacturers who have been reinforcing and embellishing such misunderstandings of guitar physics for some decades. With the possible exception of one (non-US) manufacturer, none of the major electric guitar manufacturers do any guitar physics work (some acoustic manufacturers do some). And I have seen no evidence that they are even aware of the work done elsewhere. Admittedly, most of the work has been done in Europe (mainly in Germany and France), and some of the most important work has only been translated into English in recent years. But guitar manufacturers don’t employ such scientists, because you can build great guitars without a full understanding of their real physics.
Furthermore, when some players say "the body really resonates", as if it's obviously a "good" thing, they are basically failing to understand the Conservation of Energy Law. If the body
were vibrating at a particular frequency due to energy from string vibrations, the strings would no longer be vibrating at that frequency - those vibrations would be
lost from the strings. So not obviously a 'good' thing (the related notion of 'transfer of vibrations to the body' as a good thing is similar physics nonsense). Paul Reed Smith's notion of the "subtractive" nature of guitars is one thing about guitar physics he gets right. Of course you might subjectively "like" the sound of a guitar with a particular set of such losses (which have been measured as mostly to the neck and the bridge's internal vibrations). But once vibration energy at a particular frequency has been lost from the strings, you can't get it back.
Sure some guitars are ‘really resonant' as players say. But it's because most vibrations are remaining in the strings. That’s what they’re hearing. Some of that can be heard acoustically, but the acoustic sound is also mediated by other things that make it a less-than-ideal predictor of the amplified sound; which of course is also heavily influenced by the pickups (whose individual frequency response is not supplied by manufacturers, so we are usually just guessing about their sonic variability due to manufacturing variations) and the rest of the signal chain.
I've cited some of the published guitar science work that supports this overall picture elsewhere in this thread. But happy to supply more.
