volume or overtones

[mercy]

Its a given that the guitar doesnt have unlimited energy. Is it true that the energy can only be maximized to volume or overtones? Are both possible when building or does one have to choose which to build to?

[Alan Carruth]

A lot depends on what you mean by 'volume'. I tend to use the word 'power' to talk about the objective output; what you can measure using something like a dB meter. When I'm thinking of the subjective impression the instrument makes close up I'll say 'loudness', and 'projection' is a similar thing, but related to how far away you can get and still hear it. I'd usually take 'loudness' and 'volume' as synonyms, but you may not agree on that.

There is certainly only a limited amount of horsepower in a plucked string, but some guitars use that more efficiently than others. There are limits to this, of course, and it seems as though most 'good' guitars are working pretty close to the practical limits of efficiency anyway. This is not as surprising as it might seem, when you think about it. People have been making guitars for a long time, and guitar makers are always trying to get a little more sound out of them, so they try out new designs all the time. Most experiments fail, of course, but once in a while one succeeds. When that happens all the other makers copy it, and the change becomes par to the new standard. As a result, the designs we work with have been pretty well optimized. When that happens with any design there are two consequences:
1) the difference between the 'best' and 'average' gets to be small in objective terms, and
2) that small difference becomes very important.

So, most 'average' guitars are actually pretty good at converting string energy into sound. The ones that are not good at that are generally considered wretched.

Different designs do tend to work better in different pitch ranges, and that alters the perception of the sound. Larger guitars tend to work better in the lower range, and have a lot of fundamental in the tone. It's not that they can't be made to produce lots of overtones, just that they start out 'bass balanced', and you need to work harder to get the highs right. Smaller guitars are the other way. Since 'normal' hearing tends to be most sensitive in the higher frequency ranges the smaller guitars tend to 'project' better. Larger ones often have a strong low-end attack, which can come across as 'powerful' close up, but may not 'carry' as well at a distance.

All of this gets really complicated. Add to that the fact that everybody hears things differently, describes what they hear using different terms, and has different tastes. It keeps things 'interesting'.

[yellowesty]

To add to Alan's excellent comments, it's worthwhile to note that the human ear can, without pain or damage, detect a range of loudness that is quite incredible. At the extremes, the energy density (e.g., watts/square meter) of the loudest non-damaging sound is about one TRILLION (a million times a million) times higher than that of the softest perceivable sound. Most people have a very hard time identifying if/when the energy density of a sound they are listening to is doubled or halved. If it's increased or decreased by a factor of ten, they notice.

Because of that insensitivity to the level of energy in a sound, it doesn't take much energy in overtones (a small fraction of one percent) to dramatically change the perception of "tone."

Bottom line: there's no need to trade off tone to preserve volume.