governing vibrations

I was once asked by a very energetic violinist if I'd make him an instrument that would 'scream like a Banshee' and I said no.
Not because I couldn't, but because to do so would be to make an instrument  disabled in other ways, and one that wouldn't live very long. You can't have maximum brightness and still produce mellow when you need it. Any extra performance in one direction will be at the cost of something else.

The vibration of strings is a bit like the government of people in some systems. The cross brace in a guitar soundboard is like the constitution, laying out the broad principles of operation and in this case it is constructed to resist the upward pull of the bridge by the strings but only as much as is deemed necessary by 'law' to facilitate the free and positive vibration of the strings.

Radiating out from the cross brace are some struts that have spheres of influence over the rest of the unsupported board. These are like the statutes and the law- their strength and shape is regulated by the maker and will have a big influence on the resonance of all parts as a unit.

It is the democratic right of the player to choose which string on which fret, and with however much intensity, the string is excited, but the string can only behave within the constraints laid down to protect the organism from getting too excited and tearing itself apart.

So that is the sort of thing a person like me thinks about when he shapes the bits that make the law of guitar.