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Old 09-30-2012, 08:58 AM
defenestrate defenestrate is offline
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Join Date: Sep 2012
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Originally Posted by KenW View Post
I'll try to do that, hesson.

Concerning back resonance, there is a thought gaining ground that backs that freely vibrate results in the guitar's sound being more resonant up close, but in the big picture a freely vibrating back actually -robs- the energy of the soundwave's projection. Big splash with little travel. It would be an easy experiment to conduct if a pair of people could get a decent classical guitar into a large room and take turns listening and playing, alternating with the back against the chest and with it off.

There are well respected luthiers that laminate their backs and sides to intentionally make them more rigid, thinking that will force more of the string's energy to the top.
Right. being that sound waves are coordinated variances in pressure when in open air, a back that vibrates heavily will tend to move in approximate unison with the top, which might be good for certain kinds of recording, but much like closing a door in a house, the net volume of air changes far less. at certain frequencies, in certain conditions of humidity and air pressure, this could create certain frequencies that have a synergistic effect and hence a peak in the frequency, but for projection, you want as much air on the outside of the instrument carrying this energy as possible, and the most reliable way to do that is to have a very resonant top constantly pushing and pulling this air, most effectively through the soundhole. (I'm sure you know this, but it may not seem intuitive to folks who feel more vibration in the guitar from the sympathetic resonance of back and sides).
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