How does something like physics apply to sound and how can wood affect it?

[PRSpoggers]

I'm not trying to start a tone wood debate (I believe that yes wood does affect tone but we are NOT! getting into a debate) but I was merely observing something like acoustic instruments and how their bracing is carved and how that affects the tone sonically. How does wood and sound and physics work together? Would getting rid of material dampen tone or take away from it? Or would the way you carve a bracing one certain way will affect the sonic capabilities of it? I know there are so many things to take into account as a luthier and carving wood, but what affects the wood and tone?

[Bizman62]

In acoustic instruments tonewood is a fact. The sound of the strings is amplified and targeted inside the hollow body and the construction can either amplify or dampen certain frequences. The shape of the body, the size of the sound hole, the thickness of the top, bottom and sides,  the size and shape of braces all have their impact to the final output.

In solidbody electric instruments the wood choice doesn't affect that much as magnetic pickups only register the vibration of the strings. As you say, the wood used affects tone but it does that indirectly. Rather than actual tone it's about sustain i.e. how long the neck and body maintain the vibration of the strings. Strummed strings make the body vibrate as well which in turns makes the strings vibrate which makes the body vibrate etc. until the energy runs out. It's similar to a pendulum: You push it one way and it swings back the other way almost the same amount and continues that back and forth movement in decreasing arcs until it stops. If you shorten the pendulum arm the swinging motion gets denser and I guess that the wood choice can have a similar effect to the frequency response.

7 hours ago, PRSpoggers said:

Would getting rid of material dampen tone or take away from it?

It affects to the frequency. Xylophones and the likes are tuned by taking material off the bars. Sanding a bar thinner in the middle of the bottom side tunes it down, sanding both ends shorter tunes it up. You can tune the top of an acoustic guitar by shaping the bracing. A common rule seems to be that tapping the top in various spots should give as many different sounds as possible for the most balanced and richest output.

[Crusader]

15 hours ago, PRSpoggers said:

....How does wood and sound and physics work together?....

This might also help explain what you're asking about

On one of my semi-accoustics I made a type of "post" (like a violin has) to strengthen the top. I experimented and when its out the tone is much deeper

When the post is in it stops the top and back from vibrating in full length. Something like doing a harmonic at the 12th fret, where the whole string is vibrating but you only hear the octave because its vibrating in two halves. When luthiers put bracing in a top or back it limits the modes of vibrations in much the same way but its a lot more complicated

[Workingman]

Basically wood absorbs or transmits vibrations according to its size, shape, density and internal cellular structure.  How these things interact in a single piece of wood can be complicated.  How they interact in the multiple pieces of wood used in a musical instrument is incredibly complex.  There have been dozens if not hundreds of attempts to study what physical properties make for the best instruments.  They have been largely inconclusive.  To date the experience of a good instrument builder tends to produce the best instruments.  their have been collaborations between scientists and instrument builders that have yielded interesting results.  One of the. most successful has been the pianos by the Italian company Faziolli.  

[Andyjr1515]

There's a video I've posted in the past that would probably answer all your questions.  I'll track it down and repost in the morning