These are the questions I read through before asking this:
- Guitar string - feedback from the body
- Sound due to guitar
- Waves on a guitar string
- How does an acoustic guitar amplify its sound?
- Why do harmonics occur when you pluck a string?
What I'm trying to understand (generally) is the effects of a guitar body on sound. In particular, tones being played either into the cavity or onto the face.
Here's my questions:
To what non-numerical degree are guitar bodies similar to formants? If one used a speaker to play pure tones into the cavity, would they find a meaningfully "bumpy" response? (in no way linear nor any other smooth function)
If #1 is "depends on the guitar," is this the reason for its shape and the craftsmanship involved with instrument making?
Does the non-linear response of the guitar body (and all physical bodies) create any overtones? If you took a surface transducer and played pure tones, would the non-linear response of the guitar body create any meaningful overtones?
For further insight into what I'm trying to answer, here's my intuition for the three above:
- yes there are "formants," if you tap on a guitar body, you'll hear a non-random sound. this is the frequency response.
- if you made a box guitar, the response would be even worse. the shape of guitars is such that the distance between each successive "bounce" of sound is different, so no "bounce" can get too comfortable. a box would have the same bounces in each dimension
- yes, non-linearity always introduces overtones, but given the tiny distance of movement this non-linearity is not particularly additive