Why Do Sounds Sound the Way They Do?
Have you ever wondered why a single person playing a single note on a
single instrument can sound so many differant ways? I have. Then I considered
the magnificent facilities you see here and realized that
I could find out the answer to that exact question. Why does a tone sound
like it does? What makes it sound "bright" or "dark"?
What makes a "good" sound?
Before I could answer these earth-shattering questions, however, I decided
to give my brain a little work-out. I decided to theorize
on my questions. The essence of what I decided is this: The color of a tone
is directly related to the numer of harmonic overtones. I thought it logical
that as a tone became "brighter" the numer of harmonics increased. I also made
an educated guess that a "good" tone was a tone that lacked "non-harmonic" or
poorly tuned harmonics. This could be caused by extraneous vibrations outside
the main vibratory system that drives the instrument.
To prove this I had several musicians come in and play notes in two ways that
are considered characteristic for their instruments. Then I had the same people
playing the same horns play in ways other than the traditional "correct" way to
play. Finally I had them play the worst sound that they could make on their horn.
To see more on the procedure press here.
While the instrumentalists had been playing, I had been busy recording the sounds
they made digitally using WavEdit for Macintosh. I used the program
to analyze the wave forms and the dominance regions of each
of the different sounds.
What I found is this. Brighter sounds have more harmonics. Worse sounds have
more harmonics as well, but they tend to have harmonics in locations other than the
expected places. More elaboration can be found here.
However, I feel that I must report any poetential errors.
So here's what I feel could be wrong with this research. Basically it comes down
to the fact that I could only find two sources to do any research from, therefore
my conclusions that have come from elaboration based on what I have read could very
easily have been biased in some way. Additionally the equipment that I had to work
with, although it certainly wasn't bad, was not the most accurate equipment on the
market. I did have some difficulty reading the graphs when a large number
of noise harmonics were on the spectrometer's display.
Assuming that the error was small enough to not damage my conclusions
significantly, here are the answers to my questions. A bright sound is made by setting
up a wave with lots of overtones, while a dark sound is one that filters out the higher
overtones. Additionally brighter tones have a significant overtone in the 3000 Hz
A bad sound is made when a large number of extra mistuned or non-harmonic overtones
interfere with the standing wave inside the horn. This can be done by creating other
waves inside the throat and lungs that are out of phase with the tuned harmonics
or adding overtones that are not normally inside the wave's system of overtones. Each
of these effects the way that we percieve sound, and confuses our ear-brain system,
much like a tunable drum. We can still discern what the pitch is supposed to be,
but we still hear interference in the tone that creates dissonance in the pitch that
we are perceiving.
In closing, even though judging the tone quality of a particular player is mostly
subjectively based on the ear of the listner, many generalities can be made. I found
that bright sounds have more overtones than dark sounds, and bad sounds tend to have
masking tones, of sorts, in the tone that they are producing.
I would like to thank Dr. Tunks for giving me the opportunity and equipment
to discover what I found. I would also like to thank the musicians that helped
me so much. Thank you Shawn, Chris, Alex, Scott, and Tommy. I owe you guys a lot.
Here's a rough diagram of this paper, complete with links.
This is my list of sources.