Home Frequency Pitch and Overtone Beats Instruments Works Cited


Frequency is the number of oscillations completed in one second by the wave. The symbol for frequency is f and its unit is the Hertz, (Hz). The time to complete one ocsillation, or period, is related to the frequency by:

T=1/f
Where T is the time, and f is the frequency. These sound waves also have a wavelengh, the physical distance the wave travels in one one oscillation. The wavelength is inversely proportional to the frequency of the sound wave. Wavelength is give by:
In addition to wavelength, sound waves also have an amplitude. Amplitude is the amount of air (or any other medium the sound waves are traveling through) that gets pushed with each oscillation. By now I am sure you are asking, what the heck does any of this have to do with music. Well, when this occurs as in the picture below, music is formed. We humans can hear sound waves that have a frequency between 20 Hz to 20,000 Hz. This means that any sound we hear must be in this range, hence any music produced must be in this range for us to hear it. Unless, of course, you are one of those people who believes they have "golden ears" and can hear sounds beyond the range limit. Useing our handy equations for frequency above, we can calculate that the lowest note 20 Hz, has a wavelength of around 17 meters, and the highest 20,000 Hz has a wavelength of .0017 meters. Now, an organ would need pipes with a length of about half that distance to produce notes with those frequencies. In addition to frequency there is resonance. The class example of resonance is the tuning fork. If you cause a tuning fork to vibrate, only a soft sound can be heard. However, upon placing it against a larger object that will also vibrate, the sound becames louder. The act of sound waves exciting another body into vibrating is due to resonance. If resonance is applied to the inside of a box, and the box dimensions are a multiple of the frequency, the sound waves will reinforce eachother for increased volume. This is how string instruments like the violin get loud noises from the tiny little strings. Onward to pitch and overtone.