What causes a note's pitch?
When you think of pitch, you think about how high or low a sound feels. The pitch of a sound is determined by the frequency of the vibrations. Frequency is how many wave cycles pass through a given point per second. The more vibrations per second, the higher the frequency and the higher the pitch. The following figure shows an example of high and low frequency:
Figure 5.2 – Frequency
The higher frequency will have a higher pitch and the lower frequency will have a lower pitch. An example of a pitch is a middle C note, which has a frequency of 261.6 Hz.
Human ears can pick up frequencies between 20 and 20,000 Hz. Hz is the unit to measure how many wave cycles pass per second. As you get older, your ears lose the ability to pick up higher-pitch sounds. Sounds that are higher than this range are called ultrasonic. Sounds that are lower are called infrasonic. Some animals can hear sounds outside of this frequency range...
