5.13 Other primary vibrators
You saw in the previous two sections that stringed instruments and wind instruments possess primary vibrators that have harmonically related natural frequencies. As a result, these two classes of instruments produce notes that have a well-defined sense of pitch.
In this section, I want to briefly introduce you to some primary vibrators that don't have harmonically related natural frequencies. Specifically we shall take a look at a rectangular bar, a circular membrane and a circular plate. These primary vibrators are often found in percussion instruments, many of which produce notes without a well-defined sense of pitch. For example, the primary vibrator in a cymbal is a circular plate and the primary vibrator in a snare drum is a circular membrane. Neither of these instruments produces notes that have a very definite pitch.