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If the vibrations follow a periodic pattern, the sound is said to have a waveform.
The figure above shows an oscillogram—a graphical representation—of a sine wave, the
simplest and purest kind of waveform.
If the vibrations do not follow a discernible pattern, the sound is called noise.
A repetition of a waveform—each peak and trough in the oscillogram—is known as a
cycle. The number of cycles that occur per second determines the basic pitch of the
waveform—commonly known as the frequency. Most Logic Express instruments provide
a Hz (Hertz) or Frequency control that determines the number of cycles per second—and
therefore the pitch.
Tones, Overtones, Harmonics, and Partials
The frequency of a sound is known as its fundamental tone.
The waveforms of all sounds, apart from a basic sine wave, consist of the fundamental
tone and many other tones of different frequencies. Nonfundamental tones that are
whole-number multiples of the fundamental tone are known as overtones or harmonics.
Nonfundamental tones that are multiplied by fractional amounts (not whole numbers)
are called partials. A tone divided by the frequency of the fundamental tone is referred
to as a subharmonic.
• The fundamental tone is referred to as the first harmonic. This is generally louder than
the other harmonics.
348 Appendix Synthesizer Basics