Sound

Sound is a vibration that propagates as an audible mechanical wave of pressure and displacement, through a medium such as air or water.

Frequency

The number of occurrences of a repeating oscillation per unit time. 1 hertz is 1 cycle per second.

Frequency vs Pitch…

Wavelength

The length of 1 cycle.

• 20hz wave is 17 meters long.
• 20,000hz wave is 17 millimeters long.

Amplitude

The magnitude of the wave. The difference between extreme values. DIFFERENT than volume.

Phase

Phase difference is the difference, expressed in degrees or time, between two waves having the same frequency and referenced to the same point in time.

Summing and Subtracting waves

When two waves are in phase, their amplitudes sum. If they are out of phase, their amplitudes subtract.

TERMINOLOGY

• Octave - the interval between one musical pitch and another with half or double its frequency.
• Decibel - a logarithmic scale used to measure sound level.
• Fundamental Frequency - the lowest frequency of a periodic waveform.
• Attenuation - decrease/increase in a signal. loudness.
• Gain - increase/decrease in amplitude of a signal.