The Record Producer
Page 63
Chapter 5
The all encompassing reality of wave relationships.
Secondary description: OMNI-PHASE; an all-inclusive illustration
of the many ways compression waves affect each other.

Sine waves are a warm a fuzzy visual aid. Barely experienced digital
producers no that waveform is always much more complex. Phase
problems may present themselves, in engineering circumstances.
There are several ways to remedy these problems, but the best
thing to do is prevent them before they are recorded. This is
accomplished by training your ears to recognize them. Therefore,
we will begin with the engineer's understanding of speaker phase
and microphone phase. Then we will relate it to NFR. An
understanding of omni-phase will separate the men form the boys,
as independent producers grow through the coming decades.

Phase distortion is measured in degrees. As a speaker generates
compression waves, its drivers move in two directions: forward and
backward, or positive and negative. Behind a driver is a coil that
acts as an electromagnet. As you know, if you have ever played with
a driver, its outside edges are affixed while the cone can move freely
inward or outward. When the magnet becomes charged by an
incoming signal, it either attracts or repels the cone. When it repels,
the cone moves forward or positively, creating the beginnings of a
compression wave. The air molecules in front of the driver are
pushed together and wave energy begins to travel away from the
speaker at 340.29 m/s. When the magnet attracts the speaker, the
cone moves backward or negatively. This spreads the air molecules
farther apart. Negative wave energy is still energy and part of the
compression wave. It too travels away from the driver 340.29 m/s.