Lesson 50: Pitch & Frequency
This lesson explains what
musical pitch "actually is", i.e.
what happens in the
physical world to make a pitch, and how we
measure pitch.
First, a brief definition of
sound:
Sound is what happens
when an
object vibrates or "shakes"; the shaking object makes the
air shake; and the shaking air makes your
ear shake. Note that
these "sound shakes" are too weak, and too fast, for your
body to
feel them, which is why we have
ears that can feel them, as
sound.
However,
not all sounds have pitch. When the air shakes back and
forth ("vibrates"), over and over,
at a constant speed, long enough
for your ear to "measure" the speed,
that's when you hear a
pitch.
Slow vibrations make "low" pitches;
fast
vibrations make "high" pitches.
A pitch is measured by its
frequency, which just means its "speed" in
vibrations per second. Vibrations-per-second is also called
Hertz; the abbreviation for
Hertz is
Hz. For example,
the pitch "A above middle C" has a
frequency of
440 Hz; that
means that it's vibrating back and forth
440 times in a second.
If you understand pitches and their frequencies, then you can go on and
learn how
a single musical tone contains multiple frequencies, in
Harmonics.
