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The number of waves is actually the number of the vibrations causing the sound. For example, if we are
listening to a violin, it would be the number of vibrations of the· strings within a certain peri0d of time. The
higher the sound the larger- the number of vibrations per time unit; the lower the sounc_l the smaller the num-
ber. The number of vibrations within the space of one second is generally called the frequen
1
cY: and expressed
•
•
I
II d H (H
) 100H . d'
h
'b
.
h f
-d '1!Cn
f10 ' o '•
.i ,V 'tii,in, I
m units ca e
z
ertz .,
z m 1cates t at v1 rations occur at t e reyuency o
1mes per second
'\
'
.
The larger the . number of Hertz, the higher the sound. Also note that doubling the frequency of a sound
will raise it by one octave, so
we
can 'say that frequency and pitch are related logarithmically.
The range of frequencies that can be heard by the human ear depends on the individual but is generally con-
sidered to be in the approximate range of 20 Hz to 20,000 Hz.
442Hz
l
--6- 884Hz
-----221Hz
I,
:I
1 /
J1i'/f1J
(
I
. The pitch of a sound depends on the numbel-' of ~aves p' e r time r~'nit (the 'vibratio~ 'fre. q ~ency)
and becomes higher as the frequency increases.
'
1
1
·
•
•
• • 1 '
'
0
Sound Volu, m ' e
1 .... ,.., .
--The "second
bask
element
6f2iou ' r i
1
d": _· _ ._ .. ,.
If you hit a piano key forcefully, the sound will be loud. If you hit it softly, the sound will be soft. When
viewed on an oscilloscope, this change in sound volume can be seen as a difference in thi height of tbe
waves. The height of the waves is called their amplitude. The larger the amplitude the loudeli 'tl\f sou~ nd.
-- --- ti,
5,oftly
fb
l
w,,.,
Ill
h/fh,
c:;>
~
r
l '
Remember
, r - - - - - - - - - - - - - - - - - - - - - - - - - - - - ,
The sound volume is determined
oy
the
1
amplitude
1
(height
ot
a wave) - the larger the amplitude
the larger (louder) the volume.
-64-
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