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
c
Y:
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 . Al
so
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
numbe
l-
' of ~
aves
p'
er
time
r~'nit (t
he
'vibratio~ '
fre
.q~ency)
and
becomes higher
as
the
frequency
increases.
'
1
1
· • • • •
1
' '
0 Sound
Volu
,m'e
1
....
,..,
.
--The
"second
bask
element
6f2
io
u'
ri
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
th
i height of tbe
waves.
The height of the
waves
is
called
their amplitude.
The
larger
the amplitude the
loud
eli
'
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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