<s>
Tone	B-Algorithm
control	I-Algorithm
is	O
a	O
type	O
of	O
equalization	O
used	O
to	O
make	O
specific	O
pitches	O
or	O
"	O
frequencies	O
"	O
in	O
an	O
audio	O
signal	O
softer	O
or	O
louder	O
.	O
</s>
<s>
A	O
tone	B-Algorithm
control	I-Algorithm
circuit	I-Algorithm
is	O
an	O
electronic	O
circuit	O
that	O
consists	O
of	O
a	O
network	O
of	O
filters	B-Architecture
which	O
modify	O
the	O
signal	O
before	O
it	O
is	O
fed	O
to	O
speakers	O
,	O
headphones	B-Device
or	O
recording	O
devices	O
by	O
way	O
of	O
an	O
amplifier	O
.	O
</s>
<s>
Tone	B-Algorithm
controls	I-Algorithm
are	O
found	O
on	O
many	O
sound	O
systems	O
:	O
radios	O
,	O
portable	O
music	O
players	O
,	O
boomboxes	O
,	O
public	O
address	O
systems	O
,	O
and	O
musical	O
instrument	O
amplifiers	O
.	O
</s>
<s>
Tone	B-Algorithm
control	I-Algorithm
allows	O
listeners	O
to	O
adjust	O
sound	O
to	O
their	O
liking	O
.	O
</s>
<s>
Tone	B-Algorithm
control	I-Algorithm
is	O
also	O
used	O
to	O
adjust	O
an	O
audio	O
signal	O
during	O
recording	O
.	O
</s>
<s>
For	O
instance	O
,	O
if	O
the	O
acoustics	O
of	O
the	O
recording	O
site	O
cause	O
it	O
to	O
absorb	O
some	O
frequencies	O
more	O
than	O
others	O
,	O
tone	B-Algorithm
control	I-Algorithm
can	O
be	O
used	O
to	O
amplify	O
or	O
"	O
boost	O
"	O
the	O
frequencies	O
the	O
room	O
dampens	O
.	O
</s>
<s>
In	O
their	O
most	O
basic	O
form	O
,	O
tone	B-Algorithm
control	I-Algorithm
circuits	I-Algorithm
attenuate	O
the	O
high	O
or	O
low	O
frequencies	O
of	O
the	O
signal	O
.	O
</s>
<s>
This	O
is	O
called	O
treble	B-Algorithm
or	O
bass	O
"	O
cut	O
"	O
.	O
</s>
<s>
The	O
simplest	O
tone	B-Algorithm
control	I-Algorithm
circuits	I-Algorithm
are	O
passive	O
circuits	O
which	O
utilize	O
only	O
resistors	O
and	O
capacitors	O
or	O
inductors	O
.	O
</s>
<s>
Active	O
tone	B-Algorithm
controls	I-Algorithm
may	O
also	O
amplify	O
or	O
"	O
boost	O
"	O
certain	O
frequencies	O
.	O
</s>
<s>
More	O
elaborate	O
tone	B-Algorithm
control	I-Algorithm
circuits	I-Algorithm
can	O
boost	O
or	O
attenuate	O
the	O
middle	O
range	O
of	O
frequencies	O
.	O
</s>
<s>
The	O
simplest	O
tone	B-Algorithm
control	I-Algorithm
is	O
a	O
single	O
knob	O
that	O
when	O
turned	O
in	O
one	O
direction	O
enhances	O
treble	B-Algorithm
frequencies	O
and	O
the	O
other	O
direction	O
enhances	O
bass	O
frequencies	O
.	O
</s>
<s>
This	O
was	O
the	O
first	O
type	O
of	O
tone	B-Algorithm
control	I-Algorithm
,	O
typically	O
found	O
on	O
radios	O
and	O
record	O
players	O
from	O
the	O
1930s	O
to	O
the	O
1970s	O
.	O
</s>
<s>
Graphic	O
equalizers	O
used	O
for	O
tone	B-Algorithm
control	I-Algorithm
provide	O
independent	O
elevation	O
or	O
attenuation	O
of	O
individual	O
bands	O
of	O
frequencies	O
.	O
</s>
<s>
Parametric	O
equalizers	O
can	O
control	O
not	O
only	O
the	O
amount	O
of	O
boost	O
and	O
cut	O
but	O
also	O
the	O
specific	O
frequency	O
at	O
which	O
the	O
boost	O
and	O
cut	O
takes	O
place	O
and	O
the	O
range	O
of	O
frequencies	O
(	O
bandwidth	B-Algorithm
)	O
affected	O
.	O
</s>
<s>
Historically	O
,	O
tone	B-Algorithm
control	I-Algorithm
was	O
achieved	O
via	O
analog	O
electronics	O
,	O
and	O
most	O
tone	B-Algorithm
control	I-Algorithm
circuits	I-Algorithm
produced	O
today	O
still	O
use	O
the	O
analog	O
process	O
.	O
</s>
<s>
Nonetheless	O
,	O
digital	O
approaches	O
are	O
increasingly	O
being	O
implemented	O
through	O
the	O
use	O
of	O
digital	B-General_Concept
signal	I-General_Concept
processing	I-General_Concept
.	O
</s>
