<s>
A	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
or	O
mid	B-Algorithm
scoop	I-Algorithm
in	O
audio	B-Algorithm
signal	I-Algorithm
processing	I-Algorithm
is	O
a	O
target	O
frequency	O
response	O
curve	O
characterized	O
by	O
boosted	O
low	O
and	O
high	O
frequencies	O
coupled	O
with	O
reduced	O
midrange	O
frequency	O
power	O
.	O
</s>
<s>
Smiley	B-Algorithm
face	I-Algorithm
curves	I-Algorithm
have	O
been	O
popular	O
with	O
some	O
car	O
audio	O
enthusiasts	O
,	O
disc	O
jockeys	O
,	O
electric	O
bass	O
players	O
,	O
home	O
stereo	O
owners	O
and	O
sound	O
reinforcement	O
operators	O
.	O
</s>
<s>
Though	O
the	O
graphic	O
equalizer	O
was	O
intended	O
to	O
tailor	O
a	O
system	O
's	O
response	O
to	O
compensate	O
for	O
venue	O
and	O
performance	O
conditions	O
,	O
the	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
is	O
sometimes	O
applied	O
as	O
a	O
purely	O
stylistic	O
effect	O
.	O
</s>
<s>
The	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
is	O
roughly	O
analogous	O
to	O
the	O
frequency	O
response	O
of	O
human	O
hearing	O
as	O
charted	O
in	O
the	O
equal-loudness	O
contour	O
,	O
and	O
has	O
been	O
compared	O
to	O
loudness	B-Algorithm
compensation	I-Algorithm
circuitry	O
in	O
that	O
it	O
increases	O
the	O
relative	O
power	O
of	O
high	O
and	O
low	O
frequencies	O
without	O
increasing	O
the	O
midrange	O
power	O
.	O
</s>
<s>
In	O
order	O
for	O
a	O
sound	O
system	O
to	O
be	O
heard	O
properly	O
by	O
humans	O
,	O
it	O
should	O
have	O
an	O
equal-loudness	O
contour	O
applied	O
to	O
it	O
when	O
it	O
is	O
performing	O
at	O
low	O
sound	O
pressure	O
levels	O
,	O
then	O
the	O
curve	O
should	O
gradually	O
flatten	O
out	O
as	O
it	O
gets	O
louder	O
.	O
</s>
<s>
The	O
origin	O
of	O
the	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
has	O
been	O
attributed	O
to	O
the	O
search	O
for	O
more	O
bass	O
and	O
treble	O
response	O
from	O
loudspeakers	O
that	O
did	O
not	O
extend	O
as	O
low	O
or	O
as	O
high	O
as	O
desired	O
,	O
especially	O
in	O
the	O
1970s	O
and	O
1980s	O
.	O
</s>
<s>
Many	O
cars	O
which	O
have	O
a	O
graphic	O
equalizer	O
have	O
been	O
observed	O
to	O
have	O
it	O
set	O
as	O
a	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
which	O
emphasizes	O
low	O
and	O
high	O
frequencies	O
.	O
</s>
<s>
A	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
can	O
indicate	O
that	O
a	O
car	O
's	O
sound	O
system	O
is	O
lacking	O
both	O
high	O
and	O
low	O
frequency	O
response	O
.	O
</s>
<s>
Various	O
compensations	O
have	O
been	O
developed	O
to	O
counteract	O
excess	O
midrange	O
response	O
in	O
the	O
instrument	O
,	O
including	O
the	O
use	O
of	O
amplifiers	O
with	O
a	O
built-in	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
and	O
amplifiers	O
that	O
offer	O
a	O
handful	O
of	O
graphic	O
equalizer	O
filters	O
so	O
that	O
the	O
user	O
can	O
make	O
the	O
necessary	O
adjustments	O
when	O
appropriate	O
.	O
</s>
<s>
Gallien-Krueger	O
makes	O
an	O
instrument	O
amplifier	O
that	O
produces	O
a	O
classic	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
in	O
its	O
default	O
voicing	O
.	O
</s>
<s>
University	O
of	O
Iowa	O
professor	O
and	O
bass	O
player	O
Dan	O
Berkowitz	O
has	O
observed	O
that	O
the	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
as	O
applied	O
to	O
bass	O
played	O
within	O
a	O
blues	O
or	O
R&B	O
band	O
can	O
make	O
it	O
hard	O
for	O
bandmates	O
to	O
play	O
off	O
the	O
bass	O
line	O
.	O
</s>
<s>
Several	O
products	O
exist	O
for	O
this	O
purpose	O
such	O
as	O
a	O
10-band	O
MXR-branded	O
equalizer	O
offered	O
by	O
Dunlop	O
Manufacturing	O
which	O
includes	O
instructions	O
for	O
a	O
"	O
Metal	O
Distortion	O
"	O
setting	O
that	O
reduces	O
1,000	O
Hz	O
,	O
a	O
midrange	O
frequency	O
,	O
down	O
to	O
its	O
maximum	O
reduction	O
point	O
,	O
with	O
nearby	O
frequencies	O
reduced	O
in	O
the	O
form	O
of	O
a	O
mid	B-Algorithm
scoop	I-Algorithm
.	O
</s>
<s>
Some	O
concert	O
sound	O
mixers	O
employ	O
the	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
as	O
a	O
tool	O
to	O
help	O
them	O
gain	O
initial	O
control	O
of	O
a	O
sound	O
system	O
.	O
</s>
<s>
Even	O
with	O
recorded	O
sound	O
,	O
the	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
has	O
its	O
backers	O
.	O
</s>
<s>
Kip	O
Bradford	O
of	O
Expert	O
Village	O
emphasizes	O
that	O
the	O
live	O
sound	O
engineer	O
must	O
not	O
employ	O
smiley	B-Algorithm
face	I-Algorithm
curves	I-Algorithm
when	O
setting	O
up	O
a	O
sound	O
reinforcement	O
system	O
.	O
</s>
<s>
Some	O
audio	O
equipment	O
manufacturers	O
have	O
accommodated	O
the	O
user	O
by	O
engineering	O
a	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
into	O
a	O
product	O
.	O
</s>
<s>
dbx	O
,	O
Inc	O
.	O
offers	O
several	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
presets	O
in	O
their	O
digital	O
graphic	O
equalizer	O
product	O
line	O
called	O
DriveRack	O
.	O
</s>
<s>
Jim	O
Dunlop	O
offers	O
a	O
direct	O
box	O
intended	O
for	O
bass	O
players	O
that	O
includes	O
a	O
preset	O
labeled	O
"	O
color	O
"	O
which	O
engages	O
a	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
.	O
</s>
<s>
Alpine	O
Electronics	O
has	O
offered	O
for	O
sale	O
a	O
product	O
for	O
car	O
audio	O
systems	O
that	O
works	O
to	O
counteract	O
any	O
smiley	B-Algorithm
face	I-Algorithm
curve	I-Algorithm
that	O
was	O
applied	O
to	O
a	O
car	O
's	O
factory	O
OEM	O
sound	O
system	O
,	O
along	O
with	O
an	O
analysis	O
feature	O
that	O
adjusts	O
for	O
road	O
and	O
vehicle	O
noise	O
.	O
</s>
<s>
Empeg	B-Application
Car	I-Application
,	O
a	O
digital	O
media	O
player	O
,	O
includes	O
a	O
"	O
Loudness	B-Algorithm
Control	O
"	O
feature	O
that	O
is	O
described	O
as	O
adding	O
a	O
"	O
smiley	O
face	O
"	O
curve	O
automatically	O
"	O
at	O
low	O
sound	O
levels	O
but	O
which	O
is	O
used	O
to	O
lesser	O
and	O
lesser	O
degrees	O
as	O
the	O
car	O
sound	O
system	O
's	O
volume	O
is	O
increased	O
.	O
</s>
<s>
This	O
describes	O
an	O
equal-loudness	O
contour	O
circuit	O
.	O
</s>
