<s>
In-ear	B-Device
monitors	I-Device
,	O
or	O
simply	O
IEMs	O
or	O
in-ears	O
,	O
are	O
devices	O
used	O
by	O
musicians	B-Application
,	O
audio	O
engineers	O
and	O
audiophiles	O
to	O
listen	O
to	O
music	O
or	O
to	O
hear	O
a	O
personal	O
mix	O
of	O
vocals	O
and	O
stage	O
instrumentation	O
for	O
live	O
performance	O
or	O
recording	O
studio	O
mixing	O
.	O
</s>
<s>
Second	O
,	O
while	O
floor	O
wedges	O
can	O
be	O
placed	O
in	O
front	O
of	O
a	O
particular	O
singer	O
,	O
guitarist	O
,	O
bassist	O
,	O
or	O
drummer	O
,	O
the	O
other	O
musicians	B-Application
can	O
often	O
hear	O
the	O
other	O
musicians	B-Application
 '	O
wedge	O
mixes	O
.	O
</s>
<s>
Most	O
professional	O
stage	O
in-ear	B-Device
monitor	I-Device
systems	O
use	O
wireless	O
technology	O
to	O
send	O
the	O
mix	O
to	O
the	O
IEMs	O
.	O
</s>
<s>
The	O
transmitters	O
and	O
receivers	O
transfer	O
audio	O
wirelessly	O
via	O
a	O
VHF	B-Algorithm
or	O
UHF	O
radiofrequency	O
.	O
</s>
<s>
Generally	O
speaking	O
,	O
UHF	O
systems	O
sound	O
much	O
better	O
than	O
VHF	B-Algorithm
systems	O
and	O
are	O
more	O
expensive	O
.	O
</s>
<s>
The	O
in-ear	B-Device
monitors	I-Device
themselves	O
are	O
the	O
last	O
stage	O
of	O
the	O
signal	O
path	O
in	O
the	O
system	O
.	O
</s>
<s>
If	O
a	O
universal	O
IEM	O
earpiece	B-Device
does	O
not	O
fit	O
a	O
specific	O
person	O
,	O
they	O
may	O
need	O
to	O
order	O
custom	O
in-ear	B-Device
monitors	I-Device
.	O
</s>
<s>
Depending	O
on	O
the	O
quality	O
of	O
the	O
fit	O
and	O
length	O
of	O
the	O
canal	O
portion	O
of	O
the	O
earpiece	B-Device
,	O
a	O
custom	O
fit	O
in-ear	B-Device
monitor	I-Device
will	O
generally	O
provide	O
somewhere	O
between	O
25	O
and	O
34	O
decibels	O
of	O
noise	O
reduction	O
.	O
</s>
<s>
This	O
means	O
that	O
loud	O
onstage	O
instruments	O
,	O
such	O
as	O
drum	O
kit	O
or	O
large	O
8x12	O
"	O
guitar	O
stacks	O
,	O
are	O
less	O
likely	O
to	O
cause	O
hearing	O
damage	O
for	O
onstage	O
musicians	B-Application
wearing	O
IEMs	O
.	O
</s>
<s>
Custom	O
in-ear	B-Device
monitors	I-Device
come	O
in	O
a	O
variety	O
of	O
colors	O
but	O
are	O
usually	O
clear	O
or	O
a	O
color	O
that	O
closely	O
matches	O
the	O
skin	O
color	O
of	O
the	O
performer	O
.	O
</s>
<s>
Some	O
manufacturers	O
can	O
also	O
place	O
custom	O
artwork	O
directly	O
on	O
the	O
custom	O
in-ear	B-Device
monitors	I-Device
.	O
</s>
<s>
Impressions	O
for	O
custom	O
in-ear	B-Device
monitors	I-Device
are	O
typically	O
taken	O
by	O
an	O
audiologist	O
.	O
</s>
<s>
The	O
musician	B-Application
should	O
also	O
mimic	O
their	O
embouchure	O
while	O
the	O
impression	O
material	O
is	O
setting	O
so	O
that	O
the	O
fit	O
is	O
comfortable	O
while	O
performing	O
.	O
</s>
<s>
Custom	O
in-ear	B-Device
monitors	I-Device
made	O
of	O
a	O
softer	O
silicone	O
material	O
can	O
be	O
inserted	O
deeper	O
in	O
the	O
ear	O
canal	O
and	O
will	O
provide	O
more	O
isolation	O
from	O
outside	O
noise	O
.	O
</s>
<s>
Passive	O
ambient	O
IEMs	O
have	O
a	O
small	O
hole	O
drilled	O
into	O
the	O
earpiece	B-Device
to	O
allow	O
some	O
natural	O
ambient	O
sound	O
into	O
the	O
ear	O
canal	O
.	O
</s>
<s>
This	O
can	O
potentially	O
lead	O
to	O
increased	O
sound	O
exposure	O
as	O
it	O
reduces	O
the	O
signal-to-noise	O
ratio	O
for	O
the	O
mix	O
and	O
causes	O
the	O
musician	B-Application
to	O
increase	O
the	O
levels	O
from	O
the	O
IEM	O
.	O
</s>
<s>
Television	O
studios	O
use	O
earpieces	B-Device
with	O
a	O
specialized	O
type	O
of	O
intercom	O
called	O
an	O
interruptible	O
foldback	O
(	O
IFB	O
)	O
,	O
as	O
a	O
means	O
of	O
communication	O
.	O
</s>
<s>
Originally	O
invented	O
for	O
hearing	O
aids	O
,	O
balanced	O
armature	O
drivers	O
are	O
nowadays	O
used	O
extensively	O
in	O
modern	O
in-ear	B-Device
monitors	I-Device
.	O
</s>
<s>
In-ear	B-Device
monitors	I-Device
can	O
function	O
with	O
as	O
little	O
as	O
one	O
armature	O
driver	O
but	O
some	O
of	O
the	O
top	O
models	O
of	O
in-ear	B-Device
monitors	I-Device
can	O
carry	O
as	O
many	O
as	O
18	O
balanced	O
armature	O
drivers	O
for	O
faster	O
response	O
,	O
higher	O
dynamic	O
range	O
,	O
and	O
more	O
detailed	O
sound	O
.	O
</s>
<s>
Musicians	B-Application
need	O
to	O
train	O
themselves	O
to	O
listen	O
at	O
lower	O
levels	O
to	O
take	O
full	O
advantage	O
of	O
the	O
sound	O
level	O
reduction	O
capability	O
of	O
IEMs	O
.	O
</s>
<s>
Some	O
musicians	B-Application
with	O
two	O
IEMs	O
may	O
choose	O
to	O
take	O
out	O
one	O
of	O
them	O
during	O
a	O
performance	O
to	O
hear	O
more	O
ambient	O
sound	O
.	O
</s>
