<s>
A	O
mid-range	B-Device
speaker	I-Device
is	O
a	O
loudspeaker	O
driver	O
that	O
reproduces	O
sound	O
in	O
the	O
frequency	O
range	O
from	O
250	O
to	O
2000	O
Hz	O
.	O
</s>
<s>
Mid-range	B-Device
drivers	I-Device
are	O
usually	O
cone	O
types	O
or	O
,	O
less	O
commonly	O
,	O
dome	O
types	O
,	O
or	O
compression	O
horn	O
drivers	O
.	O
</s>
<s>
Cone	O
mid-range	B-Device
drivers	I-Device
typically	O
resemble	O
small	O
woofers	B-Device
.	O
</s>
<s>
The	O
most	O
common	O
material	O
used	O
for	O
mid-range	O
cones	O
is	O
paper	O
,	O
occasionally	O
impregnated	O
and/or	O
surface-treated	O
with	O
polymers	B-Language
or	O
resins	B-Language
in	O
order	O
to	O
improve	O
vibrational	O
damping	O
.	O
</s>
<s>
Other	O
mid-range	O
cone	O
materials	O
include	O
plastics	O
such	O
as	O
polypropylene	O
,	O
Cobex	O
,	O
Bextrene	O
,	O
woven	O
Kevlar	O
,	O
fiberglass	O
,	O
carbon	O
fiber	O
,	O
or	O
light	O
metal	O
alloys	B-Application
based	O
on	O
aluminium	O
,	O
magnesium	O
,	O
titanium	O
,	O
or	O
other	O
alloys	B-Application
.	O
</s>
<s>
Most	O
professional	O
concert	O
mid-range	B-Device
drivers	I-Device
are	O
compression	B-Device
drivers	I-Device
coupled	O
to	O
horns	B-Device
.	O
</s>
<s>
A	O
very	O
few	O
mid-ranges	B-Device
are	O
electrostatic	O
drivers	O
,	O
planar	O
magnetic	O
drivers	O
,	O
or	O
ribbon	O
drivers	O
.	O
</s>
<s>
A	O
mid-range	B-Device
driver	I-Device
is	O
called	O
upon	O
to	O
handle	O
the	O
most	O
significant	O
part	O
of	O
the	O
audible	O
sound	O
spectrum	O
,	O
the	O
region	O
where	O
the	O
most	O
fundamental	O
frequencies	O
are	O
emitted	O
by	O
musical	O
instruments	O
,	O
and	O
,	O
most	O
importantly	O
,	O
the	O
human	O
voice	O
,	O
lie	O
.	O
</s>
<s>
It	O
is	O
therefore	O
paramount	O
that	O
a	O
mid-range	B-Device
driver	I-Device
of	O
good	O
quality	O
be	O
capable	O
of	O
low-distortion	O
reproduction	O
.	O
</s>
<s>
Most	O
television	O
sets	O
and	O
small	O
radios	O
have	O
only	O
a	O
single	O
mid-range	B-Device
driver	I-Device
,	O
or	O
two	O
for	O
stereo	O
sound	O
.	O
</s>
<s>
Mid-range	B-Device
drivers	I-Device
are	O
usually	O
used	O
in	O
three	O
way	O
multi	O
driver	O
speaker	O
systems	O
.	O
</s>
<s>
There	O
are	O
therefore	O
special	O
considerations	O
involved	O
in	O
the	O
acoustic	O
join	O
between	O
the	O
mid-range	O
and	O
both	O
the	O
low	O
frequency	O
(	O
woofers	B-Device
)	O
and	O
the	O
high	O
frequency	O
drivers	O
(	O
tweeters	B-Device
)	O
.	O
</s>
<s>
The	O
nature	O
of	O
the	O
drivers	O
on	O
both	O
sides	O
of	O
the	O
mid-range	O
,	O
and	O
the	O
mid-range	O
itself	O
affect	O
the	O
selection	O
of	O
crossover	B-Algorithm
frequency	I-Algorithm
and	O
slope	O
.	O
</s>
<s>
Nearly	O
all	O
crossovers	B-Algorithm
are	O
passive	O
circuits	O
,	O
designed	O
to	O
match	O
the	O
characteristics	O
of	O
the	O
drivers	O
and	O
their	O
mounting	O
,	O
and	O
are	O
built	O
of	O
capacitors	O
,	O
inductors	O
,	O
and	O
resistors	O
.	O
</s>
<s>
Active	O
or	O
'	O
electronic	O
 '	O
crossovers	B-Algorithm
are	O
used	O
in	O
some	O
high	O
performance	O
hi-fi	O
speakers	O
,	O
and	O
in	O
professional	O
sound	O
reinforcement	O
systems	O
.	O
</s>
<s>
Placement	O
of	O
the	O
mid-range	O
(	O
and	O
tweeter	B-Device
)	O
drivers	O
on	O
the	O
enclosure	O
baffle	O
significantly	O
affects	O
the	O
output	O
of	O
the	O
driver	O
,	O
and	O
the	O
material	O
surrounding	O
the	O
mid-range	O
and	O
tweeter	B-Device
drivers	O
on	O
the	O
baffle	O
can	O
produce	O
(	O
or	O
inhibit	O
)	O
reflections	O
of	O
energy	O
from	O
the	O
baffle	O
face	O
,	O
or	O
other	O
items	O
,	O
further	O
influencing	O
the	O
output	O
.	O
</s>
<s>
When	O
a	O
mid-range	B-Device
speaker	I-Device
is	O
mounted	O
in	O
the	O
same	O
box	O
as	O
a	O
woofer	B-Device
,	O
it	O
will	O
have	O
its	O
own	O
small	O
sub-enclosure	O
,	O
or	O
a	O
sealed	O
back	O
,	O
to	O
prevent	O
the	O
woofer	B-Device
's	O
backwave	O
radiation	O
into	O
the	O
box	O
from	O
affecting	O
the	O
mid-range	O
'	O
s	O
cone	O
or	O
dome	O
motion	O
.	O
</s>
