<s>
A	O
boundary	B-Algorithm
microphone	I-Algorithm
(	O
or	O
pressure	O
zone	O
microphone	O
)	O
is	O
one	O
or	O
more	O
small	O
omnidirectional	O
or	O
cardioid	O
condenser	O
mic	O
capsule(s )	O
positioned	O
near	O
or	O
flush	O
with	O
a	O
boundary	O
(	O
surface	O
)	O
such	O
as	O
a	O
floor	O
,	O
table	O
,	O
or	O
wall	O
.	O
</s>
<s>
The	O
boundary	B-Algorithm
microphone	I-Algorithm
can	O
be	O
used	O
as	O
a	O
piano	O
mic	O
by	O
placing	O
it	O
inside	O
the	O
piano	O
lid	O
,	O
an	O
approach	O
which	O
can	O
obtain	O
better	O
pickup	O
of	O
the	O
piano	O
's	O
mix	O
of	O
sharp	O
percussive	O
transients	O
and	O
gentle	O
undertones	O
than	O
other	O
microphone	O
options	O
.	O
</s>
<s>
reverberation	O
)	O
,	O
a	O
boundary	B-Algorithm
microphone	I-Algorithm
prevents	O
phase	O
interference	O
between	O
direct	O
and	O
reflected	O
sound	O
,	O
resulting	O
in	O
a	O
natural	O
sound	O
with	O
a	O
flatter	O
frequency	O
response	O
than	O
can	O
be	O
obtained	O
with	O
a	O
stand-mounted	O
microphone	O
at	O
the	O
same	O
distance	O
(	O
explanation	O
below	O
)	O
.	O
</s>
<s>
By	O
placing	O
the	O
diaphragm	O
of	O
the	O
microphone	O
capsule	O
parallel	O
to	O
and	O
facing	O
the	O
plate	O
boundary	O
provided	O
by	O
the	O
microphone	O
package	O
,	O
the	O
reflected	O
sound	O
delay	O
is	O
reduced	O
,	O
and	O
the	O
resulting	O
comb	B-Algorithm
filter	I-Algorithm
interference	O
frequencies	O
are	O
high	O
enough	O
that	O
they	O
are	O
outside	O
the	O
audible	O
range	O
.	O
</s>
<s>
The	O
terms	O
"	O
boundary	B-Algorithm
microphone	I-Algorithm
"	O
and	O
"	O
pressure	O
zone	O
microphone	O
"	O
(	O
or	O
PZM	B-Algorithm
)	O
refer	O
to	O
the	O
same	O
general	O
design	O
.	O
</s>
<s>
PZM	B-Algorithm
is	O
a	O
trademarked	O
by	O
Crown	O
.	O
</s>
<s>
Radio	O
Shack	O
and	O
Tandy	O
also	O
use	O
the	O
PZM	B-Algorithm
term	O
for	O
their	O
particular	O
design	O
of	O
a	O
boundary	O
mic	O
,	O
in	O
which	O
the	O
condenser	O
capsule	O
was	O
positioned	O
slightly	O
higher	O
than	O
the	O
base	O
plate	O
.	O
</s>
<s>
One	O
1986	O
source	O
uses	O
the	O
alternate	O
term	O
"	O
barrier	O
microphone	O
"	O
to	O
refer	O
to	O
the	O
boundary	B-Algorithm
microphone	I-Algorithm
approach	O
.	O
</s>
<s>
Since	O
one	O
of	O
the	O
benefits	O
of	O
boundary	B-Algorithm
microphones	I-Algorithm
is	O
that	O
they	O
are	O
less	O
visually	O
obtrusive	O
,	O
they	O
may	O
be	O
available	O
in	O
several	O
colors	O
,	O
to	O
enable	O
audio	O
engineers	O
to	O
select	O
the	O
color	O
that	O
will	O
blend	O
best	O
with	O
the	O
surface	O
they	O
will	O
be	O
placed	O
on	O
or	O
mounted	O
on	O
,	O
in	O
order	O
to	O
further	O
reduce	O
the	O
mic	O
's	O
visual	O
obtrusiveness	O
.	O
</s>
<s>
Sanken	O
's	O
CUB-01	O
boundary	B-Algorithm
microphone	I-Algorithm
has	O
a	O
32mm	O
diameter	O
and	O
12mm	O
height	O
,	O
which	O
makes	O
it	O
easier	O
to	O
hide	O
in	O
TV	O
and	O
film	O
field	O
shooting	O
and	O
easier	O
to	O
reposition	O
or	O
temporarily	O
mount	O
in	O
locations	O
(	O
e.g.	O
</s>
<s>
The	O
Crown	O
PZM-30D	O
has	O
a	O
switchable	O
filter	O
that	O
allows	O
you	O
to	O
switch	O
between	O
a	O
flat	O
response	O
or	O
a	O
“	O
brighter	O
”	O
sound	O
.	O
</s>
<s>
Gold	O
Line	O
's	O
CBM1	O
boundary	B-Algorithm
microphone	I-Algorithm
and	O
Crown	O
's	O
"	O
Sound	O
Grabber	O
II	O
"	O
have	O
an	O
internal	O
battery	O
to	O
power	O
the	O
condenser	O
.	O
</s>
<s>
Schoeps	O
 '	O
BLM	O
3	O
boundary	B-Algorithm
microphone	I-Algorithm
is	O
unusual	O
in	O
that	O
it	O
has	O
a	O
"	O
pressure	O
transducer	O
"	O
capsule	O
that	O
provides	O
a	O
hemispherical	O
pickup	O
pattern	O
.	O
</s>
<s>
A	O
directional	O
boundary	B-Algorithm
microphone	I-Algorithm
is	O
a	O
boundary	B-Algorithm
microphone	I-Algorithm
with	O
a	O
directional	O
polar	O
pattern	O
such	O
as	O
cardioid	O
or	O
supercardioid	O
.	O
</s>
<s>
The	O
predecessor	O
of	O
the	O
directional	O
boundary	B-Algorithm
microphone	I-Algorithm
was	O
a	O
directional	O
microphone	O
placed	O
in	O
an	O
Electrovoice	O
Mic	O
Mouse	O
,	O
a	O
foam	O
block	O
that	O
suspended	O
a	O
conventional	O
microphone	O
horizontally	O
just	O
above	O
a	O
surface	O
.	O
</s>
