<s>
There	O
are	O
a	O
number	O
of	O
well-developed	O
microphone	B-Algorithm
techniques	I-Algorithm
used	O
for	O
recording	O
musical	O
,	O
film	O
,	O
or	O
voice	O
sources	O
or	O
picking	O
up	O
sounds	O
as	O
part	O
of	O
sound	O
reinforcement	O
systems	O
.	O
</s>
<s>
Situational	O
circumstances	O
:	O
Sometimes	O
a	O
microphone	B-Application
should	O
not	O
be	O
visible	O
,	O
or	O
having	O
a	O
microphone	B-Application
nearby	O
is	O
not	O
appropriate	O
.	O
</s>
<s>
In	O
scenes	O
for	O
a	O
movie	O
the	O
microphone	B-Application
may	O
be	O
held	O
above	O
the	O
pictureframe	O
,	O
just	O
out	O
of	O
sight	O
.	O
</s>
<s>
In	O
this	O
way	O
there	O
is	O
always	O
a	O
certain	O
distance	O
between	O
the	O
actor	O
and	O
the	O
microphone	B-Application
.	O
</s>
<s>
There	O
are	O
several	O
classes	O
of	O
microphone	B-Application
placement	O
for	O
recording	O
and	O
amplification	O
.	O
</s>
<s>
In	O
close	O
miking	B-Application
,	O
a	O
microphone	B-Application
is	O
placed	O
relatively	O
close	O
to	O
an	O
instrument	O
or	O
sound	O
source	O
,	O
within	O
three	O
to	O
twelve	O
inches	O
,	O
producing	O
a	O
dry	O
or	O
non-reverberant	O
sound	O
.	O
</s>
<s>
Close	O
miking	B-Application
often	O
affects	O
the	O
frequency	O
response	O
of	O
the	O
microphone	B-Application
,	O
especially	O
for	O
directional	O
mics	O
which	O
exhibit	O
bass	O
boost	O
from	O
the	O
proximity	O
effect	O
.	O
</s>
<s>
In	O
ambient	O
or	O
distant	O
miking	B-Application
,	O
a	O
microphone	B-Application
—	O
typically	O
a	O
sensitive	O
one	O
—	O
is	O
placed	O
at	O
some	O
distance	O
from	O
the	O
sound	O
source	O
.	O
</s>
<s>
In	O
room	O
miking	B-Application
a	O
distant	O
mic	O
,	O
referred	O
to	O
as	O
the	O
room	O
mic	O
,	O
is	O
used	O
in	O
conjunction	O
with	O
a	O
close	O
mic	O
,	O
"	O
typically	O
placed	O
far	O
enough	O
past	O
the	O
critical	O
distance	O
in	O
a	O
room	O
that	O
the	O
room	O
's	O
ambience	O
and	O
reverberations	O
transduce	O
at	O
an	O
equivalent	O
,	O
if	O
not	O
greater	O
,	O
volume	O
than	O
the	O
sound	O
source	O
itself.	O
"	O
</s>
<s>
Accent	O
(	O
or	O
spot	O
)	O
microphone	B-Application
placement	O
.	O
</s>
<s>
A	O
microphone	B-Application
that	O
has	O
been	O
placed	O
within	O
a	O
reasonably	O
close	O
range	O
to	O
an	O
instrument	O
or	O
section	O
within	O
a	O
larger	O
ensemble	O
(	O
but	O
not	O
so	O
close	O
as	O
to	O
have	O
an	O
unnatural	O
sound	O
)	O
is	O
known	O
as	O
an	O
accent	O
(	O
or	O
spot	O
)	O
pickup	O
.	O
</s>
<s>
Whenever	O
accent	O
miking	B-Application
is	O
used	O
,	O
care	O
should	O
be	O
exercised	O
in	O
placement	O
and	O
pickup	O
choices	O
.	O
</s>
<s>
Instrumental	O
use	O
of	O
microphones	B-Application
has	O
been	O
developed	O
by	O
many	O
experimental	O
composers	O
,	O
musicians	O
and	O
sound	O
artists	O
.	O
</s>
<s>
They	O
use	O
microphones	B-Application
in	O
unconventional	O
ways	O
,	O
for	O
example	O
by	O
preparing	O
them	O
with	O
objects	O
,	O
moving	O
them	O
around	O
or	O
using	O
contact	O
microphones	B-Application
to	O
colour	O
the	O
sound	O
and	O
be	O
able	O
to	O
amplify	O
otherwise	O
very	O
silent	O
sounds	O
.	O
</s>
<s>
Karlheinz	O
Stockhausen	O
used	O
microphone	B-Application
movements	O
by	O
musicians	O
in	O
Mikrophonie	O
I	O
to	O
discover	O
the	O
diverse	O
sounds	O
of	O
a	O
big	O
tam-tam	O
and	O
Pauline	O
Oliveros	O
amplified	O
apple	O
boxes	O
with	O
contact	O
microphones	B-Application
.	O
</s>
<s>
Parabolic	O
microphones	B-Application
are	O
used	O
to	O
capture	O
sounds	O
on	O
the	O
field	O
during	O
football	O
games	O
.	O
</s>
<s>
Often	O
each	O
instrument	O
or	O
vocalist	O
is	O
miked	O
separately	O
,	O
with	O
one	O
or	O
more	O
microphones	B-Application
recording	O
to	O
separate	O
channels	O
(	O
tracks	O
)	O
.	O
</s>
<s>
Microphones	B-Application
may	O
also	O
be	O
used	O
to	O
record	O
the	O
overall	O
effect	O
,	O
or	O
just	O
the	O
effect	O
of	O
the	O
performance	O
room	O
.	O
</s>
<s>
These	O
are	O
the	O
relative	O
level	O
(	O
or	O
loudness	O
)	O
difference	O
between	O
the	O
two	O
channels	O
Δ	O
L	O
,	O
and	O
the	O
time	O
delay	O
difference	O
in	O
arrival	O
times	O
for	O
the	O
same	O
sound	O
in	O
each	O
channel	O
Δ	O
t	O
.	O
The	O
"	O
interaural	O
"	O
signals	O
(	O
binaural	O
ILD	O
and	O
ITD	O
)	O
at	O
the	O
ears	O
are	O
not	O
the	O
stereo	O
microphone	B-Application
signals	O
which	O
are	O
coming	O
from	O
the	O
loudspeakers	O
,	O
and	O
are	O
called	O
"	O
interchannel	O
"	O
signals	O
( Δ	O
L	O
and	O
Δ	O
t	O
)	O
.	O
</s>
<s>
Here	O
there	O
are	O
two	O
directional	O
microphones	B-Application
at	O
the	O
same	O
place	O
,	O
and	O
typically	O
placed	O
at	O
90°	O
or	O
more	O
to	O
each	O
other	O
.	O
</s>
<s>
A	O
stereo	O
effect	O
is	O
achieved	O
through	O
differences	O
in	O
sound	O
pressure	O
level	O
between	O
two	O
microphones	B-Application
.	O
</s>
<s>
When	O
the	O
microphones	B-Application
are	O
bidirectional	O
and	O
placed	O
facing	O
±45°	O
with	O
respect	O
to	O
the	O
sound	O
source	O
,	O
the	O
X-Y-setup	O
is	O
called	O
a	O
Blumlein	O
Pair	O
.	O
</s>
<s>
This	O
technique	O
uses	O
two	O
parallel	O
microphones	B-Application
,	O
typically	O
omnidirectional	O
,	O
some	O
distance	O
apart	O
,	O
capturing	O
time-of-arrival	O
stereo	O
information	O
as	O
well	O
as	O
some	O
level	O
(	O
amplitude	O
)	O
difference	O
information	O
,	O
especially	O
if	O
employed	O
close	O
to	O
the	O
sound	O
source(s )	O
.	O
</s>
<s>
At	O
a	O
distance	O
of	O
about	O
50cm	O
(	O
0.5m	O
)	O
the	O
time	O
delay	O
for	O
a	O
signal	O
reaching	O
first	O
one	O
and	O
then	O
the	O
other	O
microphone	B-Application
from	O
the	O
side	O
is	O
approximately	O
1.5ms	O
(	O
1	O
to	O
2ms	O
)	O
.	O
</s>
<s>
If	O
the	O
distance	O
is	O
increased	O
between	O
the	O
microphones	B-Application
it	O
effectively	O
decreases	O
the	O
pickup	O
angle	O
.	O
</s>
<s>
Mid/side	O
coincident	O
technique	O
employs	O
a	O
bidirectional	O
microphone	B-Application
(	O
with	O
a	O
Figure	O
of	O
8	O
polar	O
pattern	O
)	O
facing	O
sideways	O
and	O
a	O
cardioid	O
(	O
generally	O
a	O
variety	O
of	O
cardioid	O
,	O
although	O
Alan	O
Blumlein	O
described	O
the	O
usage	O
of	O
an	O
omnidirectional	O
transducer	O
in	O
his	O
original	O
patent	O
)	O
facing	O
the	O
sound	O
source	O
.	O
</s>
<s>
The	O
Jecklin	B-Algorithm
Disk	I-Algorithm
technique	O
is	O
similar	O
to	O
A/B	O
recording	O
,	O
with	O
2	O
omni-directional	O
microphones	B-Application
at	O
36cm	O
apart	O
from	O
each	O
other	O
.	O
</s>
<s>
A	O
sound	O
absorbing	O
Jecklin	B-Algorithm
disk	I-Algorithm
of	O
35cm	O
is	O
placed	O
in	O
the	O
middle	O
between	O
the	O
two	O
microphones	B-Application
.	O
</s>
<s>
Jecklin	B-Algorithm
disk	I-Algorithm
has	O
a	O
relatively	O
small	O
distance	O
between	O
the	O
mics	O
.	O
</s>
<s>
Frequencies	O
coming	O
in	O
sideways	O
can	O
reach	O
only	O
one	O
microphone	B-Application
and	O
will	O
not	O
interfere	O
.	O
</s>
<s>
Therefore	O
,	O
Jecklin	B-Algorithm
disk	I-Algorithm
works	O
reasonably	O
well	O
when	O
converted	O
to	O
mono	O
.	O
</s>
<s>
Jecklin	B-Algorithm
disk	I-Algorithm
also	O
gives	O
phase	O
shifts	O
and	O
amplitude	O
differences	O
matching	O
well	O
with	O
what	O
a	O
real	O
pair	O
of	O
ears	O
would	O
hear	O
at	O
this	O
position	O
and	O
therefore	O
is	O
well	O
suited	O
for	O
headphone	O
playback	O
.	O
</s>
<s>
In	O
the	O
X-Y	O
techniques	O
,	O
the	O
microphones	B-Application
would	O
ideally	O
be	O
in	O
exactly	O
the	O
same	O
place	O
,	O
which	O
is	O
not	O
possible	O
–	O
if	O
they	O
are	O
slightly	O
separated	O
left	O
to	O
right	O
,	O
there	O
may	O
be	O
some	O
loss	O
of	O
high	O
frequencies	O
when	O
played	O
back	O
in	O
mono	O
,	O
so	O
they	O
are	O
often	O
separated	O
vertically	O
.	O
</s>
<s>
This	O
only	O
causes	O
problems	O
with	O
sound	O
from	O
above	O
or	O
below	O
the	O
height	O
of	O
the	O
microphones	B-Application
.	O
</s>
<s>
A-B	O
techniques	O
generally	O
use	O
two	O
separate	O
microphone	B-Application
units	O
,	O
often	O
mounted	O
on	O
a	O
bar	O
to	O
define	O
the	O
separation	O
.	O
</s>
<s>
X-Y	O
microphone	B-Application
capsules	O
can	O
be	O
mounted	O
in	O
one	O
unit	O
,	O
or	O
even	O
on	O
the	O
top	O
of	O
a	O
handheld	O
digital	O
recorder	O
.	O
</s>
<s>
They	O
are	O
often	O
used	O
in	O
small	O
'	O
pencil	O
microphones	B-Application
 '	O
to	O
mount	O
on	O
video	O
cameras	O
,	O
sometimes	O
even	O
coupled	O
to	O
the	O
zoom	O
.	O
</s>
