<s>
The	O
Sennheiser	B-Algorithm
MD	I-Algorithm
421	I-Algorithm
is	O
a	O
German	O
cardioid	O
dynamic	O
microphone	B-Application
,	O
widely	O
used	O
for	O
speech	O
in	O
broadcasting	O
and	O
for	O
music	O
in	O
live	O
concerts	O
and	O
the	O
recording	O
studio	O
.	O
</s>
<s>
Introduced	O
in	O
1960	O
,	O
the	O
internal	O
large-diaphragm	O
transducer	B-Algorithm
element	O
of	O
the	O
MD421	B-Algorithm
is	O
still	O
produced	O
unchanged	O
by	O
Sennheiser	O
.	O
</s>
<s>
The	O
MD421	B-Algorithm
is	O
considered	O
a	O
classic	O
,	O
an	O
industry	O
standard	O
.	O
</s>
<s>
With	O
a	O
diaphragm	O
diameter	O
of	O
,	O
the	O
MD421	B-Algorithm
is	O
classified	O
as	O
a	O
large-diaphragm	O
microphone	B-Application
.	O
</s>
<s>
Its	O
wide	O
frequency	O
response	O
(	O
30	O
–	O
17,000	O
Hz	O
±	O
3dB	O
)	O
exceeded	O
the	O
former	O
Hi-Fi	O
standard	O
and	O
came	O
close	O
to	O
the	O
performance	O
of	O
condenser	O
microphones	B-Application
.	O
</s>
<s>
The	O
compact	O
design	O
of	O
the	O
MD421	B-Algorithm
transducer	B-Algorithm
system	O
was	O
novel	O
at	O
the	O
time	O
,	O
because	O
directional	O
pickup	O
patterns	O
had	O
only	O
been	O
achieved	O
by	O
adding	O
sound	O
entry	O
ports	O
to	O
the	O
rear	O
of	O
the	O
element	O
(	O
for	O
instance	O
,	O
the	O
Electro-Voice	O
"	O
variable-D	O
system	O
"	O
with	O
a	O
row	O
of	O
ports	O
in	O
the	O
handle	O
.	O
)	O
</s>
<s>
Microphones	B-Application
with	O
sound-shaping	O
ports	O
could	O
only	O
be	O
held	O
in	O
the	O
hand	O
to	O
a	O
limited	O
extent	O
without	O
the	O
directional	O
effect	O
deteriorating	O
.	O
</s>
<s>
The	O
MD421	B-Algorithm
offered	O
a	O
smooth	O
,	O
closed	O
plastic	O
housing	O
without	O
ports	O
,	O
retaining	O
its	O
directional	O
pickup	O
pattern	O
no	O
matter	O
how	O
it	O
was	O
held	O
.	O
</s>
<s>
Another	O
special	O
technical	O
feature	O
of	O
the	O
MD421	B-Algorithm
is	O
the	O
hum	O
compensation	O
coil	O
:	O
It	O
is	O
wired	O
in	O
opposite	O
polarity	O
to	O
the	O
coil	O
of	O
the	O
converter	O
system	O
.	O
</s>
<s>
All	O
MD	O
421s	O
with	O
European	O
Kleintuchel	O
or	O
American	O
XLR	B-Device
connectors	I-Device
have	O
a	O
knurled	O
plastic	O
ring	O
between	O
the	O
housing	O
and	O
the	O
connector	O
,	O
with	O
which	O
an	O
adjustable	O
inductive	O
high-pass	O
filter	O
(	O
roll-off	O
filter	O
)	O
can	O
be	O
operated	O
.	O
</s>
<s>
The	O
"	O
S	O
"	O
(	O
speech	O
)	O
position	O
attenuates	O
the	O
transmission	O
of	O
low	O
frequencies	O
,	O
and	O
the	O
"	O
M	O
"	O
(	O
music	O
)	O
position	O
allows	O
the	O
microphone	B-Application
's	O
full	O
response	O
.	O
</s>
<s>
The	O
"	O
MD	O
"	O
stood	O
for	O
mikrofon	O
dynamische	O
(	O
dynamic	O
microphone	B-Application
)	O
.	O
</s>
<s>
At	O
the	O
end	O
of	O
the	O
1950s	O
,	O
Fritz	O
Sennheiser	O
directed	O
engineers	O
Paul-Friedrich	O
Warning	O
and	O
Johann-Friedrich	O
Fischer	O
to	O
develop	O
a	O
new	O
microphone	B-Application
.	O
</s>
<s>
In	O
1960	O
,	O
the	O
MD421	B-Algorithm
was	O
introduced	O
with	O
a	O
directional	O
pickup	O
pattern	O
,	O
advertised	O
by	O
the	O
manufacturer	O
as	O
a	O
studio	O
microphone	B-Application
.	O
</s>
<s>
The	O
light-colored	O
body	O
of	O
the	O
MD421	B-Algorithm
was	O
made	O
out	O
of	O
a	O
DuPont	O
polyoxymethylene	O
compound	O
sold	O
as	O
Delrin	O
.	O
</s>
<s>
Later	O
versions	O
of	O
the	O
MD421	B-Algorithm
were	O
molded	O
in	O
black	O
composite	O
.	O
</s>
<s>
Since	O
its	O
introduction	O
in	O
1960	O
,	O
the	O
MD421	B-Algorithm
has	O
established	O
itself	O
in	O
almost	O
all	O
areas	O
of	O
professional	O
sound	O
technology	O
,	O
especially	O
radio	O
and	O
television	O
transmission	O
technology	O
as	O
well	O
as	O
public	O
address	O
technology	O
(	O
PA	O
)	O
.	O
</s>
<s>
In	O
addition	O
to	O
its	O
sonic	O
advantages	O
,	O
the	O
microphone	B-Application
also	O
achieved	O
success	O
thanks	O
to	O
the	O
"	O
music	O
/	O
speech	O
filter	O
"	O
mentioned	O
above	O
.	O
</s>
<s>
This	O
high-pass	O
filter	O
has	O
proven	O
itself	O
both	O
when	O
used	O
as	O
a	O
vocal	O
microphone	B-Application
(	O
suppression	O
of	O
the	O
proximity	O
effect	O
and	O
plosives	O
)	O
and	O
when	O
broadcasting	O
and	O
recording	O
outside	O
to	O
reduce	O
wind	O
noise	O
.	O
</s>
<s>
The	O
characteristic	O
shape	O
of	O
the	O
MD421	B-Algorithm
was	O
part	O
of	O
the	O
appearance	O
of	O
countless	O
press	O
conferences	O
,	O
political	O
speeches	O
and	O
television	O
reports	O
well	O
into	O
the	O
1990s	O
.	O
</s>
<s>
In	O
1971	O
,	O
Sennheiser	O
introduced	O
another	O
dynamic	O
microphone	B-Application
but	O
with	O
a	O
very	O
long	O
metal	O
grille	O
:	O
the	O
Sennheiser	O
MD441	O
,	O
which	O
became	O
another	O
classic	O
.	O
</s>
<s>
The	O
microphone	B-Application
is	O
popular	O
with	O
recording	O
engineers	O
,	O
used	O
in	O
the	O
production	O
of	O
all	O
genres	O
of	O
music	O
.	O
</s>
<s>
The	O
MD421	B-Algorithm
is	O
primarily	O
used	O
for	O
drums	O
,	O
guitar	O
amplifiers	O
,	O
woodwinds	O
,	O
brass	O
and	O
percussion	O
instruments	O
.	O
</s>
<s>
Above	O
that	O
,	O
the	O
microphone	B-Application
exhibits	O
a	O
smooth	O
increase	O
in	O
upper	O
mid-range	O
frequencies	O
important	O
for	O
intelligibility	O
.	O
</s>
<s>
In	O
1966	O
,	O
Udo	O
Jürgens	O
won	O
the	O
Eurovision	O
Song	O
Contest	O
,	O
singing	O
the	O
song	O
"	O
Merci	O
,	O
Chérie	O
"	O
into	O
an	O
MD421	B-Algorithm
.	O
</s>
<s>
By	O
1971	O
,	O
the	O
contest	O
was	O
almost	O
entirely	O
performed	O
on	O
MD421	B-Algorithm
microphones	B-Application
.	O
</s>
<s>
The	O
Concert	O
for	O
Bangladesh	O
by	O
George	O
Harrison	O
included	O
many	O
MD421s	B-Algorithm
.	O
</s>
<s>
As	O
a	O
large-element	O
dynamic	O
microphone	B-Application
,	O
it	O
has	O
slower	O
impulse	O
response	O
and	O
less	O
resolution	O
in	O
higher	O
frequencies	O
compared	O
to	O
condenser	O
microphones	B-Application
,	O
and	O
is	O
therefore	O
less	O
suitable	O
as	O
the	O
main	O
microphone	B-Application
to	O
record	O
an	O
orchestra	O
,	O
or	O
as	O
the	O
overhead	O
microphone	B-Application
for	O
a	O
drum	O
kit	O
,	O
to	O
capture	O
the	O
fast	O
transients	O
of	O
cymbals	O
.	O
</s>
<s>
But	O
it	O
excels	O
at	O
its	O
intended	O
job	O
:	O
Jazz	O
guitarist	O
Brian	O
Tarquin	O
referred	O
to	O
the	O
ubiquitous	O
American	O
Shure	B-Algorithm
SM57	I-Algorithm
when	O
he	O
described	O
the	O
MD421	B-Algorithm
as	O
"	O
an	O
SM57	B-Algorithm
on	O
steroids	O
...	O
probably	O
one	O
of	O
the	O
most	O
diverse	O
mics	O
ever	O
made.	O
"	O
</s>
<s>
The	O
available	O
accessories	O
for	O
the	O
MD	O
421	O
include	O
a	O
short	O
microphone	B-Algorithm
stand	I-Algorithm
to	O
be	O
used	O
atop	O
tables	O
(	O
model	O
name	O
MZT	O
)	O
and	O
a	O
windscreen	O
(	O
MZW	O
)	O
to	O
cut	O
wind	O
noise	O
;	O
early	O
windscreens	O
were	O
made	O
of	O
nylon	O
and	O
later	O
ones	O
of	O
polyurethane	O
foam	O
.	O
</s>
<s>
A	O
shock-mount	O
microphone	B-Application
clip	O
(	O
MZS	O
)	O
provides	O
greater	O
isolation	O
for	O
heavy	O
vibrations	O
that	O
might	O
be	O
carried	O
through	O
the	O
microphone	B-Application
body	O
.	O
</s>
<s>
The	O
standard-issue	O
microphone	B-Application
clip	O
(	O
MZA	O
)	O
is	O
a	O
quick-change	O
device	O
that	O
latches	O
into	O
a	O
groove	O
on	O
the	O
housing	O
to	O
hold	O
the	O
microphone	B-Application
upright	O
.	O
</s>
<s>
(	O
Due	O
to	O
its	O
unusual	O
shape	O
,	O
the	O
MD421	B-Algorithm
cannot	O
be	O
used	O
with	O
commonly	O
available	O
microphone	B-Application
clips	O
.	O
)	O
</s>
<s>
The	O
supplied	O
microphone	B-Application
clip	O
is	O
pushed	O
into	O
a	O
groove	O
on	O
the	O
underside	O
of	O
the	O
microphone	B-Application
and	O
mechanically	O
locked	O
with	O
a	O
quick-release	O
button	O
.	O
</s>
<s>
Many	O
users	O
have	O
complained	O
about	O
the	O
tendency	O
of	O
the	O
supplied	O
microphone	B-Application
clip	O
to	O
let	O
go	O
of	O
the	O
microphone	B-Application
,	O
allowing	O
it	O
to	O
drop	O
,	O
especially	O
when	O
adjusted	O
quickly	O
for	O
instrumental	O
solos	O
,	O
or	O
when	O
mounted	O
pointing	O
downward	O
at	O
tom-tom	O
drums	O
.	O
</s>
<s>
Others	O
have	O
fabricated	O
a	O
larger	O
plastic	O
clip	O
that	O
works	O
more	O
like	O
a	O
standard	O
microphone	B-Application
clip	O
.	O
</s>
<s>
The	O
microphone	B-Application
was	O
produced	O
in	O
the	O
following	O
versions	O
:	O
</s>
<s>
MD	O
421	O
de	O
Luxe	O
with	O
black	O
housing	O
,	O
gold-colored	O
grille	O
,	O
same	O
internally	O
as	O
the	O
MD421-N	O
.	O
</s>
<s>
MD	O
421-U	O
has	O
a	O
black	O
housing	O
and	O
balanced	O
XLR	B-Device
connector	I-Device
.	O
</s>
<s>
The	O
421	O
U4	O
and	O
U5	O
versions	O
differ	O
in	O
the	O
thread	O
on	O
the	O
removable	O
microphone	B-Application
clip	O
.	O
</s>
