<s>
In	O
the	O
field	O
of	O
acoustics	O
,	O
a	O
diaphragm	B-Device
is	O
a	O
transducer	B-Algorithm
intended	O
to	O
inter-convert	O
mechanical	O
vibrations	O
to	O
sounds	O
,	O
or	O
vice	O
versa	O
.	O
</s>
<s>
The	O
varying	O
air	O
pressure	O
of	O
sound	O
waves	O
imparts	O
mechanical	O
vibrations	O
to	O
the	O
diaphragm	B-Device
which	O
can	O
then	O
be	O
converted	O
to	O
some	O
other	O
type	O
of	O
signal	O
;	O
examples	O
of	O
this	O
type	O
of	O
diaphragm	B-Device
are	O
found	O
in	O
microphones	B-Application
and	O
the	O
human	O
eardrum	O
.	O
</s>
<s>
Conversely	O
a	O
diaphragm	B-Device
vibrated	O
by	O
a	O
source	O
of	O
energy	O
beats	O
against	O
the	O
air	O
,	O
creating	O
sound	O
waves	O
.	O
</s>
<s>
Examples	O
of	O
this	O
type	O
of	O
diaphragm	B-Device
are	O
loudspeaker	B-Device
cones	I-Device
and	O
earphone	O
diaphragms	B-Device
and	O
are	O
found	O
in	O
air	O
horns	O
.	O
</s>
<s>
In	O
a	O
dynamic	O
loudspeaker	O
,	O
a	O
diaphragm	B-Device
is	O
the	O
thin	O
,	O
semi-rigid	O
membrane	O
attached	O
to	O
the	O
voice	B-Device
coil	I-Device
,	O
which	O
moves	O
in	O
a	O
magnetic	O
gap	O
,	O
vibrating	O
the	O
diaphragm	B-Device
,	O
and	O
producing	O
sound	O
.	O
</s>
<s>
It	O
can	O
also	O
be	O
called	O
a	O
cone	O
,	O
though	O
not	O
all	O
speaker	O
diaphragms	B-Device
are	O
cone-shaped	O
.	O
</s>
<s>
Diaphragms	B-Device
are	O
also	O
found	O
in	O
headphones	B-Device
.	O
</s>
<s>
Other	O
materials	O
used	O
for	O
diaphragms	B-Device
include	O
polypropylene	O
(	O
PP	O
)	O
,	O
polyetheretherketone	O
(	O
PEEK	O
)	O
polycarbonate	O
(	O
PC	O
)	O
,	O
Mylar	O
(	O
PET	O
)	O
,	O
silk	O
,	O
glassfibre	O
,	O
carbon	O
fibre	O
,	O
titanium	O
,	O
aluminium	O
,	O
aluminium-magnesium	O
alloy	O
,	O
nickel	O
,	O
and	O
beryllium	O
.	O
</s>
<s>
The	O
purpose	O
of	O
the	O
cone/surround	O
assembly	O
is	O
to	O
accurately	O
reproduce	O
the	O
voice	B-Device
coil	I-Device
signal	O
waveform	O
.	O
</s>
<s>
Inaccurate	O
reproduction	O
of	O
the	O
voice	B-Device
coil	I-Device
signal	O
results	O
in	O
acoustical	O
distortion	O
.	O
</s>
<s>
The	O
cone	O
stiffness/damping	O
plus	O
the	O
surround	O
's	O
linearity/damping	O
play	O
a	O
crucial	O
role	O
in	O
accuracy	O
of	O
the	O
reproduced	O
voice	B-Device
coil	I-Device
signal	O
waveform	O
.	O
</s>
<s>
Other	O
types	O
of	O
speakers	O
(	O
such	O
as	O
electrostatic	B-Device
loudspeakers	I-Device
)	O
may	O
use	O
a	O
thin	O
membrane	O
instead	O
of	O
a	O
cone	O
.	O
</s>
<s>
Microphones	B-Application
can	O
be	O
thought	O
of	O
as	O
speakers	O
in	O
reverse	O
.	O
</s>
<s>
The	O
sound	O
waves	O
strike	O
the	O
thin	O
diaphragm	B-Device
,	O
causing	O
it	O
to	O
vibrate	O
.	O
</s>
<s>
Microphone	B-Application
diaphragms	B-Device
,	O
unlike	O
speaker	O
diaphragms	B-Device
,	O
tend	O
to	O
be	O
thin	O
and	O
flexible	O
,	O
since	O
they	O
need	O
to	O
absorb	O
as	O
much	O
sound	O
as	O
possible	O
.	O
</s>
<s>
In	O
a	O
condenser	O
microphone	B-Application
,	O
the	O
diaphragm	B-Device
is	O
placed	O
in	O
front	O
of	O
a	O
plate	O
and	O
is	O
charged	O
.	O
</s>
<s>
In	O
a	O
dynamic	O
microphone	B-Application
,	O
the	O
diaphragm	B-Device
is	O
glued	O
to	O
a	O
magnetic	O
coil	O
,	O
similar	O
to	O
the	O
one	O
in	O
a	O
dynamic	O
loudspeaker	O
.	O
</s>
<s>
(	O
In	O
fact	O
,	O
a	O
dynamic	O
speaker	O
can	O
be	O
used	O
as	O
a	O
rudimentary	O
microphone	B-Application
,	O
and	O
vice	O
versa	O
.	O
)	O
</s>
<s>
The	O
diaphragm	B-Device
in	O
a	O
microphone	B-Application
works	O
similarly	O
to	O
the	O
human	O
eardrum	O
.	O
</s>
<s>
In	O
a	O
phonograph	O
reproducer	O
,	O
the	O
diaphragm	B-Device
is	O
a	O
flat	O
disk	O
of	O
typically	O
mica	O
or	O
isinglass	O
that	O
converts	O
the	O
mechanical	O
vibration	O
imparted	O
on	O
the	O
buttress	O
from	O
the	O
recorded	O
groove	O
into	O
sound	O
.	O
</s>
