<s>
A	O
parabolic	B-Architecture
loudspeaker	I-Architecture
is	O
a	O
loudspeaker	O
which	O
seeks	O
to	O
focus	O
its	O
sound	O
in	O
coherent	O
plane	O
waves	O
either	O
by	O
reflecting	O
sound	O
output	O
from	O
a	O
speaker	B-Device
driver	I-Device
to	O
a	O
parabolic	O
reflector	O
aimed	O
at	O
the	O
target	O
audience	O
,	O
or	O
by	O
arraying	O
drivers	O
on	O
a	O
parabolic	O
surface	O
.	O
</s>
<s>
The	O
resulting	O
beam	O
of	O
sound	O
travels	O
farther	O
,	O
with	O
less	O
dissipation	O
in	O
air	O
,	O
than	O
horn	B-Device
loudspeakers	I-Device
,	O
and	O
can	O
be	O
more	O
focused	O
than	O
line	B-Architecture
array	I-Architecture
loudspeakers	O
allowing	O
sound	O
to	O
be	O
sent	O
to	O
isolated	O
audience	O
targets	O
.	O
</s>
<s>
The	O
parabolic	B-Architecture
loudspeaker	I-Architecture
has	O
been	O
used	O
for	O
such	O
diverse	O
purposes	O
as	O
directing	O
sound	O
at	O
faraway	O
targets	O
in	O
performing	O
arts	O
centers	O
and	O
stadia	B-Application
,	O
for	O
industrial	O
testing	O
,	O
for	O
intimate	O
listening	O
at	O
museum	O
exhibits	O
,	O
and	O
as	O
a	O
sonic	O
weapon	O
.	O
</s>
<s>
A	O
parabolic	B-Architecture
loudspeaker	I-Architecture
can	O
send	O
sound	O
farther	O
than	O
traditional	O
loudspeaker	O
designs	O
.	O
</s>
<s>
The	O
focused	O
waves	O
of	O
a	O
parabolic	B-Architecture
loudspeaker	I-Architecture
tend	O
to	O
dissipate	O
in	O
air	O
at	O
about	O
3dB	O
SPL	O
per	O
doubling	O
of	O
distance	O
,	O
rather	O
than	O
the	O
usual	O
6dB	O
of	O
conventional	O
loudspeakers	O
.	O
</s>
<s>
In	O
a	O
parabolic	O
reflecting	O
loudspeaker	O
,	O
one	O
or	O
more	O
speaker	B-Device
drivers	I-Device
are	O
mounted	O
at	O
the	O
focal	O
point	O
of	O
a	O
parabola	O
,	O
pointing	O
away	O
from	O
the	O
audience	O
,	O
toward	O
the	O
parabolic	O
surface	O
.	O
</s>
<s>
In	O
addition	O
,	O
some	O
frequencies	O
are	O
reflected	O
more	O
efficiently	O
than	O
others	O
,	O
so	O
the	O
frequency	O
response	O
is	O
uneven	O
unless	O
audio	B-Algorithm
signal	I-Algorithm
processing	I-Algorithm
correction	O
is	O
applied	O
before	O
the	O
signal	O
reaches	O
the	O
amplifier	O
.	O
</s>
<s>
The	O
presence	O
and	O
placement	O
of	O
the	O
speaker	B-Device
driver	I-Device
prevents	O
the	O
center	O
of	O
the	O
parabolic	O
dish	O
from	O
reflecting	O
sound	O
outward	O
,	O
as	O
that	O
sound	O
would	O
reflect	O
back	O
into	O
the	O
speaker	B-Device
driver	I-Device
itself	O
.	O
</s>
<s>
In	O
some	O
loudspeaker	O
designs	O
,	O
a	O
hole	O
is	O
cut	O
at	O
the	O
center	O
of	O
the	O
parabolic	O
dish	O
,	O
or	O
damping	O
material	O
placed	O
,	O
such	O
that	O
no	O
sound	O
is	O
reflected	O
directly	O
at	O
the	O
speaker	B-Device
driver	I-Device
.	O
</s>
<s>
A	O
loudspeaker	O
can	O
be	O
constructed	O
with	O
multiple	O
speaker	B-Device
drivers	I-Device
arrayed	O
on	O
the	O
surface	O
of	O
a	O
parabolic	O
dish	O
.	O
</s>
<s>
The	O
expense	O
of	O
a	O
multiple	O
driver	O
loudspeaker	O
is	O
typically	O
higher	O
than	O
a	O
reflector-type	O
parabolic	O
dish	O
due	O
to	O
the	O
increased	O
number	O
of	O
speaker	B-Device
driver	I-Device
components	O
and	O
amplifier	O
channels	O
.	O
</s>
<s>
Modern	O
sonic	O
weapons	O
such	O
the	O
Long	O
Range	O
Acoustic	O
Device	O
(	O
LRAD	O
)	O
rely	O
on	O
multiple	O
loudspeaker	B-Device
drivers	I-Device
for	O
increased	O
sound	O
power	O
,	O
and	O
may	O
array	O
them	O
in	O
a	O
flat	O
plane	O
rather	O
than	O
on	O
a	O
parabolic	O
surface	O
.	O
</s>
<s>
Since	O
1986	O
,	O
parabolic	B-Architecture
loudspeakers	I-Architecture
have	O
been	O
designed	O
to	O
give	O
museum	O
exhibits	O
a	O
very	O
focused	O
sound	O
field	O
so	O
that	O
each	O
exhibit	O
can	O
send	O
sound	O
to	O
just	O
one	O
or	O
two	O
museum-goers	O
without	O
having	O
too	O
much	O
interference	O
and	O
an	O
increase	O
in	O
background	O
noise	O
.	O
</s>
<s>
In	O
2002	O
,	O
Meyer	O
Sound	O
produced	O
the	O
SB-2	O
,	O
a	O
bi-amplified	O
loudspeaker	O
which	O
uses	O
a	O
parabolic	O
dish	O
as	O
the	O
front	O
face	O
of	O
the	O
enclosure	B-Device
.	O
</s>
<s>
Slightly	O
smaller	O
than	O
the	O
SB-1	O
,	O
the	O
SB-2	O
uses	O
28	O
drivers	O
arrayed	O
on	O
the	O
surface	O
of	O
the	O
parabola	O
combined	O
with	O
a	O
coaxial	O
horn	O
with	O
a	O
throat	O
and	O
a	O
voice	B-Device
coil	I-Device
.	O
</s>
<s>
A	O
parabolic	B-Architecture
loudspeaker	I-Architecture
can	O
be	O
used	O
to	O
test	O
the	O
sound-damping	O
characteristics	O
of	O
materials	O
used	O
for	O
soundproofing	O
.	O
</s>
<s>
A	O
parabolic	B-Architecture
loudspeaker	I-Architecture
is	O
aimed	O
at	O
the	O
material	O
under	O
test	O
,	O
and	O
a	O
parabolic	O
microphone	O
is	O
used	O
to	O
pick	O
up	O
the	O
sound	O
detected	O
on	O
the	O
other	O
side	O
of	O
the	O
material	O
.	O
</s>
<s>
The	O
narrow	O
directionality	O
of	O
the	O
parabolic	B-Architecture
loudspeaker	I-Architecture
and	O
microphone	O
aid	O
in	O
reducing	O
the	O
amount	O
of	O
stray	O
sound	O
that	O
could	O
skew	O
test	O
results	O
.	O
</s>
