<s>
A	O
super	B-Device
tweeter	I-Device
is	O
a	O
speaker	B-Device
driver	I-Device
intended	O
to	O
produce	O
ultra	O
high	O
frequencies	O
in	O
a	O
multi-driver	O
loudspeaker	O
system	O
.	O
</s>
<s>
Super	B-Device
tweeters	I-Device
are	O
sometimes	O
found	O
in	O
high	O
fidelity	O
speaker	O
systems	O
and	O
sometimes	O
even	O
in	O
home	O
theater	O
systems	O
.	O
</s>
<s>
They	O
are	O
used	O
to	O
supplement	O
the	O
sound	O
of	O
tweeters	B-Device
by	O
reproducing	O
frequencies	O
which	O
the	O
tweeter	B-Device
may	O
produce	O
only	O
with	O
a	O
narrow	O
polar	O
output	O
,	O
or	O
perhaps	O
with	O
distortion	O
.	O
</s>
<s>
A	O
super	B-Device
tweeter	I-Device
is	O
generally	O
intended	O
to	O
respond	O
well	O
into	O
ultrasonic	B-Application
frequencies	O
over	O
20kHz	O
,	O
the	O
commonly	O
accepted	O
upper	O
frequency	O
limit	O
of	O
human	O
hearing	O
.	O
</s>
<s>
Super	B-Device
tweeters	I-Device
have	O
been	O
designed	O
for	O
psychoacoustic	O
testing	O
,	O
for	O
extended-range	O
digital	O
audio	O
such	O
as	O
Super	O
Audio	O
CD	O
intended	O
for	O
audiophiles	O
,	O
for	O
biologists	O
performing	O
research	O
on	O
animal	O
response	O
to	O
sounds	O
,	O
and	O
for	O
ambient	O
sound	O
systems	O
in	O
zoos	O
.	O
</s>
<s>
Ribbon	O
tweeters	B-Device
have	O
been	O
made	O
that	O
can	O
reproduce	O
80kHz	O
and	O
even	O
100kHz	O
.	O
</s>
