<s>
DUPLEX	O
was	O
the	O
trade	O
name	O
given	O
by	O
Altec	O
Lansing	O
to	O
its	O
line	O
of	O
coaxial	B-Device
loudspeakers	I-Device
,	O
beginning	O
with	O
the	O
first	O
model	O
601	O
in	O
1943	O
.	O
</s>
<s>
There	O
has	O
been	O
much	O
confusion	O
about	O
the	O
original	O
601	O
due	O
to	O
the	O
fact	O
that	O
very	O
few	O
were	O
made	O
,	O
with	O
almost	O
no	O
survivors	O
,	O
and	O
because	O
the	O
model	O
name	O
was	O
re-used	O
in	O
the	O
1950s	O
for	O
a	O
completely	O
different	O
Altec	B-Device
Lansing	I-Device
Duplex	I-Device
driver	O
.	O
</s>
<s>
The	O
1950s	O
version	O
of	O
the	O
601	O
was	O
a	O
12	O
"	O
diameter	O
coaxial	B-Device
speaker	I-Device
with	O
a	O
miniature	O
HF	O
compression	O
driver	O
mounted	O
within	O
the	O
motor	O
of	O
the	O
LF	O
driver	O
using	O
permanent	O
magnets	O
.	O
</s>
