<s>
A	O
line	B-Architecture
array	I-Architecture
is	O
a	O
loudspeaker	O
system	O
that	O
is	O
made	O
up	O
of	O
a	O
number	O
of	O
usually	O
identical	O
loudspeaker	O
elements	O
mounted	O
in	O
a	O
line	O
and	O
fed	O
in	O
phase	O
,	O
to	O
create	O
a	O
near-line	O
source	O
of	O
sound	O
.	O
</s>
<s>
The	O
distance	O
between	O
adjacent	O
drivers	O
is	O
close	O
enough	O
that	O
they	O
constructively	O
interfere	O
with	O
each	O
other	O
to	O
send	O
sound	O
waves	O
farther	O
than	O
traditional	O
horn-loaded	B-Device
loudspeakers	I-Device
,	O
and	O
with	O
a	O
more	O
evenly	O
distributed	O
sound	O
output	O
pattern	O
.	O
</s>
<s>
Line	B-Architecture
arrays	I-Architecture
can	O
be	O
oriented	O
in	O
any	O
direction	O
,	O
but	O
their	O
primary	O
use	O
in	O
public	O
address	O
is	O
in	O
vertical	O
arrays	O
which	O
provide	O
a	O
very	O
narrow	O
vertical	O
output	O
pattern	O
useful	O
for	O
focusing	O
sound	O
at	O
audiences	O
without	O
wasting	O
output	O
energy	O
on	O
ceilings	O
or	O
empty	O
air	O
above	O
the	O
audience	O
.	O
</s>
<s>
A	O
vertical	O
line	B-Architecture
array	I-Architecture
displays	O
a	O
normally	O
wide	O
horizontal	O
pattern	O
useful	O
for	O
supplying	O
sound	O
to	O
the	O
majority	O
of	O
a	O
concert	O
audience	O
.	O
</s>
<s>
Horizontal	O
line	B-Architecture
arrays	I-Architecture
,	O
by	O
contrast	O
,	O
have	O
a	O
very	O
narrow	O
horizontal	O
output	O
pattern	O
and	O
a	O
tall	O
vertical	O
pattern	O
.	O
</s>
<s>
A	O
row	O
of	O
subwoofers	B-Application
along	O
the	O
front	O
edge	O
of	O
a	O
concert	O
stage	O
can	O
behave	O
as	O
a	O
horizontal	O
line	B-Architecture
array	I-Architecture
unless	O
the	O
signal	O
supplied	O
to	O
them	O
is	O
adjusted	O
(	O
delayed	O
,	O
polarized	O
,	O
equalized	O
)	O
to	O
shape	O
the	O
pattern	O
otherwise	O
.	O
</s>
<s>
Modern	O
line	B-Architecture
arrays	I-Architecture
use	O
separate	O
drivers	O
for	O
high-	O
,	O
mid	O
-	O
and	O
low-frequency	O
passbands	B-Algorithm
.	O
</s>
<s>
For	O
the	O
line	O
source	O
to	O
work	O
,	O
the	O
drivers	O
in	O
each	O
passband	B-Algorithm
need	O
to	O
be	O
in	O
a	O
line	O
.	O
</s>
<s>
Therefore	O
,	O
each	O
enclosure	O
must	O
be	O
designed	O
to	O
rig	O
together	O
closely	O
to	O
form	O
columns	O
composed	O
of	O
high-	O
,	O
mid	O
-	O
and	O
low-frequency	O
speaker	B-Device
drivers	I-Device
.	O
</s>
<s>
The	O
large	O
format	O
line	B-Architecture
array	I-Architecture
has	O
become	O
the	O
standard	O
for	O
large	O
concert	O
venues	O
and	O
outdoor	O
festivals	O
,	O
where	O
such	O
systems	O
can	O
be	O
flown	O
(	O
rigged	O
,	O
suspended	O
)	O
from	O
a	O
structural	O
beam	O
,	O
ground	O
support	O
tower	O
or	O
off	O
a	O
tall	O
A-frame	O
truss	O
tower	O
.	O
</s>
<s>
The	O
lower	O
portion	O
of	O
the	O
line	B-Architecture
array	I-Architecture
is	O
generally	O
curved	O
backwards	O
to	O
increase	O
dispersion	O
at	O
the	O
bottom	O
of	O
the	O
array	O
and	O
allow	O
sound	O
to	O
reach	O
more	O
audience	O
members	O
.	O
</s>
<s>
Typically	O
,	O
cabinets	O
used	O
in	O
line	B-Architecture
arrays	I-Architecture
are	O
trapezoidal	O
,	O
connected	O
by	O
specialized	O
rigging	O
hardware	O
.	O
</s>
<s>
The	O
line	B-Architecture
array	I-Architecture
effect	O
of	O
the	O
narrowing	O
of	O
the	O
beam	O
with	O
increasing	O
frequency	O
was	O
first	O
demonstrated	O
by	O
acoustical	O
pioneer	O
Harry	O
Olson	O
.	O
</s>
<s>
Olson	O
used	O
line	B-Architecture
array	I-Architecture
concepts	O
to	O
develop	O
the	O
column	O
speaker	O
in	O
which	O
vertically	O
aligned	O
drivers	O
in	O
a	O
single	O
enclosure	O
produced	O
mid-range	O
output	O
in	O
a	O
wide	O
horizontal	O
and	O
narrow	O
vertical	O
pattern	O
.	O
</s>
<s>
Line	B-Architecture
arrays	I-Architecture
have	O
been	O
around	O
for	O
over	O
half	O
a	O
century	O
but	O
until	O
recently	O
most	O
were	O
voice	O
range	O
only	O
.	O
</s>
<s>
A	O
multi-band	O
line	B-Architecture
array	I-Architecture
elements	O
in	O
a	O
horizontally	O
oriented	O
enclosure	O
was	O
suggested	O
by	O
Joseph	O
D'Appolito	O
in	O
1983	O
.	O
</s>
<s>
However	O
,	O
it	O
was	O
L-Acoustics	O
'	O
V-DOSC	O
line	B-Architecture
array	I-Architecture
in	O
the	O
mid-1990s	O
that	O
would	O
show	O
the	O
concert	O
world	O
that	O
a	O
more	O
level	O
and	O
smoother	O
frequency	O
response	O
can	O
come	O
from	O
fewer	O
boxes	O
in	O
a	O
line	B-Architecture
array	I-Architecture
.	O
</s>
<s>
Pure	O
line	B-Architecture
array	I-Architecture
theory	O
is	O
based	O
on	O
pure	O
geometry	O
and	O
the	O
thought	O
experiment	O
of	O
the	O
"	O
free	O
field	O
"	O
where	O
sound	O
is	O
free	O
to	O
propagate	O
free	O
of	O
environmental	O
factors	O
such	O
as	O
room	O
reflections	O
or	O
temperature	O
refraction	O
.	O
</s>
<s>
Interference	O
pattern	O
is	O
the	O
term	O
applied	O
to	O
the	O
dispersion	O
pattern	O
of	O
a	O
line	B-Architecture
array	I-Architecture
.	O
</s>
<s>
At	O
frequencies	O
below	O
100Hz	O
(	O
wavelength	O
of	O
11.3ft	O
)	O
the	O
line	B-Architecture
array	I-Architecture
which	O
is	O
less	O
than	O
approximately	O
3	O
meter	O
long	O
will	O
start	O
to	O
become	O
omnidirectional	O
,	O
so	O
the	O
system	O
will	O
not	O
conform	O
to	O
line	B-Architecture
array	I-Architecture
theory	O
across	O
all	O
frequencies	O
.	O
</s>
<s>
Above	O
about	O
400Hz	O
the	O
driver	O
cones	O
themselves	O
become	O
directional	O
,	O
again	O
violating	O
the	O
theory	O
’s	O
assumptions	O
,	O
and	O
at	O
high	O
frequencies	O
,	O
many	O
practical	O
systems	O
use	O
directional	O
waveguides	O
whose	O
behavior	O
cannot	O
be	O
described	O
using	O
classical	O
line	B-Architecture
array	I-Architecture
theory	O
.	O
</s>
<s>
In	O
short	O
,	O
the	O
geometry	O
of	O
real-world	O
audio	O
line	B-Architecture
arrays	I-Architecture
as	O
used	O
in	O
public	O
address	O
systems	O
can	O
only	O
be	O
modeled	O
approximately	O
by	O
line	B-Architecture
array	I-Architecture
theory	O
,	O
and	O
only	O
in	O
the	O
100	O
–	O
400Hz	O
range	O
.	O
</s>
<s>
Practical	O
line	B-Architecture
array	I-Architecture
systems	O
act	O
as	O
line	O
sources	O
only	O
in	O
the	O
low	O
-	O
and	O
mid	O
-	O
frequencies	O
.	O
</s>
<s>
In	O
a	O
properly	O
designed	O
line	B-Architecture
array	I-Architecture
system	O
,	O
that	O
pattern	O
should	O
closely	O
match	O
the	O
low-frequency	O
directional	O
characteristic	O
of	O
the	O
array	O
.	O
</s>
<s>
If	O
this	O
is	O
achieved	O
,	O
then	O
the	O
wave	O
guide	O
elements	O
can	O
be	O
integrated	O
into	O
the	O
line	B-Architecture
array	I-Architecture
and	O
,	O
with	O
proper	O
equalization	O
and	O
crossovers	O
,	O
the	O
beam	O
from	O
the	O
high	O
frequencies	O
and	O
the	O
constructive	O
interference	O
of	O
the	O
low	O
frequencies	O
can	O
be	O
made	O
to	O
align	O
so	O
that	O
the	O
resulting	O
arrayed	O
system	O
provides	O
consistent	O
coverage	O
.	O
</s>
<s>
Also	O
,	O
the	O
problem	O
with	O
straight	O
line	B-Architecture
arrays	I-Architecture
is	O
that	O
the	O
beam	O
is	O
far	O
too	O
narrow	O
at	O
high	O
frequencies	O
.	O
</s>
<s>
Large-format	O
line	B-Architecture
arrays	I-Architecture
are	O
designed	O
for	O
large	O
venues	O
or	O
outdoor	O
festivals	O
.	O
</s>
<s>
Mid-format	O
line	B-Architecture
arrays	I-Architecture
are	O
typically	O
two	O
or	O
three-way	O
and	O
use	O
10	O
or	O
12inch	O
low-frequency	O
drivers	O
.	O
</s>
<s>
Examples	O
include	O
L-Acoustics	O
SOUNDVISION	O
,	O
Adamson	O
Shooter	O
,	O
Electro-Voice	O
LAPS	O
(	O
Line	B-Architecture
Array	I-Architecture
Prediction	O
Software	O
)	O
,	O
D&B	O
Audiotechnik	O
ArrayCalc	O
,	O
and	O
JBL	O
Vertec	O
Line	B-Architecture
Array	I-Architecture
Calculator	O
.	O
</s>
<s>
It	O
is	O
similar	O
to	O
EASE	O
but	O
has	O
only	O
features	O
and	O
calculations	O
specific	O
to	O
Line	B-Architecture
arrays	I-Architecture
.	O
</s>
<s>
Other	O
line	B-Architecture
array	I-Architecture
brands	O
that	O
use	O
EaseFocus	O
include	O
Bose	O
Professional	O
,	O
Community	O
Professional	O
Loudspeakers	O
,	O
Electro-Voice	O
,	O
QSC	O
,	O
RCF	O
,	O
and	O
VUE	O
Audiotechnik	O
.	O
</s>
<s>
If	O
height	O
or	O
lack	O
of	O
rigging	O
points	O
does	O
not	O
permit	O
flying	O
the	O
speakers	O
,	O
the	O
speakers	O
are	O
typically	O
stacked	O
on	O
the	O
stage	O
or	O
on	O
subwoofers	B-Application
using	O
a	O
custom	O
stacking	O
frame	O
.	O
</s>
<s>
Stacking	O
of	O
line	B-Architecture
arrays	I-Architecture
is	O
common	O
in	O
smaller	O
venues	O
and	O
in	O
temporary	O
installations	O
.	O
</s>
