Reference Line
/ Line Array Technology
ISP Technologies has developed two new line
array products the Reference Line 210 and Reference Line
112. The Reference Line 210 is a 3-way Active System
including two 10 inch woofers, a large format, 4-inch
diaphragm mid frequency compression driver and dual 1.75
inch polyester diaphragm neodymium high frequency
drivers. The Reference Line 112 is a 3-way Active system
including a single 12 inch woofer, a large format,
4-inch diaphragm mid frequency and a 1.75 inch polyester
diaphragm neodymium high frequency driver. Both Line
Array Systems provide extremely wide horizontal
dispersion and stunning high fidelity performance. The
audio professionals that have heard the ISP Line Array
Systems claim they provide higher performance, better
pattern coverage and the highest fidelity ever heard. We
think so too! After thousands of hours of mathematical
simulation, the development of ISP’s proprietary Line
Sim software and rigorous engineering product design ISP
Technologies offer the ultimate in Line Array
technology. ISP also offers application specific, custom
Line Array system design. ISP will design a custom line
array specifically engineered for your specific room or
venue.
ISP Technologies, utilizing their proprietary LINESIM™
software program, has designed a custom line array
system for the 3000-seat Living Stones Church in Alvin
Texas. The Living Stone Church presented a formidable
challenge in the design of a high performance sound
system. The structure of the church is a round dome of
88-foot diameter, with a 100-foot distance from the
front podium to the sound booth at the rear of the dome.
It is obviously desirable to keep as much of the sound
energy off the dome as possible, yet achieve a
horizontal dispersion of 180 degrees.
ISP therefore, decided to custom design a 25,000 watt
Reference Line 210 Speaker system with multiple boxes in
a vertical line. Individual Line Array boxes have very
narrow dispersion in the vertical direction at high
frequencies, but wide vertical dispersion at low
frequencies. The narrow vertical dispersion at low
frequencies is achieved by a long line of boxes, with a
longer line having tighter dispersion at lower
frequencies. Once the wavelength of the sound becomes
longer than the line length, the dispersion broadens
out. Because of this tighter, more uniform vertical
dispersion, our line array provides superior performance
in the Living Stones Church. The boxes are over 5 feet
in height (5 boxes per side), and so will maintain
vertical dispersion control to below 200 Hz.
The subwoofers, which handle
frequencies below 100 Hz, are floor-mounted boxes, which
afford no vertical dispersion control. Most line
arrays built by other manufacturers use small cone
speakers up to about 1.5 KHz (or higher). These are
usually allowed to have wide vertical dispersion, so
that a particular seat hears the summation of many of
them (this is needed, since they are low efficiency
devices). But this is self-defeating, since the
curvature of the array and the shorter wavelengths at
these frequencies mean that the summation is not in
phase, which results in a severe response dip in this
region (the missing midrange). This is also combined
with the fact that cone speakers “break up” in this
frequency region, meaning the cone does not move like a
solid piston, but rather like a wet noodle, which
results in notches in the response and lack of clarity
in the sound. To get around this, the ISP Technologies
Reference Line 210 speaker uses a compression driver
with a 4-inch voice coil and 4-inch diaphragm in the
critical 700 Hz to 2.5 KHz region. Its diaphragm does
not break up in this frequency band. Also, it is coupled
to a horn with well-controlled vertical dispersion, so
that any person in the audience hears only one or two of
these devices, avoiding response dips due to phase
cancellations. The result is midrange response
smoothness and clarity that surpasses all other line
array in this price range.
The high frequency performance of the Living Stones
system is exceptional, due to the choice of drivers used
and the sophistication of the acoustic lens/horn
devices. These drivers use polyester diaphragms, as
opposed to titanium that “ring” and can produce an
annoying high end. Also, their 1.75 inch diaphragms and
1-inch throat sized are small enough to achieve extended
frequency response and wide horizontal dispersion. The
acoustic lenses focus this energy in a very tight
vertical pattern, so that multiple drivers do not
interact, which would result in peaks and notches in the
high frequency response. Finally, the horizontal
dispersion the Reference Line 210 speakers have, has
been carefully designed to be exceptionally wide (up to
120 degrees).
The Music Director at Living Stones wanted to achieve an
spl of 110db at 60 feet and the Custom Designed
Reference 210 Line Array System delivered. With headroom
to spare and ruler flat response, the Reference Line
Array delivered 115db spl at 60 feet. The most common
comment upon hearing the system was “WOW”. To find out
how to order a Custom Designed System, or any ISP
product, contact ISP Technologies at 248-673-7790.
Clarkston, MI
October 8, 2003
ISP “Hangs” with the Big Boys.
ISP Technologies, Inc. introduces a new line array
system: the Reference Line 210™. The Reference Line 210
is a high performance, mid-size, triamplified line array
element with exceptional fidelity. With a 12 degree
vertical by 120 degree horizontal dispersion the
Reference Line 210 may be used in groups or four or more
(in combination with subwoofers) in Theatres, Clubs, and
Churches from 500 seats and up. It achieves highly
uniform response throughout the listening area using a
careful blend of sophisticated design techniques.
Unlike nearly all other line array boxes that use two or
more low-efficiency cone midrange speakers up to 1.5 to
2.5 KHz, the Reference Line 210 uses a single
high-efficiency midrange compression driver with a
4-inch diaphragm. This avoids three problems that plague
the cone midrange approach. First, the side-by-side
mounting of the cones limits the horizontal dispersion.
This is avoided in our design by having a single
midrange device that radiates through a narrow vertical
slot, resulting in very wide, uniform horizontal
dispersion. Second, midrange cone drivers are very low
efficiency, and to overcome this, other line arrays are
designed with wide vertical dispersion in this band, so
that the output of many boxes sum together at these
frequencies. But if the array is highly curved, or very
long, the mid wavelengths are short enough that
destructive interference occurs, resulting in a midrange
suckout. This is avoided in the ISP design by using a
high-efficiency device and limiting the vertical
dispersion, so that only a few boxes are heard in this
band at any one seat. Third, midrange cone drivers
suffer from cone breakup, which causes dips in the
frequency response and a loss of clarity. The ISP
Reference Line includes a 4-inch diaphragm midrange
compression driver driven by a 4-inch voice coil, with
no breakup in the midrange band, resulting in stunning
clarity.
The high frequencies are handled by a pair of
exceptional quality compression drivers with 1.75 inch
polyester diaphragms and neodymium magnets. The
polyester diaphragms deliver sweet, clean highs and do
not suffer from the ringing which plague our competitors
titanium diaphragms. The compact size and extreme high
energy of the neo magnets allow the drivers to be packed
very closely, to generate extended HF response. The low
frequencies are handled by a pair of 10 inch woofers
with neodymium magnets for light weight and edgewound
aluminum voice coils for high efficiency. These are slot
loaded to achieve wide horizontal coverage.
Reference Line 210 boxes can be used in a system with a
Reference Line 210D (downfill) box at the bottom of the
line, and one or more Reference Line 210B (LF only)
boxes at the top of the line, to extend the low
frequency line length. This allows a system to be
designed with the desired coverage at optimum cost and
performance. Finally, the use of a separate 3-channel
amplifier module for each box allows for the adjustment
of the level in each frequency band in each box, so that
exceptionally well-balanced response can be achieved
from the first row to the last.
ISP Technologies offers custom designs for Reference
Line 210 Array Systems. ISP will engineer a system using
all specifications of the venue to get the best
acoustics possible for each particular facility. For
more information regarding the Reference Line 210, or
any ISP Technologies product call direct at
248-673-7790.
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