Reference Line Array Technology

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 4210 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.

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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.