Building on its original concept of the 4 way Reference Line 4215, ISP Technologies has gone beyond to develop the new High Definition Line™ 4-way line array speaker series that have un-paralleled performance and fidelity. In order to achieve very uniform and extended high frequency response, precision HF horn geometries are required. This results in our offering of three different box types, depending on the vertical coverage required and their position in the line. The HDL 4215N™ is a 12-degree vertical near-field box, the HDL 4215M™ is an 8-degree vertical mid-field box, and the HDL 4215F™ is a 4-degree vertical far-field box.

Because of the inherent problems in some 3-way line array cabinets ISP Technologies decided to tackle that problem and design a true 4-way line array box.  To our knowledge, ISP is the only manufacturer that is making a true 4-way line array box (the Clair I-4 is a proprietary 4-way box, but the 4th ‘way‘ is a built-in subwoofer) that is actually a 5-way system when subs are added. All other line array boxes are 2 or 3-way (the Meyer Milo is 3 1/2-way, in that both 12-inch woofers operate below a certain frequency).

A 3-way line array box is compromised in terms of it’s off-axis midrange smoothness, since the cone midrange drivers must cross over to the HF drivers at 1.2 KHz, typically. At this high of a frequency, the off-axis path difference between the two-midrange driver lines is easily in excess of 1/2 wavelength, leading to a 6 dB or more dip in response in the middle of the midrange. This is on top of the response dip in this range due to the line curvature and cone breakup. The result is that most line arrays suffer from midrange ’suckout’. 

To solve this problem, the ISP Technologies boxes cross over at 750 Hz from the lower midrange cones to four special midrange compression drivers.  At this lower frequency the wavelengths are longer which reduces the path difference at 45 degrees to less than 1/2 wavelength, resulting in a less audible dip.  The result is more consistent midrange over wider angles, with greater clarity on the voice. So no matter where you are sitting, you will not miss a note!

Also, 3-way systems must compromise on the high frequency end since the 1.2 KHz crossover frequency requires use of a large-diaphragm (3 or 4”) driver.  These large diaphragm drivers have either extreme high-frequency rolloff and loss of efficiency, or extreme dips and peaks in the 10 to 15 KHz region due to diaphragm breakup (very annoying to listen to).  The 3 KHz upper crossover in our 4-way box allows use of a 1.75” diaphragm driver, which features response past 18KHz.  The extremely powerful neodymium magnets in these drivers result in a sensitivity of 108 dB @1W/1M out to 18 KHz, which is simply the best performance of any driver by any manufacturer we are aware of!  The use of four of these drivers per box minimizes distortion and maximizes output.  Each box is supplied with 6 channels of the patented high current D-CATä power amplification providing 2000 watts RMS total power per box.

In addition, the boxes are carefully designed with the aid of our proprietary LINESIMä simulation program to achieve smooth response at all frequencies and listening positions when used to our recommendations.  The 12-degree vertical coverage of the ISP boxes means fewer boxes per side are needed.  A 4 box line covers up to 48 degrees vertically.  Competing boxes of this output capability are no more than 10 degrees, and some have as little as 3 degrees, requiring more boxes.  Competing boxes that do have a 12-degree vertical coverage are typically only two-way, with smaller drivers and lower SPL capabilities.  Because of this, ISP Technologies HDL 4215’sä offer the best of both worlds: higher performance and coverage while offering the best value for dollars spent on a system.  Hearing is believing

To schedule a demo of the new HDL 4215 4-way Line Arrayä contact or for more information on this or any product, contact ISP Technologies directly at 248-673-7790, email shellw@isptechnologies.com, or please visit the ISP website at www.isptechnologies.com.