(Editor's Note: In addition to the information provided below, JBL has just posted two Tech Notes regarding the PD Series, explaining its low frequency technology (PDF Format) and mid/high-frequency technology (PDF Format).)

JBL Professional has introduced the Precision Directivity (PD) line of loudspeakers for arena, stadium and other large fixed installation applications. The new loudspeakers have been installed recently at American Airlines Center, a new arena in Dallas (design by WJHW, Dallas), and the new Ralph Engelstad Arena in North Dakota (design by Impulse Group, Minneapolis).

Seven mid/high, mid bass and low-frequency models currently comprise the PD line. Mid/high frequency loudspeakers utilize a new co-axial design, with specific coverage angles that allow the sound to be aimed at individual sections of the audience area. Low-frequency loudspeakers have been designed to distribute LF/bass energy evenly, with this energy also able to be “steered” at specific areas.

Low-Frequency PD Systems

Three modular forward-steered systems, including PD162, with six 12-inch drivers, reproducing the 125 Hz to 300 Hz upper-bass range. PD125 has two 15-inch drivers and is designed for low frequencies in the 50 to 250 Hz range. PD128, with two 18-inch drivers per enclosure, works in the 30 Hz to 125 Hz lower-bass range. Steerable arrays are formed by using individual enclosures in multiples and applying the proper signal processing.

PD162

For PD162 mid-bass arrays, the steering is accomplished by progressively delaying each pair of low-frequency transducers to a reference plane that is perpendicular to the direction in which the array is being steered. To maintain wide horizontal coverage, the array is kept as narrow as possible in that direction. The transducers are mounted "motor out”, reducing the horizontal width of the array and to assist in cooling, which reduces power compression.

PD125

The PD125 works in a fashion similar to that of the PD162, but with a different mechanical configuration dictated by the larger size of its 15-inch drivers and their requirement for greater internal enclosure volume.

Due to longer wavelengths at frequencies where the PD128 Subwoofer Array operates and the larger enclosure volume required for response to 30 Hz, a different configuration is required. Greater spacing of the elements is necessary to effectively steer the energy since the wavelengths involved are longer. As with the upper-bass array, the lower-bass array is forward-steered by progressively delaying each set of modules.

PD128

The two arrays can be used to compliment each other as they are optimized in their physical arrangement to effectively steer their main energy lobe and to accurately reproduce program in their frequency range.

The PD128 and PD162 are intended to work together to form the subwoofer/low frequency and mid bass sections of a four-way system when combined with PD Series mid/high enclosures. The PD125 forms the low frequency section of a three-way PD System for applications where the 30 Hz extension of the PD128 is not required.

Mid/High PD Systems

The PD764 60 x 40 and the PD743 40 x 30 are devices are the first two mid/high Precision Directivity speaker systems. Co-axial arrangements allow much smaller frontal area than the traditional designs with HF and MF elements adjacent to one another, which means more compact arrays are possible. Since a co-axial design is inherently axis-symmetrical, the problem of an asymmetrical polar pattern caused by physical offset between mid and high frequency drivers is avoided.

PD764

PD743

These loudspeakers incorporate JBL’s new 2430 compression driver, 108 mm (4.25 in) in diameter and with a high-energy neodymium magnet. The very small cross-sectional area of the 2430 drivers allows the HF section to be acoustically transparent to the midrange wavefront.

To obtain the required midrange output, the system uses JBL's latest generation dual-voice coil Neodymium Differential Drive technology. The model 2250 high-power 400-Watt, 8-in transducer delivers high output but with smaller size and lower moving mass preferable for midrange reproduction. This allows for closer driver spacing and results in a system with very high output .

"PD Series is the result of a fast-track development program by the JBL Custom Shop and JBL R&D in conjunction with some of our key customers and the Harman Professional Projects Group," explained JBL Professional President Michael MacDonald. "Last year, in discussions with the designers of several large arenas, we felt we had a new approach to help them design large speaker systems with predictable and manageable coverage patterns. Control and intelligibility are the results of the new PD Series."