Meeting Topic: JBL Case Study: New Transducer and Monitors
Speaker Name: Peter Chaikin, Alexander Voishvillo and Charles Sprinkle, of JBL Professional
Meeting Location: Sportsmen's Lodge, Studio City, CA
The June meeting of the AES-LA featured a presentation from JBL Professional on a new transducer design, as well as the application of that design and related technologies in a new line of studio monitors. Presenting these innovations were Peter Chaikin, Director of Recording and Broadcast Marketing; Dr. Alexander Voishvillo, Senior Manager of Transducer Engineering and Acoustic Research; and Charles Sprinkle, Senior Systems Engineer.
Peter Chaikin started us off with a description of JBL Professional's flagship studio monitor, the M2, a prototype of which was shown at the 2012 AES Convention in San Francisco. This prototype showcased 3 technologies now coming to fruition - a new dual-diaphragm transducer, continued refinement of the speaker acoustics via a new waveguide and sophisticated DSP and electronics for managing the signal to the monitor. Dr. Alexander Voishvillo then took the floor to detail the new transducer. JBL's approach was to use a compression driver design pioneered by JBL, the annular diaphragm compression driver (as opposed to the typical dome diaphragm), and to use two light polymer diaphragms as rather than a single metal dome. This dual driver approach leads to much less dissipated power, increasing the efficiency of the design.
The new dual-diaphragm drivers have been rolled out in JBL's line arrays, as well as the M2 studio reference monitor. A related design, using a single annular diaphragm compression driver but utilizing the same materials as the dual-diaphragm drivers, is being utilized in the smaller 7-series studio monitors. Charles Sprinkle, who handled the acoustic design of the monitors, walked us through the deployment of these technologies for small monitor applications. The target applications for small monitors are in post-production, broadcast trucks and broadcast facilities. These applications require that the monitors fit into tight spaces, have high output (and be able to maintain dynamic headroom), and achieve a high degree of room to room consistency. The M2 studio reference monitor is a 2-way speaker, using the dual-diaphragm compression driver and a 15" direct radiator. Crossovers and EQ are handled externally via sophisticated DSP processing, and the sound from the compression driver is output through an image control waveguide, designed to provide the desired directivity and dispersion characteristics. These technologies are all filtering down into the more affordable and compact 7-series and 3-series monitors.
Our discussion ended with a demonstration of the smaller monitors, allowing those in attendance to experience both their extended frequency response and their uniform dispersion characteristics.
Written By: Daniel Schulz