D. B. (Don) Keele, Jr. and Hugh Sarvis explore wedge loudspeaker design
New York, NY – October 24, 2017 – During the recent 143rd AES New York 2017 convention at the Jacob K. Javits Convention Center, D. B. (Don) Keele, Jr. of DBK Associates and Labs and Hugh Sarvis, Managing Director of the Loudspeaker Division at PreSonus Audio Electronics presented a white paper that explored the design and implementation of a two-way, constant-directivity wedge loudspeaker system. The presentation was given by Don Keele, Jr. and was well-received as a thorough examination of the many considerations for its implementation in line array configurations.
The paper describes the design and implementation of a two-way constant-directivity wedge loudspeaker system that houses a single 12-inch woofer and eight 2-inch drivers in a 20-degree circular arc mounted on a segmented curved baffle that covers the LF driver. The curved baffle is open on either side so the acoustic output of the LF driver and ports can escape to the outside. An individual system comprises a 20-degree wedge box encompassing a four-channel plate amplifier with two bridged channels driving the woofer, and the two other channels individually driving each half of the eight-driver array. This basic wedge enclosure is then used in multiples to form larger circular-arc arrays ranging from one to six boxes—making arrays that provide various vertical beamwidths in the range of 15 degrees to 90 degrees. Appropriate amplifier gains are chosen to smooth the directivity and enhance the polar coverage for each array size.
Reflecting on the presentation, Keele offered the following thoughts, “The two-way, constant-directivity (CDL) wedge loudspeaker offers a unique approach to addressing a variety of commonly encountered challenges in loudspeaker / line array design. At AES, we explored the system’s design, its implementation, power amplifier considerations, array shading, delays, array simulations, and system measurements. We had a good, attentive crowd and I believe we delivered a clear perspective on the system’s possibilities and advantages.”
Hugh Sarvis commented on his involvement in the project, “Working with Don on this project was a terrific opportunity that broadened my approach to system design. Taking advantage of our design tools and extensive lab facilities, my associate Norvin Roessing and I coordinated the 3D modeling of the loudspeaker and together, we built a prototype that, I believe, offers tremendous potential. Whenever loudspeakers are placed in front of other loudspeakers—as is the case in our constant-directivity wedge loudspeaker design—reflections and other anomalies require careful attention to sort out potential issues. I believe our approach is unique and has the potential to re-define loudspeaker design.”
Founded in 1995, PreSonus Audio Electronics, Inc., is a leading designer and manufacturer of audio-recording and live-sound software, hardware, and related accessories. PreSonus’ software, microphone preamps, signal processors, digital audio interfaces, digital mixers, control surfaces, loudspeakers, and other products are used worldwide for recording, sound reinforcement, broadcast, sound design, and Internet audio. For additional information, visit www.presonus.com.