Svn-Aud-Con founder Don Davis has always said that it takes about 10 years for a good idea to become widely accepted by the audio community. I have personally witnessed this in the PZM microphone, coaxial loudspeaker and time/frequency domain measurement systems.

The Bessel array also belongs in the category of “sleeping giants.” This Tech Topic should serve to familiarize our readers with the principles of the Bessel array, and spawn some ideas on applying it. This simple, yet effective wiring technique can solve some array problems in the simplest and most cost-effective manner. pb

The Bessel Array is perhaps one of the biggest “sleepers” in the world of audio. While it has been around for years, it has not enjoyed widespread use. It is possible that much of the audio community is unaware of its existence.

In short, a Bessel Array is a wiring configuration that makes multiple loudspeakers radiate in a pattern similar to one of the loudspeakers used individually. Invented and patented by the Philips Corporation, there are many possible configurations. Featured in this Tech Topic will be a 5-loudspeaker and 25-loudspeaker configuration.

We have two Bessel arrays at Syn-Aud-Con. Our 5-loudspeaker unit is commercially available from J.W. Davis and Company of Dallas, TX. The 25-loudspeaker model was recently handed down to me from Don and Carolyn Davis, and was built a number of years ago by Mike Lamm, now of Atlas/ Soundolier but at that time with J.W. Davis and Company.

Both the 5-loudspeaker and 25-loudspeaker arrays have individual tuned compartments for each transducer

There are many occasions where it is desirous to utilize multiple loudspeakers for an application, but without the coverage pattern modification that results from close-coupled multiple transducers. An example might be the need to place 5 subwoofers side-by-side under a stage. In this orientation, the horizontal coverage pattern would collapse (become narrow) and the vertical coverage would be very broad, the exact opposite of the desired coverage. Bessel wiring can permit the use of the 5 devices, yet with the radiation pattern of a single device.

When compared with the single device, a Bessel array yields five times the power handling and a 2/3 increase in sensitivity over a single device.

The Bessel array is a patented technology. If you wish to build a Bessel array for commercial use, you must pay a royalty to Philips Corporation, or purchase a licensed unit from the J.W. Davis and Company. One may be built “royalty free” for personal use.

You may also want to read these related stories: