D.A.S. Audio created its Autopol directivity measurement and post-processing platform in 1994 to provide high resolution polar measurements. A key element of the system was a large group of in-house developed algorithms that took care of the numerous computations. This included the PolArray module for performing array simulations with an accuracy unknown to commercial software. Due to the ‘in-house’ nature and the cryptic user interface of PolArray, the challenge became turning the overwhelming amount of information generated into a meaningful tool for the end-user when designing arrays.

Joe Brusi, Autopol director, explains: "People frequently ask us about what the coverage of such and such array would be for a given speaker model. Really, there is no quick answer, since it involves calculating the interference between the different boxes in the array. Even though, there had to be something that I could do for them. PolArray is a somewhat time consuming to program even for just for one cluster. I figured it would take about two months of uninterrupted measurement work to provide multiple cluster combinations for each product."

"Large arrays mean large measurement distances which meant good-bye to our anechoic chamber", states Brusi. "There aren’t many rainy days in Valencia but still, the prospect was not very appealing, even without considering the logistics complexities, so I sat down and wrote some elaborate code. Essentially, the new software works out all the array geometries, and then feeds our existing PolArray base algorithm, which performs the computations using our high resolution polar database."

The end result is a set of tables with 48 different array combinations for each speaker model. The combinations were selected to include a number of boxes from 2 to 5, with splay angles from 0° to 50° - in 10° intervals. The recently-posted user’s manual for ST and R series shows the first appearance of these data tables, and can be found at the Technical Data section of the D.A.S. Website. D.A.S Audio’s marketing director Robert Giner said: "We believe in providing extensive product documentation. Our spec sheets have always been amongst the best and most serious of the industry. These array coverage tables bring product documentation to a whole new level. They are an extremely powerful tool for D.A.S. product users, including rental companies that need to constantly change array configurations to accommodate different venues."

(Ruth Rossington)

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