Sound and lighting company CAV has supplied the Defence Evaluation and Research Agency, (DERA), with a Crown-powered Nexo Alpha speaker system which was used to run a series of acoustic propagation tests for the Ministry of Defence. CAV supplied four Alpha S2 subs, eight M3 mid-high packs and eight B1 bass bins which were arrayed eight wide and three deep around a specially-constructed drum, which was laid on its back to fire up into the air. The system was powered by two digitally-controlled racks, each with a Nexo NX241 digital controller, two Crown Ma-3600 VZ and two MA-5000 VZ amplifiers. A number of sensitive B&K 4188 microphones were suspended over the array to record and plot the results for analysis. DERA project scientist Tim Williams explained in more detail. "We set the system up on the runway at Pershore airfield in the Malverns, which is now an official DERA test site, to use the PA as a sound source in order to find out how far sound propagates down the runway. We then put that information into a computer model for propagation, so that when we come to perform tests on the real thing (which I can't discuss for obvious reasons) we¹ll have an accurate model as to how far the sound will travel."
