David Missal of Sennheiser speaks about wireless microphone systems and the University of Hartford
On the evening of November 17, 2010, Hartford AES welcomed Sennheiser's David Missal for a lecture on "RF Theory & Application". Missal's presentation, an abbreviated version of his 8-hour "RF Wireless Sound Academy," focused on the technical architecture and practical implementation of modern wireless audio systems.
David began by explaining the challenges of the "crowded spectrum". He discussed trends of RF use in television, FM radio, mobile phones, and law enforcement, and advised that engineers conduct research on local RF laws and use before tuning their wireless mics.
When laying out an RF system, Missal reminded students to consider important technical factors, such as the frequency-dependency of wave propagation. Longer paths, David suggested, should utilize lower frequencies to minimize blips and dropouts. Missal focused on the details of intermodulation, and demonstrated how the proximity of transmitters can greatly affect system performance. When transmitters must be placed side-by-side, he advised that they be tuned to distant frequencies to avoid interference. David also demonstrated the negative effects of body absorption and antennae shorting (due to bending and exposure to perspiration) on signal integrity. Concepts of antennae diversity were covered, including the internal switching of receivers used to maximize performance. Missal also discussed proper gain staging and antennae selection and gave tips on microphone and transmitter placement.
Sennheiser is a world-leading manufacturer of professional microphone and monitoring systems. Visit them at www.sennheiser.com
