AES Section Meeting Reports

Central Indiana - March 22, 2022

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The Central Indiana Section hosted Shure's Gino Sigismondi for a presentation on personal or "in-ear" monitoring (IEM) systems. The presentation began with an overview of IEM systems and a history of the technology. As early as 1982 Marty Garcia built custom-fit earphones for stage use, and the first wireless IEM system was employed in the late 1980s using a simple FM transmitter. By the late 90s, custom-built hardware gave way to commercial wireless IEM systems and "universal fit" earphones, greatly increasing IEM adoption. The 2010s saw further advancement in diversity RF receivers, increased affordably, and personal mixing options.

Early in Gino's overview of IEM system architecture, the topic of earphones was breached. Despite seemingly endless earphone options, isolation was presented as the most significant consideration, as it provides the ability to hear a mix while maintaining a reasonable listening levels. This point was reinforced later in the presentation when discussing the dangers of IEM listening at extreme levels, including issues with users removing one earphone. Instead, Gino recommended the use of ambient mics or ambient headphone systems to provide audience feedback to IEM wearers.

From this broad system overview, Gino presented options for IEM system configuration, including receivers sharing a mix via a single transmitter, dual monophonic mixes from a single transmitter, and traditional stereo mixes. While stereo mixes provide a more realistic listener experience, both stereo and mono setups require tradeoffs. Gino then presented a third option where each user receives two separate mono signals which can be balanced at the receiver, giving the user some local control of the mix. The topic of distributed mixing was also introduced, along with potential pros and cons of such a system. Case studies of scenarios for use of each of these options were presented, as well as example systems.

The presentation then shifted to the topic of RF management for IEMs. Gino advocated for the use of inclusion groups, where wireless devices are segregated by type, with each using a different segment of available frequencies. Similarly, wireless mic and IEMs units, and their antennas, should be physically isolated to reduce RF interference. Proper antenna selection can also increase system effectiveness, with directional antennas being a significant way to reduce multipath dropouts. Likewise, antenna combiners can help to reduce intermodulation issues within larger systems.

The presentation concluded with an audience Q&A.

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AES - Audio Engineering Society