also involved in the development of the Grateful Dead's Wall of Sound. In 1980, at the behest of Broadway sound designer Abe Jacob, Meyer Sound repackaged the technology of the UltraMonitor into the UPA-1. This loudspeaker had an immediate impact on theatrical sound, but was also notable for its introduction of the trapezoidal cabinet shape, which enabled the construction of curved arrays (flat-front arrays, in common use at the time, result in substantial destructive interference). A patent was issued for this innovation. The UPA-1 was an inaugural inductee into the TECnology Hall of Fame. Meyer Sound pioneered high-level loudspeaker arrays with the release of the huge MSL-10 in 1981, followed by the MSL-3, a single cabinet (essentially a “slice” of an MSL-10) configurable into arrays of nearly any size. Expanding on the appearance of real-time, dual FFT analyzers, Meyer Sound introduced source independent measurement (SIM) in 1984. SIM allowed sound system operators to use music itself as a test source for the first time, enabling continuous sound system correction over the course of a performance. SIM System II, the second generation of this technology (and the first version practical for widespread field use), won an R&D 100 Award (awarded for the 100 best engineering feats in any field worldwide) in 1992, in addition to the TEC award the original system received in 1986. Meyer Sound introduced the HD-1 studio monitor, a fully integrated self-powered loudspeaker, in 1989. The HD-1 won at the TEC Awards in 1990 in the Transducer Technology category. The release of the MSL-4 in 1994 marked the beginning of Meyer Sound's production of self-powered loudspeaker systems for high-level sound reinforcement, and, over the following years, the company converted their entire loudspeaker product line into self-powered systems. Meyer Sound Laboratories has participated and been featured in several episodes of the Discovery Channel series “MythBusters” involving sound. As a result, Meyer Sound acoustician Roger Schwenke has become an "honorary" member of the MythBusters team. The first MythBusters episode involving the company was “busting” the myth that a duck's quack will not echo. The second time was the infamous “Brown Note” episode, which explored the myth that a person subjected to high levels of very low-frequency sound could experience “involuntary intestinal motility." In the course of busting this myth, John Meyer became interested in the physical aspect of transmission of very low frequencies. Three other MythBusters episodes involving sound tested