John Meyer designed and built PA systems for the Grateful Dead and many other seminal 60s / 70s bands, which in time led to the formation of Meyer Sound Inc. Possibly the most continuously innovative loudspeaker manufacturer in the world, Meyer Sound pioneered the use of self-powered loudspeakers (i.e. speakers that have internal power amps) for concert use and major sound reinforcement applications.
Meyer Sound dominate global theatre audio as well as having huge presence in installation work and touring sound. Frighteningly expensive but astonishing audio and engineering quality - you gets what you pays for!