Excellent sound (and extraordinary effort to make it so) is a Grateful Dead tradition.
Hopefully WestchesterDeaD will not mind my quoting him from the LMA comments on 6/18/83:
Next, let me bore you a bit with the technical aspects of the sound system that the DEAD rigged up at SPAC (feel free to correct my shoddy recollection, too). In the case of SPAC, you had the stage area and the roofed audience area (if I recall, the balcony sat on top of a portion of the seated area that was under roof). On either side of the stage, the Dead had their fat assed stacks of Meyer Sound Lab speakers. Phil was about six months into playing his six string bass, and the Dead were using these big huge subwoofer boxes on each side of the stage, in addition to the standard speaker boxes that were sitting on either side of the stage, and also in addition to the wedges that were flown overhead those boxes, stage left and right. This made for a huge low end sound for Phil to drop his bombs, and they were plentiful that night. But wait – that’s not all – they threw a whole lot more in than a set of Ginzu Knives. Just outside of the roofed seating area, you had the lawn area. I happened to be in the lawn area. The Dead flew additional arrays on each of the support columns that housed the balcony, if I recall correctly. These arrays had about four or six wedges each, and right below each of these arrays were a stack of Amps (can’t recall the manufacturer – after all, this was 25 years ago, and I was just coming off a dose at that point). They also had a security dude by our column that kept his eye on the amps so they didn’t get trashed. This layout gave Healy the ability to do these amazing stereo sweeps of Jerry’s guitar – he could have Jerry’s leads fly from one end of the lawn area to the other, an incredibly long distance, with this amazingly large and loud clarity. This really was an impressive sound, and it blended just beautifully with the natural environment, especially during songs like The Wheel, and of course, Morning Dew, which was a monster Dew, mainly from Phil’s six string bombs. The dead really did it up nice that night.
And it is definitely fun to read how tapers (and everyone but special nod to the tapers) literally risked their lives to participate in this event:
More about Spac in '83: