The Secrets Of Pink Floyd’s Quadraphonic PA

After 42 years and 6 months, I finally got the chance to speak with Roger Waters for a minute about one of the most incredible, potentially disastrous, nearly fatal, and little known events to happen in rock history; the nearly complete destruction and rebuild of the Pink Floyd sound system on the Dark Side of the Moon tour. On March 5th 1973, Pink Floyd played Cobo Hall in Detroit. About half way into the show, with the sound system at full volume and Alan Parsons at the FOH console, according to Roger when we spoke yesterday, a ballast weight fell from the rafters into a flash pot and caused a massive explosion on stage. The weight itself was blasted into small chunks of flying shrapnel. According to what I was told by the Floyd crew at the time, the explosion ripped a hole in the stage and threw chunks of wood 30 rows into the audience. Roger and Alan Parsons told me separately, that one man was hit in the chest by a chunk of plywood and critically injured. It was a miracle that none of the band or crew were killed. The force of the explosion blew every single driver in every single cabinet in the PA system! Let that sink in for a moment. This was one of the largest PA systems ever constructed to that time, and according to the crew, chunks of drivers showered down on the first ten rows of the audience. I can't imagine their shock. Something that I didn't find out until yesterday from Roger, was that immediately after the explosion, the Floyd crew scrounged together some spare cabinets and built a tiny system, one cabinet per band member, and they finished the freakin' show! That was the beginning of a heroic effort on the part of two sound crews. I was a roadie for Heil Sound at the time. Heil Sound was one of the largest PA companies in the US with two large systems, one for Humble Pie and one for The Who along with lots of other gear to put together smaller one-off systems. We were also one of the only JBL speaker reconeing companies in the mid west. It turned out that Bob Heil had met Pink Floyd some months earlier when he flew to London to purchase a Mavis console for the two big systems. So Bob knew who Pink Floyd was, but most of us on the crew had no idea. The night of March 5th, someone from Pink Floyd, somehow got Bob's home phone number (communication was NOTHING like it is today!) and told him of their plight. Bob rallied a crew, me included, and the next morning at dawn we loaded up a straight bed truck with loads of 15" JBL speakers along with boxes of tweeter drivers, dozens of drivers in all and four Heil 2X12 speakers and a pair of Phase Linear 700 amps, and headed for Kiel Auditorium in St. Louis, Pink Floyds next stop on the tour. We met the Floyd crew at the stage door and formed a plan. They would bring in the cabinets and begin constructing the system as planned and as they built the massive stacked system, we would remove the backs from the cabinets and replace the blown drivers with brand new JBLs. If I recall there were only four of us Heil roadies on the gig, so the idea of replacing an entire sound systems driver contingent was really really a tall hill to climb. My job was a little different from the other three. I had to run a thousand feet of speaker wire and set up the Heil quad speakers that Pink Floyd used for the rest of the tour and assist some guy named Alan Parsons to set up and run a little TEAC 2340 quad tape machine. (The Heil speakers are coincidentally in the Rock Hall of Fame, but not because they were used on the Dark Side of the Moon tour, but just because Bob is Bob.) We went to work as quick as we could and worked right on through the day without a break. No lunch, no nothing. Just get the job done. Five O'clock came and the band came out to do a sound check, except there was no functioning PA yet, so they just played with their amps on stage and maybe a little bit of monitor. Nothing out front. I had no idea who Pink Floyd was and from my perspective out front, I thought they sounded kind of sleepy. Ha! 8 O'clock came and went and we weren't ready. 8:30 and we still didn't have the system put together yet. Around 9:00PM, someone made the call to open the doors and people streamed in, excited to hear some band I had never heard of. Odd. Around 9:30PM the house lights went down and a few seconds later, the curtain started to climb up out of the darkness and the PA EXPLODED again, but this time with the first strains of a kind of music that I had never heard before, I was shocked. After about a half hour set, the band took a few minutes intermission. When they came back, they played The Dark Side of the Moon! OMG. All of the tweeters were not yet replaced and we still had a crew member standing on each stack, screwing the backs on cabinets, but the sound was literally breathtaking. The scene was epic. I found myself standing next to Alan, while he smoothly swung back and forth between the FOH console and the little TEAC tape machine. He had gobs of white leader between each sound effect and in near total darkness, would fast forward the tape to the next SFX and cue it up. Then back to the console for a vocal ride or guitar ride and then back to the play button on the little tape machine. I say I found myself because at the first notes of the first song, I began to have an out of body experience like I had never experienced before. I had no idea who Pink Floyd was and was in no way expecting the sonic feast I was experiencing. I was an audio snob up to that point, and believed I knew how sound systems should sound. Oh no, I had no freakin' idea how sound systems should sound. That much was clear. The Pink Floyd PA, with brand new JBL speakers and drivers, and The Dark Side of the Moon flowing from it, was unlike any I had ever heard or have heard since. I was standing right in Alan Parsons sweet spot and the balance of the quad system was unbelievable. There were voices in my head. There were bells sweeping through my body and out the other side. At one point, a combination of exhaustion and elation almost cause me to lose my balance and I had to lean on the table, still being careful not to get anywhere near that tiny little player. When the show was over, I gathered myself and we Heil crew loaded our truck with our tools. I shook Alan's hand, may have got a hug from a Floyd roadie and almost without a word, we drove off into the night, only suspecting the profound musical event we had just witnessed and helped save. With every passing day, the events of March 6th, 1973 have become more profound to me. Kiel Auditorium is long gone, Many of us on the two crews are long gone. But the memories are as vivid as last nights sunset.

I was technical manager at Mayfair Studios during the recording & mixing of The Final Cut. When Pink Floyd were in, all our studio monitor power amps had to be replaced with Pink Floyd’s Phase Linear Amps.

Somebody give this man a cigar, doing good work here Mr. Hewitt, I hope someday I will be able to hear this rig in action!

Oh the nostalgia... I entered the live sound game mid/late 70's and remember very well those Martin "W" bins and by that time we had the phillyshave mids and Mida mixers. The other Quad mixer of that time was the MAVIS, built like a tank and superb.. designed by one Bill Hough, who also did lots of mods for Deep Purple and also made some really cool parametric EQs for my FH Midas ( I regret not pulling at least a couple of them before I sold the desks).. Great to see all that old vintage gear lovingly cared for. Oh yes.. nostalgia ;-)))

I experienced hearing this PA at the Pink Floyd Milwaukee stadium concert and it blew my mind when the audio started to rotate around the stadium.

Legend has it, Mick ‘The Pole’ also made some ‘colorful movies’, back in the 70s …

Wow! This is a legendary and groundbreaking PA! Wonderful too see it being restored.

I got to hear this system several times. This and the Dead's Wall of Sound were the best I ever heard in that era, thanks! 👍👍👍

I still remember the fantastic quad sound featuring Rick’s synth solo intro on Shine On You Crazy Diamond at Knebworth back in 1975, still makes the hairs rise on my arms just think about it. Great video, it’s good knowing the history of Pink Floyd 🤘

Those three words: "Pink Floyd, London" as iconic and as conquering as SPQR.

Excellent video! One sidenote. Modern PA systems have more then sufficient dynamic range, the problem is the new generation of digital mixers have a compressor on each channel and thanks to the hype over compressors on, for instance, youtube. The new generation of soundengineers compress everything to an extend that they kill the musicality. I hear it over and over again at festivals. Being a soundengineer from the late 80's I've seen this compression hype slowly becoming a common practise. Back in the days you had 3 or 4 dbx160's (if you were lucky) and could make a very good sound for a 30 input channel band.

There was a time in the late 80s where Dan Healy (Grateful Dead FOH) would set up rear speakers in the upper deck of the arena, and they would run the normal PA for most of the show and then kick on the rear speakers during the "Drums and Space" segments. Suddenly these crazy beats and weird noises would start spinning around the room. It was particularly enjoyable under psychedelicized conditions 🤪

I mixed Blue Oyster Cult on a later custom Floyd desk, a Midas with all the markings in colored phosphorescent paint. It was a two piece affair with dueling black lights and, yes, all the lettering glowed in the dark!

I saw Floyd at the East Town Theater in Detroit during the Ummaguma Tour and they had Quad Sound with speakers all over the theater; front, rear and above and a joy stick controller to swirl the sound. There was a large 'control pit' in the center on the floor. It blew everybody's mind when a sound bit of a guy chasing a fly around with a newspaper ended with a smack down and a satisfied got you, went all around the theater. Interstellar Overdrive was amazing.

Always happy when gear like that ends up in the right hands. Very cool.

I'm drooling... need a bib. Eye AND ear candy! A quad reel to reel... sweet memories. American Express had it wrong. THIS is priceless.

This was fascinating. Loved it. My 1984 Sennheiser 409, that I use as my drummer's vocal mic, is the last microphone I would ever sell.

Would be great if Nick Mason’s Saucerful of Secrets did a gig with this setup.

It`s avery nice history about PINK FLOYD gear sound...STanding ovation...¡¡¡ YEAH...😎😎😎

Thank youuu! For a musician and live sound engineer who had a 2 year phase of deep, deep Pink Floyd listening experience and cherished them ever since and is a serious analog gear enthusiast, this was beyond epic. My mouth still wide open.