Here is my theory: In the sixties music sounded like sixties music, not entirely by choice but by technology. In the the time of Jimi Hendrix, Janis Joplin, or the earlier Stones, concert promoters and musicians wanted two opposite and opposing things: great sound in a transportable form factoring in fantastic loudness for huge crowds. And here, Hoffman's iron law of loudspeaker building kicks in again: Of those three, choose two. When reviewing my sixties record collection of live music, the choice was clear. Screw the sound. So, huge crowds and distorted, ear-wrenching sound it was.
As Brian Anderson elaborates in his extremely well researched article "The Wall of Sound", back in 1969 there was a group of people getting together in Novato, California who wanted a different choice. Great sound and huge crowds and what they came up with clearly put transportability to its limit.
Bob Weir, Jerry Garcia, and Phil Lesh the members of the then emerging band The Grateful Dead gathered together a loose circle of sound technicians, audiophiles, and other followers who were to become an integral part of the band’s emerging success.
According to Rick Turner, who designed amplifiers for large-scale public announcement systems, they talked about many things that day, “the technical, the musical, and the exploratory”.
At some point in the meeting the talking points converged to a fundamental crisis. the music played at large rock concert: The sound quality of The Dead's concerts at what were becoming larger and larger venues was crap. While rationalized into a statement against the Vietnam War and other things wrong with humanity the distortion, the noise, the messiness coming from very rudimentary PA systems cranked up beyond their capability was messy, hard to bear and dangerous to human hearing at best.
This was about to change and help came from The Dead’s friend, sound engineer and previous benefactor Augustus Owsley “Bear” Stanley III. At the time a “Breaking Good“ type of character, Bear as a gifted chemist, was renowned for his high grade LSD that he could spin out at unlikely quantities which had made him independently wealthy to a degree that he could further his other passions: Sound and music. And he was pure genius at everything he touched.
Bear had a rather intimate relationship with sound equipment. Having financed the Dead`s early tours he was once reportedly found weeping next to a pair of speakers that had blown apparently with a broken hard sobbing: “I loved you, how could you fail me”.
Bear took lead in fixing the terrible sound of the sixties and seventies rock venues with a simple approach: The sound needs to be behind the musicians, not in front of them. That way he could do away with the need for monitors and not deal with fixing feedback causing time delays due to the travel time of sound on huge stages.
The first challenge this brought on was that of feedback. Sound enters a microphone, is converted into a signal, this signal is amplified, sent to speakers and returns back into the microphone to be amplified again.
The way this feedback issue was addressed was to use two identical microphones. One would be sung or played into, the other would be at a small distance, and pick up the background noise. The two signals would then be subtracted and all that would be left, in a perfect world, was the singing or the instrument.
The vision of moving the speakers to behind the band was fundamentally for the musicians and the audience to hear the same thing.
Overruled at first and deemed impossible by the collective in attendance, the outcome of this meeting after it seeped into the realm of first what's imaginable and second what's possible.
By 1973, the band was playing with a prototype kind of wall that proved the key concept; to place the main speaker system behind the band and be able to deal with the feedback in an effective way.
This encouraged them enough to take a major leap into what was to become the worlds biggest live concert PA system ever: The Wall of Sound:
As shown in the video above, the band consciously traded off great sound at great SPL at the expense of transportability, and the Wall of Sound was so huge that it could not possible be transported, set up, and torn down between gigs on time to be ready for the next. There were two walls of sound needed that were alternated between concerts with two crews to set-up, operate and tear down.
Even with that division of labor, the task at hand was mind-boggling. One crew would get up at 6 am and unload, build and test their wall to just be ready for the evening concert, they would operate the wall during the concert, then party some, and get to bed by 4am or later in time to get up at 6am again to dismantle the wall and load it onto trucks. By that time the band had already moved on to the next location to play with the second wall.
The technical details of “The Wall” were mind-boggling: While not being called that at the time, the wall was the first line array, a speaker setup that uses many loudspeakers fed with the same signal to produce a more directional and efficient sound field through acoustic lobing.
With around 600 speakers and 90kW of power, the Wall of Sound was really remarkable in its sheer size. Two separate setups are reported:
189 300-watt solid-state and three 350-watt vacuum tube amplifiers generating a total of 26,400 watts of audio power. 604 speakers total.
2586 JBL speakers and 54 Electrovoice tweeters powered by 48 McIntosh MC-2300 Amps (48 X 600 = 28,800 Watts of continuous (RMS) power).
The sound system provided high quality sound at a distance of up to 180m after which, regardless of the quality of a sound system, wind and air turbulence will always start to deteriorate the sound.
The wall of sound also incorporated Quadrophonic sound technology. But rather than serving as a spatial illusion the four channels were used to encode the different istruments and send them to their own separate stack of loudspeakers. This made recordings of the Grateful Dead concerts a challenge as out of phase channels needed to be mixed together into a stereophonic experience leading to tizziness in the sound due to narrow cancellations and super impositions.
Wikipedia chalks the Wall of Sound up as being the second largest portable sound system ever built, but makes no reference to the system, which might have been larger, and how that may have been measured.
The 1970s fuel crisis finally put an end on this behemoth undertaking. Due to various frictions amongst the band members, the rising cost of fuel and manpower contributed to the band´s band's “retirement” in October 1974. The Wall of Sound was dismantled, and when the Dead began touring again in 1976, it was replaced with a more logistically practical sound system. The system lived on as piecemeal donations to friends in need; other Bay Area bands such as The Jefferson Airplane, Hot Tuna, and they themselves re-purposing various elements. Recordings abound of The Dead recorded while using the system as well.
If you want to read more about the Wall of Sound from someone who has spent a lot of time researching this, I highly recommend you pay Brian Anderson`s article on Motherboard a visit.
Arved Deecke is founder of the Danish / Mexican Loudspeaker company KVART & BØLGE that makes audiophile quarter wave loudspeakers and sound systems at a price anyone can afford. In his free time he blogs about all things related to sound, music and audio.
