In the late 60’s, bands like the Grateful Dead used any public address (PA) system available, the sound heard by their fans was limited to the knowledge of the sound techs; the quality of those amplifiers, speakers; and the shape of the performance venue.
Bands like the Dead were obsessed with their stage sound and their recordings. The Dead pioneered the use of 16-track recordings in a recording studio. Additionally, in the early 70’s they designed and built a PA (with the help of engineers from Alembic), located behind the band that also functioned as a monitor system. The called the PA the Wall of Sound. The PA was built upon the concept of line arrays (columns of speakers dedicated the vocals and each individual instrument) to control the dispersion of sound across the frequency range for each instrument.
When building the Wall of Sound, the size and speaker selection for each instrument was tested and adjusted to achieve the goal for each band member. The vocal and piano system was designed to fit the wide frequency range needed and the ambience required to achieve natural sound similar to setting in a front room of a house and listening to the singer or piano with no amplification. The final array design for both vocal and piano were very similar. The rhythm and lead guitars needed a strong sound that minimized feedback and phase delay issues. The bass guitar often was muddy in the venues and needed help with clear projection of the mid range frequencies to achieve a clear sound. The Wall was the first sound system of its kind with vocal microphones had a volume control function. This enabled the band to mix vocal sounds on-stage as they played. During performance, every band member had total control of his own instrument and voice volume.
At its zenith, the Wall of Sound included about 600 JBL speakers (15-, 12-, and 5-inch) and over 50 ElectroVoice tweeters, driven by around 50 McIntosh MC3500 and MC2300 amps, one of the most respected amps of its time. This singular work of sound engineering (known as the Wall of Sound) weighed over 70 tons. When assembled, the PA stood over three-stories tall and nearly 100 feet wide. It took a day to build on a given stage. With about 28,000 watts, the Wall was the most powerful sound system available at the time. On stage, sound levels could (but rarely did) reach 127 decibels. That is about the same as standing about 50 foot from a jet engine cranked wide open at take off. I was told by friends who attended Dead concerts the sound could be heard, clear as a glass, a half mile from the stage.
The cost of the Wall, with all its associated expenses, like paying the sound engineering crew, nearly bankrupted the Grateful Dead. By 1975 the Wall had hit the proverbial cost ceiling. It all but disappeared from the Dead shows. Since then, concert goers have seen many a fine system designed and deployed to provide the best possible sound for the money. Every band tries to get it right, but few are able to achieve the clarity of the Wall of Sound.
“At the end of the day, the guy sitting in the third row doesn’t care how long it took to hang the PA, or how light weight it is. He just wants it to sound good, and so do I.” – Kevin Margolin, co-founder, Atomic Professional Audio