THE GRATEFUL DEAD'S P.A.
BY MARC SILAG
This article is taken from MUSICIAN magazine Number 36, October, 1981.
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Specs alone have never determined the Grateful Dead's selection of P.A. reinforcement systems. To Dan Healy, the Dead's sound mixer for fifteen years, attitude and philosophy are as important as crossover points and speaker configurations. Over the years the Dead and Healy have made some formidable contributions to P.A. theory and practice.
The Wall ot Sound. the band's first and last excursion into the P.A. business during the mid-seventies was recognized as a major step toward accurate reproduction of stage dynamics and fidelity. The Dead's press kit has nearly as much to say about the band's technical direction as it does about their musical route.
Like many groups who perform in coliseum-type venues. the Dead favor the systems built and maintained by
Clair Brothers of Lititz, Pennsylvania. These systems depend on two Clair Brothers exclusives, the
S-4 speaker cabinet and the 32x6x2 portable mixing console designed and engineered by Bruce Jackson with the cooperation of Ron Bothwick.
The S-4 consists of two 18" speakers. four 10" lo-mid speakers and two hi-mid horns utilizing JBL 2405 Type Drivers using passive crossovers. The cabinets, when suspended from the ceilings of a typical large venue, are strapped in vertical stacks to promote "Line Source Coupling." This affords Healy with more directionality and forward loudness.
Each box requires about 1000 watts of power and Clair provides banks of Phase Linear 700 power amps to drive as many as 64 cabinets, depending on the size and acoustical characteristics of the venue.
The Jackson-Bothwick board is a self-contained unit featuring 32 inputs and six stereo submasters, with two main outputs. Threeband eq is parametric and four effects sends are provided with equalized returns. A unique "bar graph fader" design displays peak _and_ average signal readouts, pre- or post-fader. Steve Dove, an engineer familiar with the board under the duress of touring, has never known one of the six Clair Brothers' boards of this type to fail.
Outboard equipment includes dbx 162 compressor/limiters for each band-width, Crown D-75 power for headset monitoring, a White Spectrum Analyzer/Noise Generator and White 1/6 and 1/3 octave equalizers.
There have been three notable occasions when the Dead have used an altogether different system than the one outlined above. For shows in San Francisco, New York and the Oakland Coliseum, Healy brought three separate audio companies together and fabricated a "super system" so elaborate in its engineering and logistics as to make carrying it on tour an economic impossibility.
Healy's trademark is an open attitude towards new methods of producing full-bodied live sound, eliminating the shackles imposed by electrically produced phase distortion and harsh room reflections that debase the intended sound image. Using documented and patented theories of linear response established by John Meyer and his company, Meyer Sound Labs (MSLI) of San Francisco, the Dead are capable of producing "three dimensional" live reinforcement. Healy is the only sound engineer we've run across who uses the term "holographic" in discussing his work.
McCune Audio of San Francisco supplies the Dead with stage stacks consisting ot twelve 12" woofers, six mid-range horns and thirty tweeters per side. The system, known as the JM-10, incorporates Meyer's theory of linear response in which accurate imaging is dependent on the electrical pre-distortion of the P.A. signal before it reaches the speakers and drivers. In the case of
equipment listed here, speakers and drivers are manufactured in Europe to Meyer's specs. By carefully matching each transducer to the circuitry employed to pre-distort the signal, it is possible to compensate for phase distortion created when the transducer changes electrical energy into acoustic energy. Elimination of phase distortion is the prime mover of this system and both the JM-10 and the Bill Graham Presents System 80 that flies over center stage are "time corrected," using another design of MSLI the Group Delay Equalizer. The GDE shapes the wave forms to be projected by the system(s) by delaying specified frequencies within a given bandwidth, allowing all frequencies to arrive at the listener's ear at the same time. This also makes room reflections more controllable, and the ping-ponging of certain frequencies in a room is greatly reduced. The System 80 is a cluster arrangement consisting of sixty 12" woofers, twelve MSLI horns and twenty-four Heil tweeters. The third company using Meyer's technology is Ultrasound of Larkspur, Calitornia, who provide sub-woofer assemblies Meyer designed for the sound track of „Apocalypse Nowâ€. These cabinets house 18~' ferro-fluid speakers to handle the low end ot the Dead's sound.
In the house, McCune equips Healy with a 22x4 mix console with 3-band eq, augmented by a Tangent 2402 mixer for the drums. Although outboard eq is available, Healy uses it sparingly. Healy claims the only usable form of eq comes in the selection of placement of stage mics. No special outboard equipment is used aside from some special effects, the nature of which Healy would not divulge.
The sound of this system is extraordinary. It played a major role in the recording of the recently released live Dead LP, in that Healy relied heavily on room mics in the mix of the album. For the audio-conscious Deadheads of the world, it is Healy's hope that such a system will eventually join the Dead on tour.
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Attached is the article by JBL on Clair Bros S4 system:
View attachment A%u002520JBL%u002520Installation%u002520-%u002520Clair%u002520Brothers%u002520and%u002520JBL%u00.pdf