by David (Rudy) Trubitt, Sound Reinforcemnt Editor
This article originally appeared in Mix Magazine, September 1993
Venue: Las Vegas Silver Bowl, May 16, 1993
Sound Rental Company: Ultrasound, San Rafael, CA
Dead Engineers: Dead Healy (senior engineer/mixer) and Harry Popick (monitors)
Ultra Crew: Don Pearson, Uwe Willenbacher, Michael Brady, Glen Carrier, Howard Danchik, Michael Shawn Healy
Ultrasound (San Rafael, CA), the Dead's long-time supplier of choice, continues to provide sound for their touring needs. The main loudspeaker system is a Grateful Dead/Ultrasound hybrid, based on Meyer Sound Labs cabinets. The current equipment manifest includes 96 modified MSL-3s and 32 double 18" subs. 12 sections of fork-lift mounted, modified MSL-10s are used for delayed sound reinforcement, and a dozen modified UPAs hidden under the stage provide center fill. Crest amplifiers are used throughout.
The Dead/Ultra team has long worked to tame the acoustics of the large venues the Dead frequents. "Dan Healy (who has mixed the Dead since the sixties) and myself have been working for a long time with the B&K analyzer," explains Ultrasound's president, Don Pearson. Healy describes this tool, in conjunction with very specific equalization, as being able to remove the sound of the room from the listening environment.
Loudspeaker are positioned for coverage, rather than to avoid acoustical problems. "If there is a real bad reflective area, it'll show up during the equalization process and we'll deal with it there," says Pearson. "The spectrum analyzer shows the narrow-band resonances of the room. Almost all ring modes are narrow--1/10th octave or smaller is very typical." By notching these frequencies with parametric equalizers, the system is prevented from exciting the problem bands.
"While the majority of the industry feels that you should EQ each side [of the PA] individually," cautions Healy, "we discovered that doing that destroyed the stereo image." Noise samples are made with both sides of the PA on, providing what Healy calls a 'macro-cosmic' curve of the entire PA and room as a system, rather than a microcosm of each side individually. The analyzer is then used to insure that the left-right filter responses track each other within 1/4 dB.
The equalizers used in the process began life as Meyer CP-10 parametrics, but have since been heavily modified, including replacement of the internal supply with an external one, lowering the noise floor of the input section and converting the boost-cut filters to cut-only circuits offering 28 dB of attenuation at bandwidths less than 1/10th octave.
"Once the band gets on stage and people are in here, there are [additional] EQ changes," explains assistant engineer Uwe Willenbacher. By tracking EQ differences between empty halls and the end of each show, Healy and Willenbacher found they were consistently removing a few unexpected frequencies and adjusted their target curve for an empty room accordingly.
"We also try to track temperature and humidity changes and see how that affects the sound," Willenbacher adds, "so we can predict more than just the normal things." This latest area of research explores the effects of ambient temperature on the loudspeaker cabinets themselves. "I've known it was happening for years," explains Healy, "but on this tour, I've been able to chart and log enough data to show a temperature vs. resonant curve for all these cabinets." Often, systems are noised the evening before a show, perhaps as late as midnight, with tempertaures in the 50's and 60's. However, showtime could see the mercury up to 90. "We found a small change in the subs, but as much as a 5-10% increase in resonant frequency with temperature on the wooden 12" segment of the MSL-3," says Healy. The effect is not particular to MSLs--he notes that other cabinets are likely subject to the same phenomena.
The newest part of the Dead's sound is their stage monitor system. Currently, each band member is evaluating one of several manufacturer's in-the-ear monitors. Harry Popick handles the front line while Michael Brady mixes monitors for the Dead's two drummers on a separate console. Ultrasound's Don Pearson is on hand to help keep both stations running smoothly.
Each front-line band member uses half a Dead/Ultra-modified Gamble EX house board with 10 extra line inputs dedicated to their own independant stereo monitor mix. Each mic or line input goes into the first half of one of the boards. Then, the mic pre-amp out/record-out patch point feeds a mult. These drive the other half of the first board and a multi-pin interconnect cable which is split to the two halves of the second Gamble. Excessive loading of the microphones is thus avoided, as each mic is split only once--to one monitor board and the house console.
Although this dual monitor console setup provides four stereo mixes on the main faders, there's no single master level for each input. "I have to be scanning to make sure everything stays where it belongs," Popick explains. "In an emergency, I can go to the input [of the first half of the first console] and tweak the mic pre-amp gain, unless it's a line level feed, in which case I'd turn it off if something was really wrong."
A stereo drum pre-mix and separate kick, snare and hat are also returned to the two Gamble consoles from the drum monitor console. Finally, each mix also ends up in the console matrix. "If somebody wants to hear Jerry's mix, you can turn it up in the matrix," adds Pearson.
Console outputs feed compressor/limiters, linked for stereo operation. These provide hearing protection and prevent over modulation of the wireless transmitters. At present, only guitarist Bob Weir and several crew technicians are wireless. The remaining band members run their Ear Monitors hard-wired, driven by Crest power amplifiers. Amp outputs are routed to a snake containing 18 pairs of 18 gauge wire, which links distribution boxes spread about the stage. Plugging into the appropriate connector brings up each musician's stereo monitor mix.
At first, each player wore a small belt pack with a passive volume attenuator to set overall level. While convenient, this was the source of some difficulty, says Pearson. "It's hard to find a 1k ohm stereo log taper potentiometer that can take the current from the output of the power amp." The non-linearity of the pots they used made one part of the range sound better than another. Further, says monitor mixer Harry Popick, "I couldn't tell how loud or soft anyone might have their gain. That influences the way they're listening--for instance, how much or little of the room they can hear?"
These problems were solved by using digitally-controled VCAs to control amp input levels, rather than the passive attenuation of amp outputs. The VCAs also display their operating levels for the mixer's benefit, and the band's belt-worn potentiometers no longer carry high-current audio, just a low-current control voltage.
Playing with the Ear Monitors required something of a settling-in period. Last spring Healy noted that, as with normal headphones, isolation from the outside world can be problematic (see Sting story below). "It's much harder to judge overall loudness in the earphones. Also, things like compression and limiting become really critical. We have peak limiters as a safety device and, some people in our scene have limiting and tons of compression in their guitar sounds. Those things together make it a little harder when you're inside the world of earphones."
However, Healy continues, "As a musician, you stand a better chance of hearing what you want, because you're subjected to fewer things outside your own mix. For the first time, you get to determine, pretty much, all of what you hear. That's got to put you in a better mood for playing."
"I think it's dramatically improved the vocals," adds Pearson. "To me, the harmonies are so much better and so much clearer. Plus, all the general background roar in the PA is gone--all the leakage from the monitors into the microphones." Healy agrees that vocal intonation has improved, but cautions that the larger dynamic range offered by in -the-ear monitoring allows the musicians to sing softer but still hear themselves in the phones. However, this more dynamic vocal phrasing doesn't necessarily translate to those listening over speakers, i.e. the audience.
"Ultimately," says house mixer Dan Healy, "I see [in-the-ear monitoring] as good and bad for all of us--the audience, the band, myself. Not having instrument speakers up there is wonderful (the only remaining instrument speaker is a Leslie in an isolation case). If I shut off my sound system, you don't hear a thing except for the drummers. It opened one aspect of sound reinforcement to the theoretical optimum that you dream about. However, it also opens other aspects that are going to require further research."
So, with all this equipment in place, what actually goes on during the monitor mix of a show? The band has experimented with systems that let them mix themselves in the past. However, at present only bassist Phil Lesch participates in his own mix, walking over to operate his section of the monitor consoles during the show. Popick is hands-on for the remaining front-line players. "I'm on the consoles and Don is there to make sure everything is working," explains Popick. "As soon as you stop listening to do something or repair something, somebody [or everybody!] wants something."
Ever-changing musical arrangements makes mixing an improvisation itself. "A lot of it is with Garcia's mix," explains Popick. "If the guys are laying back or just playing quietly but intensely, I may have to keep the mix up. And I find it helps. For instance, If I'm watching Jerry and they're playing certain passages and I kick up the guitar and the keyboards in each ear, I do notice that he'll dig it, he seems to enjoy it. They're playing with him, he can hear it right there. I'm guessing from a musical standpoint--is this what he wants? Sometimes I've done it and he'll say 'hey there's too much this or that,' but sometimes I know I'm right, because I do it and it seems to have a positive reaction."
"You have to understand, I'm perpetually dissatisfied," explains Healy as the topic of vocal mics is raised. "About twice a year, I go through The Great Microphone Hunt. We've gone back to brands we used before, which are pretty good sounding mics. We tried the B&Ks, which are good mics, but because musicians are used to the bass tilt-up when you get inside the pattern of a cardioid mic, the fact that they're condensors causes them to pop and bottom out the diaphragm. That causes them to intermittantly shut off."
His Gamble EX console has a special 4-pole low-cut filter installed by Jim Gamble. "I can make the popping go away without making the voices sound thin. But the instant that it's popping, white noise is coming out of it. So even though you don't perceive it as a pop, there is a severe disturbance in the quality of sound."
On the other hand, Healy continues, "The problem with dynamic microphones is they tend to have high and low frequency problems. First, there's always a resonant frequency in the diaphragm that's not quite high enough to sound good--typically 3 to 5 kHz, some mics are as high as10kHz. The other problem is that they tend to not have real good low end--most of them have transformers built into them to keep reactance off the diaphragm. I've got some that I [run transformer-less] into the mic preamp of the board. That helps, but I'd like to see a dynamic with a small enough diaphragm that the resonant frequency is above the annoying part of the human vocal spectrum--say 10 to 20 kHz. But the problem is that the efficiency would go way down, because you're not capturing enough total SPL to get enough voltage out of it."
"Also," he continues, "I'd want something designed specifically for singing, not announcing or anything else. Mic manufacturers are disinclined to make a mic they can't advertise as usable on everything. I'd rather see sax mics and vocal mics and drum mics. We already have a variety of multi-purpose mics--why doesn't someone come out with a whole line of mics specifically designed to sound good on specific instruments? I know what to do to a mic to make it sound good on sax. Why not build it in?"
One sure thing about the Dead's sound is continued change. "As usual," says Healy, "the Grateful Dead is on the cutting edge of technology. The next generation of mixing boards are in the process of being made." Significant progress has been made by Jim Gamble Associates working with Bob Lentini to develop a fully automated, knob-free console. Infrared touch-screen CRTs will display a flexible arrangement of operator controls, while analog audio will pass through a modular rack containing mixing, routing, EQ and other processing functions. This will allow all band members to mix themselves from their stage positions, while giving mix engineers the option to see each player's current settings.
But regardless of the technology used in the journey, the goal remains unchanged. "You start with the sound system," says Healy. "The next thing is the room the system's in. You work on that until the band steps on stage. Then you make whatever modifications you have to when the band begins to play. Finally, when the audience is in and the show begins, that's the fourth level of what you have to deal with.
"Philosophically, my job is to erase everything between the audience and the band.--you shouldn't be aware that you're in a sports arena listening through a sound system, you're just there with the band. It's a lot of work, and it certainly doesn't happen every time. But that makes the Grateful Dead a spectator sport, because when you do get there it's so groovy that it's worth going a bunch of nights that fall short. So, our audience is rooting for us as much as they're listening. They aren't witnesses, they're participants. And frequently, it reaches the sublime.
"Down through the years," concludes Healy, I've had the outragous good fortune of working with the finest and most creative minds anywhere. The potential success of every show is a product of all of us working together--the entire endevor is a team effort."
The Ultimate Experimental Lab Closes Pro Sound News - November 1996