Editor’s Note: This article originally appeared in the February 1981 issue of Recording Engineer/Producer magazine, the forerunner to Live Sound International.
With inflation spiraling ever upwards, not many groups can afford to tour extensively and fill the large arena so popular a few years back. Bruce Springsteen is one of those superstars who can sell out 16,000-plus seat venues for four nights in L.A. and still turn many thousands more away.
Springsteen’s music is hard to reproduce live, especially at an in-the-round venue such as the Los Angeles Sports Arena. He layers his instruments, but many overlap into the same areas. On record they produce textures of sound; in concert the instruments can easily mask or muddy one another. The high energy level of a concert performance – as well as the proper musical balances between players – must be maintained throughout a wide dynamic range, as the repertoire shifts from exploding, steamrolling rockers to down-to-earth, romantic street ballads.
Springsteen insists on the best sound reinforcement possible and schedules a sound check for every afternoon at four o’clock; regardless of whether it’s an opening night or a repeat performance. He’ll walk through every section of the arena to ensure that patrons in the least expensive seats will be able to see and hear as well as those in the most sought-after front-row areas.
No seat for the L.A. Sports Arena show was to be more than $12.00. When Springsteen heard about scalper’s prices of $50, $100, and $200 a seat, he made a public announcement to the audience during each of the four shows about a pending bill in the California legislature, which the fans should support in order to put an end to the “rip-offs” in the concert business. With his own group — the E Street Band — and road crew, he spared no expense in these days of industry cutbacks by providing everyone with their own rooms at fine hotels along the itinerary. This fact is brought up only to point out the climate of the concert presentation, and the family feel and dedication of all involved to provide audiences with the best possible entertainment under what proved – at least in L.A. – to be severe, adverse conditions.
The PA company chosen to do the sound was Clair Brothers, of Lititz, Pennsylvania. Australian-born Bruce Jackson, whose credits include Elvis tours from 1971-1977, Three Dog Night, Cat Stevens, Rod Stewart, and more with Clair Brothers, is chief sound engineer. His crew includes Chris (C. J.) Patterson doing monitors, Stan Horine, assistant sound engineer, and “Midget” and Tony “Brokowski” Gallicchio on set-up and maintenance.
Several weeks before the scheduled appearance in Los Angeles, Bruce Jackson, Springsteen, and George Travis, who is in charge of tour production, visited the Sports Arena to determine whether or not they really wanted to do the show there at all. Springsteen didn’t mind the design of the hall, even though it’s not as good acoustically as the Forum, the usual choice for large music concerts. “I didn’t actually do any acoustic testing the day of our visit,” says Bruce Jackson. “It was just a matter of identifying a sense of latent problem areas based on my experience with rooms like that.”
In the upper concourse there is a high, stark concrete wall that runs all the way around the building.
The hall is oval-shaped, and at both ends are great arcs which focus the reflected sound; the stage is positioned right in the center of the focal point of one of the arcs. Any sound from the stage speakers bounces directly back on to the stage area and makes any on-stage control unpredictable because of leakage problems and abnormal feedback potential. This high-level concourse is reinforced by another concrete concourse located one seating section below, and which also extends all the way around the building. At the lowest level — floor level — is the foyer or entrance area of the coliseum. The foyer is only separated from the main room by structurally functional concrete pylons, which serve to hold up the building and allow direct access to the outer area. This latter area is constructed almost entirely of tile, concrete, and glass.
In essence, the main arena is acoustically coupled directly to an echo chamber that runs around the perimeter of the main room. The intended remedy was to hang heavy drapes on all of the large, reflective concrete surfaces and between the main room and the foyer. The latter idea would, to a degree, isolate the two areas, and reduce the amount of sound transfer from one to the other. Unfortunately, drapes of the appropriate length couldn’t be located, and a compromise had to be struck. In addition, the fire marshal at first objected to the drapes on the grounds that they were a potential fire hazard (he tried to burn them, but they were fire retardant), and also because they could impede entrance to and exit from the hall.
However, since the drapes were approximately three feet too short, the objection to impeding exits was dropped, although the area was not sealed off as completely as planned. The drapes were rented for the four-show Los Angeles engagement from West Coast Theater Supply at a cost of around $7,000.
Another potential source of problems was sound bouncing around the inside of the metal ceiling. To break up these reflections, drapes that are normally hung as a backdrop for the stage during performances to only the front of oval-shaped halls were pressed into service (Figure 1). Each drape measured approximately 50 feet long by 25 feet wide. As far as possible, within limitation of the ironwork located in the ceiling, positioning of the drapes approached all the way around the stage, placement being almost directly above the house console to break up reflected sound coming from the back of the room.
“The curtains helped, but it’s very hard to document,” Jackson offers. “It did damp things down substantially. Closer to ideal would have been desirable, but when you’re working with the laws of diminishing returns, it’s a tradeoff in terms of how much you spend versus how much you get back in better control and better sound.”
According to Jackson, “Placement is a matter of putting power where it’s needed. There’s no set configuration; the setup changes from place to place depending on the parameters of the building.”
There are several speaker designs developed by Clair Brothers, each built for a specific use. The basic composition of each cabinet will be discussed, but a listing of the specific components is proprietary. The only exception is the house speakers, conceived by Gene Clair. Their S-4 speaker configuration contains:
• Two K-151s for bass (18-inch JBL)
• Four K-1100s for mids (10-inch JBL)
• One TAD 4001 compression driver for highs
• One JBL 2441 compression driver for highs
• Two JBL 2405s for super-highs
The K-151s go from 20 to 200 Hz, and the K-110s from 200 Hz to 1.2 kHz — all are 18 dB per octave roll-off. The drivers run all the way out, with the super-highs coming in at 8 kHz. It’s a four-way system driven by a tri-amplification system which will be discussed later. In addition to an electronic crossover, the horns have a passive, high pass network to protect them from excessive excursions. There’s no high-end roll-off for the horns, and the super-highs are passively crossed over with the high-pass.
The TAD and JBL drivers are used together because they each have inherent deficiencies and strengths which tend to balance each other out. These complimenting deficiencies stem from the compromises that must be made in state-of-the-art driver design. For example, to gain higher frequency response, one manufacturer broadened the Q or bandwidth of a diaphragm resonance and moved it up in frequency to reinforce the high-end. Another manufacturer took this resonance and moved it out of the audible range by reducing the diaphragm mass. Each of these approaches has its own subset of effects, and an analysis of them would be an article in itself.
The Beryllium diaphragm of the TAD driver is sensitive to large excursions, and “tends to bite the dust, if asked to do so,” according to Bruce Jackson. The TADs are protected by an additional LC high-pass circuit set up close to the electronic crossover point.
A Clair Brothers employee in the speaker department noted a strange resonance when testing the new JBL 2441 drivers and discovered that a drop of nail polish placed on the back of the diaphragm damped out the resonance. (JBL has since included such a procedure in its production process.)
As Jackson explains, “Over the first weeks of the tour I was having trouble with the system sounding particularly harsh and lacking clean super-highs. I couldn’t understand why it was necessary to use some strange equalizing, until I was told there was a component miscalculation in the compression-driver passive protection network. Rather than a smooth rolloff, we had a substantial peak around 2 kHz in the passband.
“Also unbeknown to me, someone decided to remove all the super-high drivers, because they felt the new drivers would be adequate in that region,” he continues. “We had to fly a crew in to replace the networks, as well as put the super-highs back in. The new configuration is a substantial improvement over the old 2440 S-4. The super-highs disperse much more than what you’d think they would. They’re supposed to be very directional, but they seem to go everywhere! There ‘s a significant problem in the 1- to 5-kHz area with beaming and pattern control. Since air molecules absorb high frequencies in direct proportion to the increase of the distance the waves travel, a compromise must be reached between how many highs will be heard at the mixing position, versus their relative volume at the back of the room.”
The Clair S-4 is designed as a sort of universal cabinet, not specifically for long- or short- throw applications. Ideally, Jackson would have a special cabinet designed for long throw to the back of the hall. This, however, would probably require horn loading of the bass and mid-range, and a new compression driver horn, giving the cabinet an entirely different horn-type sound. Such a design would negate the advantage of the existing large array approach.
There are 56 cabinets for the house system, each weighing approximately 450 pounds. The boxes are supported by bumper bars built by Wilber Graybill in the Menonite-Amish region of Pennsylvania. Speakers are fastened to the bumper bars and to each other using straps manufactured to within a tolerance of half an inch. The entire configuration is raised above the stage using a combination of 20 one-ton (single-chain) and two-ton (double-chain) Columbus and McKinnon Loudstar hoists (Figure 2).
The S-4 speaker has a right and left configuration, one being the mirror of the other. This is to aid the coupling effect between cabinets and reduce the interference patterns which result when more than one speaker covering a given area is driven by the same coherent signal. Such interaction forms a dispersion pattern of peaks and valleys in the frequency response for both the horizontal and vertical planes. The magnitude of interference depends on the distances between the speakers and the wavelengths involved. Since interference varies with frequency, this effect is used to advantage in a radar phased-array antenna, where patterns of fixed antennas are fed with varying signals which interact to form a beam that can be swept electronically. In audio applications, however, the object is to minimize this effect by alternating left and right speaker cabinets.
“I’ve been trying an experiment on this tour,” Jackson notes, “which seems to be working out pretty well. We’re playing 360 degrees for the first time because Bruce [Springsteen] enjoyed the proximity of the 360-degree seating at the “No Nukes Show.” Having left/right stereo in a situation like this is ridiculous, since only the audience in the center can enjoy what the mixer is hearing. The rest hear a dubious stereo, which is fine for a group like Pink Floyd where a distant, etherial sound compliments the music.
:We decided we would give the people at least some stereo to take advantage of the extra dimension given to such instruments as the piano and organ,” he adds. “This was implemented by driving alternating vertical rows of speaker cabinets with the conventional left or right signal. Primarily, this practice serves to break up interference patterns. Neighboring cabinets are no longer driven with the same coherent signal, while also giving a subtle, pleasant stereo effect to everyone regardless of where they’re sitting.”
Stacking cabinets in a flat array causes interference problems, too. In fact, interference is so noticeable that movement by just one foot to the right or left while in the auditorium puts the listener in a different part of the pattern, and noticeably alters what is heard. To reduce this effect even more, speakers are hung in big arcs both horizontally and vertically. “There’s no particular degree of arcing — just determined by where the seats are, it changes with every set-up,” he says. “I do it by eye, by projection, and by what I know will spill down from the highs. It’s all by feel, really.”
Speakers are tested before every setup by doing a full frequency sweep and a pink noise test. “During the sweep, we listen for various traits of diaphragm rubbing loose dust caps and so forth,” Jackson explains. “For example, JBL had some bad luck with a run of glue on their speakers, and it caused the voice coil to separate from the diaphragm. That could be heard very clearly, but there are certain things you can’t hear as clearly as you’d like with the oscillator. When sweeping, it’s hard to find sources of trouble, because of the various interference patterns and effects that goon with a pure sine wave, which rarely happens in a practical situation anyway.”
The pink-noise test basically shows the operation of all the speakers and makes some problems more apparent. After a couple of weeks, a voice check is done on each box. That shows up more subtle changes, such as speaker wear and deterioration.
Amplification for the house system comprises Phase Linear 700 amps built to Clair Brothers’ specifications. The grounding and output stabilizing network was modified to make the output “electronically a little beefier,” and the chassis fabricated from steel rather than aluminum. According to Jackson, “The basic ‘Phase’ has a lame output network. If it goes, it makes the amp tend towards oscillation, which is compounded by the inter-amplifier capacitance of the long feeds we run up to the speakers. The long cable runs also reduce the damping factor by adding unwanted impedance to the amplifier.”
Clair Brothers used to hang the amplifier racks with the speakers, but if an amp or speaker blew during a show there was no way to re-patch it until after the performance. Instead, it was decided to run heavier (12-gauge) cable and keep the amplifiers on the ground.
There are 14 amplifier racks with four Phase Linear units in each. The top amp in the rack drives the highs in four cabinets (two cabinets per side); the second amp down the mids in four cabinets; and the third and bottom amp the bass (one cabinet per side). The two top amps are loaded to about 350 watts into 8 ohms per side, while the bass amps are rated at about 700 watts into 4 ohms per side. All amps are transformer isolated from the console.
A standard three-phase, Y-system (200-amp capability per leg) with a ground and neutral powers the show. Clair uses two power distribution panels, one on either side of the stage. Each panel has 12 twist-lock outlets powered by two legs, a ground and neutral. There is also a three-phase outlet to supply the Loadstar motors distribution panels, which requires only the ground — no neutral.
One of the theoretical advantages of using a three-phase, Y-system is that if the loads on each leg are equal, no current will travel down the neutral. Instead, the voltage rotates around the legs and balances out; unfortunately, this does not occur with the type of load Clair Brothers has to contend with. Power rectifiers in the amplifiers conduct current only at the top portion of every cycle. Such a phenomenon causes peaky, not sinusoidal current waveforms, which tend to cause very high neutral currents. If the main service transformer is not particularly large, or its distance from the amps is too great, there is substantial power line distortion, resulting in a flattening off of the tops of the incoming power sine waves. This reduces the maximum available power in the amplifiers.
“A lot of the problem is caused because we draw about 150 amps per leg,” says Jackson. “If the system ground is tied to the same point as the neutral at the power disconnect box, and the neutral is referenced through a long conductor, the large dirty currents flowing through the neutral line will pollute the ground and cause all sorts of noise in the system.”
In most cases, Jackson’s crew attaches to the cold water pipe for ground, but be cautious. Sometimes plastic sections will have been substituted for metal pipe, making the ground point invalid. If that’s the case, search for another ground source. If worse comes to worse, he recommends tieing to the box, but warns that the ground must be capable of handling the maximum fault current.
Stage Miking & Amplification
A common complaint from most groups playing in large arenas is the number of mikes, cords and stands that clutter the stage during a performance, as well as the confining nature of working with stationary mikes. The keynote of this tour has been to change all that – to obtain as much flexibility and as clean as looking stage as possible (Figure 3).
Meanwhile, Table 1 lists the on-stage microphones, effects, direct injects, and communications channels routed through a 40-way snake to the front-of-house mixing console (L.A. Sports Arena Concert, November 3, 1980).
As can be seen from the mike sheet, almost all vocal mikes are Audio-Technica ATM 41s. Springsteen’s mike is an Electro-Voice DS35, because it sounds much better with his voice. Jackson feels that “His vocal technique is great; he gives us all the level we need. He can run out in front of the PA stacks and still not feedback. Sometimes the proximity effects are a pain in the ass. I find I EQ out the proximity, depending on what song it is and how he’s singing it. Sometimes I’ll have to add some midrange punch.”
Springsteen’s mike channel is patched through a dbx Model 902 de-esser. dbx put together a rack especially for this show, containing the 902 de-esser and two compressors with the “over-easy curve.” (“The curve comes in much more gently,” Jackson offers. “It’s not as radical as the Model 160s.”) Also supplied in the rack were five noise gates – “which I’m playing around with to find the best spots to use them. They do a great job on the drums. I find the best method of gating the vocals is to ride the faders.”
Nady Systems of San Francisco had just put together an EV DS35 mike transmitter and receiver to be tried out in L.A. Jackson: “The fidelity and range are excellent. Bruce has to decide whether he wants a $3,000 mike to go out in the audience for one song. I much prefer he be directly coupled to the system most of the time. The radio mike does have companding circuits in there, and you can hear them if you really listen. But for an effect, the mike’s fine.”
Nady also brought in a radio system for Springsteen’s guitar, which everyone agreed sounded very good. “The previous one colored the sound. The new one seems to have licked all the problems. I’m very impressed with it, but I’d like to have him on a cord.”
Springsteen plays through two amplifiers that are both hidden from view beneath the drum riser. Each amp is miked with a Sennheiser 421, and either can be selected for the monitor or house mix. The sound from the Peavey amp is very bright, while that of the Fender Bassman is much gutsier. Jackson usually uses the Fender sound for the house, while Springsteen prefers the sound of the Peavey on stage.
Springsteen’s so active, a 100-foot guitar cord is used to allow that freedom of movement. Unfortunately, such a long cord tends to load down the guitar signal and roll off the high frequencies. Jackson has built an electronic impedance transformer into the guitar, which sends out a low-impedance signal (Figure 4).
“I had to steal the guitar away from Bruce to do the modification,” Jackson notes. “And then I thought I’d better put a switch in there, too, just in case he didn’t like the sound. Luckily he uses the low impedance setting all the time.”
The only guitar effects Springsteen uses are an MXR Distortion Plus and a Lexicon Prime Time. The Prime Time is used instead of an echo unit; the variable time base also approximates a 12 string effect by subtly shifting the pitch up and down. “The setting was tweaked quickly. It’s probably not ideal, but it works fine and eliminates having to keep a 12-string in tune.”
Since the Prime Time and MXR are located at the guitar amp, a relay was necessary to allow control of those pieces from the front of the stage. Jackson substituted a stereo jack at the output of the Distortion Plus — the tip is now the clean signal, and the ring the distortion. A relay in the Lexicon runs off its own 5-volt power supply. The control signal that runs through both boxes also powers the LEDs. Two switches on stage select between fuzz and clean sound, or Lexicon and normal sound. An LED above each switch alerts Springsteen as to whether the circuit is in or out (Figure 5).
Guitarist Steve Van Zandt also chooses between two amps (Mesa Boogie or Roland JC120), depending on the style and sound desired. He makes the choice himself on-stage, by way of a simple switching system. Both amps are miked with Sennheiser 421s, while all acoustics are taken directly through Countryman direct-injection boxes.
Bass guitar is also taken direct. “If the house system isn’t on,” Jackson explains, “Garry Tallent is lost; it doesn’t sound like he’s playing through anything.” Tallent’s Acoustic 320 and three bottoms located on stage have very little power relative to the house system; they ‘re primarily there to let him hear some of the highs on stage. The bass is kept out of the monitor mix to avoid muddiness and leakage problems.
The bane of all sax players is to be forced to stay in front of a microphone in order to be heard. Charles Gerber (a previous sound tech for the E Street Band) devised a small clip that attaches to the bell of the horn, and shock mounts a mike just outside the bell. The only shock noise it picks up is the actual noise of the instrument itself, which is minimal when compared to the freedom of movement it allows saxophonist Clarence Clemons. Both the tenor and baritone are miked in this way. The soprano. which is only used for one song, is played into the percussion mike mounted on Clemon’s mike stand.
A special Helpinstill arrangement is attached to the Yamaha grand, comprising two pickups. One is mounted underneath the strings near the hammers’ contact points, giving somewhat of a bright sound. The pickup is actually bolted into the frame of the piano and extends across the entire sounding board — although not continuously in one long piece (Figure 6). The second Helpinstill is mounted on top of the strings, and more towards the middle. If the pickups are panned left and right (top-left, bottom-right, rather than left piano and right piano), a very fat stereo effect is obtained.
The Helpinstill box looks standard but is in fact an active device. It has six high input impedance gain stages that feed the pots to adjust individual levels of the two pickups. An active combining network has a frequency tailoring circuit around it to give the piano its characteristic brightness.
“Roy [Bittan] is usually left-hand heavy anyway,” Jackson says. “He plays to what he hears in his monitors, and they don’ t have a lot of low end. We talked about it once and he reacted the other way — right-hand heavy. He lightened up a little too much, but the piano is definitely brightened towards the high end. If I have it too fat, it tends to muddy things up when things start rocking. I try to find a happy area that works for both medium and loud levels. I do find myself boosting the low end when he’s playing by himself. Basically, he acts as a glue to hold everything together, because he’s usually pretty consistent and not too harsh.”
The Yamaha CS 80 synthesizer is another instrument used only on one song and is lifted on to stage when needed. It’s taken direct via a Countryman box and fattened up through a Prime Time. Roy Bittan has a volume pedal on the CS 80, which can cause problems.
“It’s a situation where we’re still working that out,” confides Jackson. “He’s building and at the same time I’m pulling him back. He’s building faster than the song requires it, probably as a result of what he hears in his monitors. If I let him build up at that rate, it would be the ‘Bruce Springsteen Synthesizer Band’. Early on the tour, the organ player would keep time with his volume pedal. That drove me crazy!”
The Farfisa Combo Compact, Acetone Top 5 and Accordian electric pianos are all taken direct for the house and run through a Lab L-5 amplifier for stage sound. The rare, keyboard operated glockenspiel was rebuilt inside of a box to isolate it, and is miked with a Countryman EM101, an amazingly flat electret condenser mike. The Hammond B-3 is coupled to two Leslies for on-stage sound.
“Danny [Federici] has special drivers on the horns and they’re powered by two Phase 700 amplifiers,” Jackson adds. “Trying to mike them at that level compounds the problems of miking a Leslie in a live situation. Standard Leslies at standard volumes are much easier to put across through a PA.”
He had a special baffle box built for a third Leslie, which is kept underneath the stage in a huge flight case (Figure 7). The box is stereo miked on top, double miked on the bottom, and runs at a lower volume to feed the house system. The standard Leslie power amp is placed in the back side of the baffle along with XLRs for easy connection to the mikes inside.
Drums are always the toughest instruments to mike. Leakage and lack of tone control are the chief problems, along with aesthetic concerns after the kit has been buried beneath an avalanche of mikes and stands. Jackson is striving for a clean “bar band”-look for the drum kit, as well as a present, out-front sound. The first step was to have aircraft welder Bill Carter, from Lititz, PA build a custom frame out of aircraft-grade tubular steel (Figure 8). The bass drum and floor tom fit against the frame, eliminating the common problem of their sliding across the riser.
The snare and high-hat stands are fastened to the frame to allow quick and easy setup, as well as holding them in place while playing. All mikes have their own quick-re lease mounts built right on to the frame, thereby allowing mike placement to be consistent from set-up to setup. Three mikes are regularly put on the snare: two on top, and one on the bottom. Usually, the EM101 inside and the Shure SM81 on top are chosen to be blended for a room sound; however, any combination is possible depending on the conditions and the particular requirements of any given hall.
The Countryman EM101’s compact size allows the mike to be fastened to the inside of the snare shell, but well away from the air hole, thereby preventing any of the wind noise rushing through the opening. Only the mike cord is run near and through the hole.
The Shure SM81 condenser mike has been modified by adding another capacitor in the head. The standard internal value of this capacitor is not sufficient to keep the mike from overloading. Therefore, an additional capacitor parallel with it creates a 25 dB pad, as opposed to the normal 10 dB pad.
Pre-tour rehearsals were carried out at Clair Brothers’ facilities in Pennsylvania, a large rehearsal studio with a sound room isolated from the main room — very similar to a recording studio — and with sufficient space to hang all the lighting equipment in order to work out any potential rough spots before hitting the road. Such sound checks foretold leakage problems into the drum mikes from the monitors positioned on either side of Max Weinberg’s seat. Sonex foam was fastened to the drum side of the monitors and extended about three to five inches above them, to baffle the speakers output away from the microphones. Although not perfect, it was a very efficient cure.
Jackson has several ideas he feels may remedy such problems as isolation and the presence of too many obviously visible mikes. He’s experimented with guitar pick-ups on the snares, and “the results were great.” He’s also taped guitar strings to the heads of drums, and then placed pick-ups over them. It gives a solid, punchy sound that can work well for the monitors, where the object is to get the volume as loud as possible without feedback. The overall quality, however, is not totally accurate in terms of an exact drum sound. At the present time, two EM101s are used on the toms to get enough gain for the monitor feed.
“I have some Barcus Berry pickups that I’m going to try on the cymbals,” Jackson continues. “I’ll use that signal to gate the actual microphones which will be moved from underneath to above the cymbals, where I think they’ll get less leakage. The mikes underneath the cymbals get so much leakage from everything else — drums and monitors — that I can’t use the cymbals as much as I’d like to, and I have to ride them a lot. My two choices are the EM101, which is unfortunately omni-directional and picks up from everywhere, or the AKG 451 that offers the feature of a head that can swivel from the body. I’d like to mount the guts of the 451 underneath the cymbal in the cymbal stand and run a coaxial tube up and over to the basic diaphragm section — which is available as a stock item — mounted above two cymbals.
“The main problem is the tube being sensitive to all the bashing around. It’s a matter of isolation, and I’m not quite sure at this point what I’ll do. But such a placement would allow the shape of the cymbal to isolate the mike from the monitors and other drums. Right now the monitors reflect off the cymbals into the mikes and it’s a tradeoff: Do I want more cymbals at the expense of ruining the sound of the snare, high-hat, and toms?”
Next time, we’ll present the approach for monitors with this show. — Editor