The Grateful Dead’s “Wall Of Sound”

In March of 1974, the Grateful Dead unveiled a sound system unlike any that had ever been, or that the world has seen (heard) since. It was designed by audio engineer Owlsley “Bear” Stanley, who had recently been released from prison, and at the time was the largest portable (somewhat) PA ever. The main component of the system was a huge wall of speakers erected upstage, behind the band. This mountain of speakers became known as the “wall of sound”. The system was unique due to its size, (it is reported as consisting of around 600 speakers, weighing 75 tons, and requiring 26,000-28,000 watts of continuous power, depending on the current point in its evolution) as well as its functionality and quality.

The system was actually six individual PA systems operating independently but together. There was a separate system for vocals, lead guitar, rhythm guitar, bass, drums, and piano. Each had its own set of amps, processing, and speakers. Band members had control of the area of the wall that was providing reinforcement for their particular instrument, as well as the levels of their vocals. A main (or monitor) mixing console was not required for the operation of “the wall”.

The challenges associated with such a set-up are obvious, the least of which not being the requirements for transportation and installation of this behemoth. The time it took to load in made it necessary for the band to tour with three complete packages and leapfrog much in the way that a broadway show would send gear in advance. There were over 20 crew members responsible for putting it all together, with assistance from local labor (much of which was provided by members of the Hell’s Angels motorcycle club, which added an interesting dynamic).

This was actually the band’s second attempt at creating such a complex audio arrangement. The first experiment came about a year earlier and was met with tragic results. Every tweeter blew as the band began their first number.

The installation process would begin with the construction of a large scaffolding rig on the downstage side of where the speaker wall was to be erected. As the wall grew, block-and-falls were employed to hoist speakers, which were essentially wooden boxes affixed with speaker cones, up to the higher levels. The speakers were tied to the hoists with rope, raised up and landed on top of the last level. There were also chain motors that were used to lift some of the more obnoxiously massive parts, such as the cylindrically shaped structure of cones that was the section of the wall which provided reinforcement of high and mid-range vocals.

I imagine this was probably some of the oddest seeming stage work to ever take place. A bunch of gangsters building something equivalent to the pyramids while dogs and small children run around on stage. There was even some occasional breast-feeding.

Conventionally, main speaker arrays are located in the downstage corners of the stage, either flown or ground-based. Monitors are used to direct sound back towards the band but, although configured to the performers’ preferences, it sounds nothing like what the audience is hearing. The upstage location of the wall allows the band to hear exactly the same thing that the audience hears, but it also makes the avoidance of feedback somewhat tricky.

What happens, typically, is sound enters a microphone, is amplified and pushed out a speaker, goes back into the mic and this loop pattern creates some of the most awful noise known to human ears. Several steps were needed to prevent this phenomenon from ruining the effectiveness of the whole system.

First of all, the gargantuan cylindrical structure which brought the higher end of the vocals was placed at the top. It produced more horizontal than verticle dispersion, so they could keep most of the sound out of the mics. The low end speakers were arranged in columns lower in the wall and were less likely to cause feedback. Regardless of the physical separation of all the speakers in the vocal system, it was designed in a way to allow all frequencies to be heard equally well. That’s what they say.

In addition to just putting the speakers up high, more technical efforts were needed in order to further minimize the presence of feedback. The vocal mics were actually matched pairs of condenser mics run “out of phase”. The mics were arranged one on top of the other a few inches apart. (60 mm, actually. Not sure if that matters). The band members would sing into the top one, and the sound from this would be amplified like normal. The mics in reverse phase would combine signals in a “differential summing amp” (don’t ask) and cause all sound common to both mics to cancel each other out, thus eliminating feedback from the overall mix. That was hard.

The parts of the system associated with the instruments were slightly less complicated. Each had its own system of amps and crossovers, which would send different frequncies to different parts of the wall, but one of the more interesting aspects of the instrumental amplification was how Phil Lesh’s bass was integrated into the system.

The bass was reproduced quadrophonicaly, which is like stereo times two. Instead of just a left and a right there were actually 4 sound “areas”. Coincidentaly, there are four strings on the bass. It was configured so that each string was on its own channel, and the signal from each was bussed through its own system of amplification and projected from its own group of speakers. Each string came out of a different place in the wall.

The kick drum used its own amplification channel and a column of sixteen 15 inch speakers. That’s sixteen 15 inch speakers, all kick drum. It doesn’t necessarily mean it’s loud, although it can be. It was more about having head room. If all the speakers aren’t being pushed to their capacity the resulting sound is going to be much cleaner.

Amplification of all the instruments and vocals was acheived in a manner in which each speaker was dedicated to a small portion of the entire sound output.
This resulted in an impeccably clean sound, almost entirely free of intermodulation distortion. In conventional speaker arrangements, sounds of different qualities and frequencies compete with each other as they cause speaker cones to behave differently than if they were just producing one type of sound. So a sound system could produce as much volume as this one with the use of much less power, but it would be inferior in overall quality and lack the ability to retain clarity in distances of up to a half mile, or be as cool, as this one.

The wall of sound can be seen in the documentary/concert film The Greatful Dead Movie. It was filmed during a 5 night run at San Francisco’s Winterland Ballroom and contains concert footage as well as accounts of the technical aspects of the Dead’s live performance. It’s the third greatest rock and roll movie of all time, right behind “This Is Spinal Tap” and The Band’s The Last Waltz, which, perhaps not coincidentaly, was also filmed at Winterland.

There is a production credit for IA 16 which rolls by as time lapse footage reveals the deconstruction of the scaff. (Man those guys are fast). I wouldn’t assume that too many of the Hell’s Angels are cardholders, but there’s some representation happening. Probably working under a CBA.

This sit-down in San Francisco marked the end of the road, litteraly, for this mighty wall. The rising costs of fuel and logistical headaches forced the band to abandon this expirement after about 50 shows in six months. It also turned out that the Angels didn’t exactly create a peaceful work environment. These factors also led the band to decide to “retire” themselves. They only played a handful of shows in 1975 and didn’t really start touring again, with a more conventional sound system from here on out, until the middle of 1976. The band would remain whole (relatively) for another twenty years until all the things caught up with Jerry in 1995. (Crying a little right now).

A lot of this might seem pretty complicated, but remember, it was really just some dudes (and one chic) smoking a bunch of weed and screwing around every night.

Rigging Primer

IATSE 205 ETCP RIGGING STUDY RESOURCES

BY JOE MARTIN

DISCLAIMER

THE RESOURCES AND TIPS GIVEN IN THIS GUIDE ARE NOT ENDORSED BY ETCP OR ANY ORGANIZATIONS RELATED. THIS IS MERELY A GUIDE TO FIND INFORMATION AND REINFORCE INFORMATION THAT IS RELATED TO STAGE RIGGING AND COVERS KNOWLEDGE THAT WILL BE USEFUL IN TAKING THE EXAM.  UNDER NO CIRCUMSTANCES USE THIS KNOWLEDGE WITHOUT PROPER EXPERIENCE AND TRAINING. JOE MARTIN AND IATSE ARE NOT AFFILIATED WITH ANY OF THE MANUFACTURERS LISTED. ALL MANUFACTURER LINKS ARE FOR THEIR SUPERIOR INFORMATION AND REPRESENT INDUSTRY STANDARDS. THIS DOCUMENT WILL NOT BE PUBLISHED OR DISTRIBUTED OUTSIDE OF IATSE UNLESS PERMITTED.

FORWARD

Hello Brothers and Sisters of the 205! I have created this guide in hopes that all in our local who want to pass the ETCP Theater and Arena Rigging exams have the resources necessary to pass with flying colors.  As someone who is a certified Theater Rigger, I have taken the exam and know what it takes to acquire the title. While individual study is necessary, the essential key to success is group study. Throughout the year, I will be holding study sessions for everyone who is interested in testing for the certification. These sessions will be mostly on the math aspects of the test, as most experienced riggers can already pass the general knowledge portions. Those with an interest in rigging but not the test should attend the Beginner Rigging Class, as everyone in the field deals with rigging on a daily basis. I encourage everyone to dig deep into the knowledge pool of rigging. The principles that we use in stage rigging apply to many other trades, and will serve you well in your career. Much of it comes straight from high steel ironwork and ship/crane rigging. In your studies, it is also important to brush up your knowledge of mathematical and general physics. Everything we do as riggers is directly related to the properties of gravity and geometry/trigonometry. A solid background in these subjects will be a big help. I wish everyone success in their journey, and I am always here to help! If you have any questions, please contact me here.

RIGGING PRACTICE, TERMINOLOGY, AND MATHEMATICS

Unfortunately, the information that needs to be given in this section can not be pulled from a website. That used to be the case, but some of the authors listed below figured out that this information is valuable, and should be compensated for their time and effort in compiling it. While I know the books are pricey, they are the definitive texts in the field. Any serious rigger with intensions of moving on up in the entertainment world needs this information. You will have it for life. The texts here should be studied more than anything above. The respective books on Arena and Theater are mostly what the ETCP test is written from, and have the most official  information on the subject to date.  The math book by Delbert Hall is a fantastic addition to your arsenal. While Arena Rigging and Stage Rigging Handbook: 3rd Edition explain the math, Delbert teaches it in a way that doesn’t blow most humans minds. The book is totally optional, but will help immensely.  When the book was a website a few years ago, I used it to study and I would have been much worse off without it.

Stage Rigging Handbook: 3rd Edition -For Theater test takers

Harry Donovan’s Arena Rigging – For Arena test takers

Rigging Math Made Simple – All disciplines

Continue for links containing detailed manufacturer information on rigging materials.

COMMON RIGGING MATERIALS

Here are links to many of the major manufacturers that provide rigging hardware for the entertainment industry. The information you are looking for are the material data that specifies weight capacity, tolerances, and acceptable uses. Arena applicants should pay special attention to shackle, chain motor, and wire rope specifications, while Theater applicants need to pay special attention to hardware used in a counterweight system (i.e. batten clamps, tracks, hand line, 1⁄4” wire rope, trim chain, loft blocks, head blocks, and SCH40 1 1⁄2 pipe)

Types of Shackles:

This page shows what types of shackles you might encounter out in the field. Anchor shackles are what we most commonly use, you will likely never see chain shackles out in the entertainment world outside of special circumstances. If you do see a chain shackle, remember they are only to be used with one rigging attachment. A bridle hung from a chain shackle will place a side load on the straight vertical members causing an unsafe situation. Remember that an anchor shackle can only be used in a bridle if the bridle angle is more than 30 degrees. Anything less will be considered a side load on the shackle. For example, when we do low-low bridles at the Erwin center, we use a pear ring to make the apex of the bridle to prevent side loading of the hardware.

Master/Pear rings:

Make sure you scroll all the way on this page. It covers a variety of hardware from different manufacturers you will see in the field. As described above, this is the hardware you need to use for any bridle over 30 degrees or when there are more than 2 rigging attachments in the shackles bell. While it is not recommended you do so, sometimes the only way to get a point where you need it is through the utilization of this hardware. As long as you are using a Master/Pear ring that is rated at least 5:1 the tension you are placing on the bridle, all is well.

Wire Rope/Eye Bolts/Chain/Hooks/Turnbuckles/Swages/Clips/Thimbles/Snatch blocks:

Here is one of the greatest resources I have ever found on the subject of wire rope. Contained is not only strength ratings of many different types, but explanations of the reasoning behind structural design with wire rope as well as most everything it attaches to. Not only does it give the raw info, it lays out theory behind safe usage. All disciplines of rigging should study this well.

This page lists many of the common ropes used in counterweight and hemp systems today. Multiline II is the most common, you can see it in use at the Long Center. Stage Set X is also a variety you see in the McCullough Theater at UT. Other ropes listed on this page are much less commonly seen, but it is nice to know of their existence and material properties in case you are ever faced with a project that requires rope with a special application. These ropes come from manufacturer New England Ropes, which has been the standard in quality for entertainment industry rope needs. Most theaters you go into with a counterweight system will likely have New England Ropes, which is handy to know when ordering replacement line. When it comes down to your personal hauling line, generally any polybraid or polyester rope between 1⁄2” and 5/8” diameter with over 2000lbs tensile strength will get the job done. Your rope needs to pull through a pulley easily, and provide a good gripping surface without being hard on your hands. Do not purchase rope from a big box hardware store however temping it may be. The rope sold there is mass produced in China and does not come with an official tensile breaking strength or material data sheet. Make sure the rope you are buying is rated and batch tested. You can find rope for the same price as Home Depot through Rose Brand that is solid core polybraid and carries an official rating. Even cheaper if you buy a spool, which I highly recommend. (Custom colors!)

Track Hardware/Counterweight Hardware and Operation/Pipe Attachments:

H&H Specialties has a veritable gold mine of information on these subjects in their catalogs. Diagrams, rules of use, in depth explanation of track weight capacities and hanger spacing are all here. The PDF on Counterweight Rigging isn’t very exiting visually, but is a fantastic guide for the beginner, and a great refresh for the experienced. Spend some time here.

Steel/Pipe:

Check out this website to look up information on common steel material you will rig on in theaters and arenas. As a rigger, it is useful to know more than the average bear about building structure and the materials that comprise your theater/arena specifically. Always consult the building engineer in regards to the actual strength of the beams. Every building is different. In no way should the tensile strength of any material be used as a means of rating a system.

Fantastic article about chain grading and the reasoning behind chain grading. It even gives you the formula for calculating tensile strength of chain. As long as you know the size and grade, you can calculate the strength rating of any chain. Also provides links to spec sheets for every grade of chain. Note that anything under Grade 80 is not suitable for overhead lifting. Example of deck chain used in Arena rigging.

Chain Motors:

 Here you have the bread and butter of the entertainment rigging industry, the classic CM Lodestar motor series. Most road shows and rental houses will have a small army of these in varying lifting capacities. It is essential to know chain weights and motor weights to calculate your lifts. On the page, you can find the official maintenance manual for Lodestar series motors. Study this to get a really in-depth look at chain hoists, their parts, and troubleshooting. You will know much more than the average rigger. Most of the info you need to pay attention to for the tests purposes are the lifting capacities, electrical/control properties, and knowing that chain motors are rated 25% under their actual capacity to account for the small shock load produced by the initial inertia of lifting/lowering. Also note that Lodestars are rated in metric tons. Make sure to check out all the different models CM offers too. ProStars are popular for their light weight and silent operation, and are rated from 300-1000lbs, differing from the metric rated Lodestars. Make sure to note this difference when you look at the label on the butt of the motor housing.

Beam Clamps:

You will use beam clamps whenever beam clearance is too low to use traditional 5’ wire rope slings and still achieve trim height. Note that beam clamps of large capacities will not allow you to attach to steel too small to take the load it is rated for. In other words, if your rig is going into a building with 2” angle trussing (typical in small ballrooms and venues), you won’t be able to rig your show with your 1 ton beam clamps. Better hope your points are rated for less than a half ton!

Concluded: USITT 2014 Winter Symposium

USITT Winter Symposium will be January 17th-19th.

The coordinator, Rusty Cloyes, has given Local 205 a 3 hour time slot on Saturday, January 18th, starting at 1pm to give a presentation. Ben Adams from the IATSE Education Department will come and give the Union presentation to college students (about an hour of the time) and then 205 will cover the rest of the time. Things to be covered: A brief overview of how to get work with the union here, what is expected and safety issues. If you would like to help teach the class please contact sister Michelle Ferrier at isou@aol.com

From Sister Ferrier:

“Finally – any of us that are not working during the event (USITT) have been invited to register, pay the fee and attend any of the sessions. Preregistration fee is $60 (this includes the $5 USITT Membership fee). ”
http://southwest.usitt.org/symposium.html

**A couple of notes:
The 2014 USITT Conference & Stage Expo will be held in Ft. Worth this year. Member registration is cheaper than non-member registration.
USITT membership cost for an individual is $108, $162 for a professional. If you can or are able attend any of the Winter Symposium here, the $60 registration fee is a substantial discount.

USITT Winter Symposium 2014
USITT Winter Symposium 2014 Flyer

Concluded: Basic Fly Rail Class at The Long Center

From Jim Larkin, Director of Production at the Long Center:

All – we have identified the afternoon of Thursday December 26 as the next time to have a Basic Fly Rail Class, beginning at 12noon and lasting approximately 4 hours. The Advanced Class and qualifying tests of individuals will occur on Monday, December 30th from 9am to 6pm. Classes and exams will be held on the Meredith Stage of Dell Hall.

There is no limit to the number of participants for the class, but we would like to know how many students plan to attend, so that we can have the appropriate amount of pastries and coffee. The time required for the qualifying exam is dependent upon the number of candidates electing to take the exam.

The Basic Rail Class is a prerequisite for the Advanced Fly Rail Class. The Basic Class covers the environment of fly rail and loading rail, establishes standards of communication, and qualifies individuals to operate balanced loads that have already been installed on the system. The Advanced Rail Class provides instruction and qualification on the operation of the rail with unbalanced loads during a load in/out. Both the Basic and the Advanced classes are required prior to taking the test that fully qualifies an individual as an approved fly rail operator at The Long Center.

Please confirm participation with Frank Cortez. Email only; no phone calls please.

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