The Grateful Dead's "Wall of Sound".*

Irony: after helping develop the WOS, Healy found himself out of a job, as did Betty (both only temporarily, of course). Kidd Candelario did the taping and mixing for it during the WOS period.

 

This is, of course, in contrast to a great many other "employees" who continued to draw paychecks for the flimsiest of reasons, forcing the band to continue touring through Jerry's ill health to support the machine.

As an example, I myself saw Stanley Mouse receive a check for literally just showing up at the photo shoot for "Built to Last " - I believe he got a credit for it too.

 

Nice picture of a happy Bear.

 

I think the Dead had 2 Nagras by 1976; many of the Betty Boards avoided missing pieces from reel changes in this way. I'm pretty sure the first time a Nagra was used was the AOM '72 shows.

 

One of the many WOS items that has always bugged me is never getting a great explanation for what the Summing Amp in this diagram actually did.


I think when you hear descriptions that the vocals were mixed to the vocal cluster, you tend to always think there was a console involved, or in those days their tube Ampex MX-10 mixers. Well some research and a few well placed questions has now confirmed that the Summing Amp designed by John Curl-- then at Alembic working with Wickersham-- and built by Mark Levinson, did a) the phase cancelling for each of the differential mics, b) was a resistive mixer, mixing all of the mic channels to mono, and c) was a line driver to pass that signal to the crossovers and then either the McIntosh MC 2300 300W per channel solid state amps, or for vocal and drum systems, one MC 3500 350W mono tube amp each to power their tweeters.

So in the final analysis, and clearer to me anyway if it already should have been, the vocal "mixes" were in fact 100% controlled by the band through the sensitivity knobs on the mics, and whatever levels they chose got mixed within the summing amp circuitry. I came across a sentence somewhere that members of the crew would walk around the audience and give feedback on the mix, but as far as the equipment doing the mixing goes, the one aspect that needed to be combined, the vocals (I also think multiple pianos were also mixed but I assume the same method), no mixing knobs or mixing crew necessary, just the summing amp's circuits. What these summing amps did always passed me by because a) I always expected knobs and a console to do the vocal mixing, and b) because I cannot read circuit schematics; if you can read schematics, see page 25-27 of this http://www.americanradiohistory.com/Archive-DB-Magazine/70s/DB-1976-04.pdf

Here is the JC-ULD module specially made for the WOS and was +/- 24V and could drive 600 ohms easy.



Now after all of this I am still guessing somewhat, because only so many questions get answered, but I imagine this summing amp is pretty small, and since it is a line driver as well, it is likely sits at the wrong end of a cable needing to get to a crossover/amp. So is there any chance one of the small boxes at the bottom of that center mic stand is the summing amp? The Shadow knows!


www.kirkwestphotography.com

 

Levinson ran with that John Curl module design first, and the JC-2 preamp became a hit.




That design carried through in Curl’s Halo JC-1 onward and in the CTC Blowtorch preamp.

 

Don't forget Curl's Vendetta pre-amp, still held by some to be the best phone preamp ever, or at least the best solid-state one.

 

Whoa, what a hidden hi-fi connection that at least I sure didn't know about!

 

Ned anecdote from the '74 Hollywood Bowl WOS show:

"That show, was… every show was intense in some way or other. That show was particularly intense because I had my Fender 88; it was delivered to the stage early that afternoon; Bill Graham was there supervising, and the forklift dropped the Fender 88 onto the Hollywood Bowl stage, and it was a mess, and Bill Graham’s promise to me was that by the time we performed that night he would have another Fender 88, which was a rare instrument at that point in time, on stage for me, and Bill came through, and it was there."

 

Just to keep this thread rolling, I remember reading online the on-stage volume was somewhere north of 120 db, which certainly puts them in the conversation of 'loudest band ever,' as pointless a distinction as that may be. And yet we have comments from attendees on this thread that it wasn't all that loud. The Wickersham article from 1976 talks about 110 db being an audience level, still pretty loud.

 

Wow..

 

Two words; dynamic range. Unlike all other bands from that era, and still many or most from the current one, the Wall of Sound didn't compress the sound. That's typically done at the PA mixing board, something the WOS didn't have. So peak levels of 120 dB probably corresponded to a typical average RMS value closer to 95-100 dB, which is not that loud. Compare that to a typical loud rock band with peak levels of 112-115 dB and average RMS close to 110 dB. Add in the low distortion, and the fact that the sound carried better (line source rather than point source) and it all becomes much clearer.

 

For that matter, I wouldn't be surprised if peak levels at the audience rail (probably where the sound was loudest from the WOS) significantly exceeded 120 dB.

 

Dumb question, but how did the WOS "free up" seating space? Does that mean, despite its formidable height, the WOS actually had a smaller footprint than most other systems at the time? Or did the greater power requirement of "more conventional systems" impact seating?

 

@bmoregnr - how about JRMs question above?

Or here:

 

It is fun to be back on this thread again, sorry I missed that question @JRM Of course this is best answered by those who were there; by my days they were already flying the PA, but I have to guess the amount of space saved on each side of the stage made the difference. I would expect previous to that '73 Boston Music Hall show, perhaps 60-70% of the amount of the WOS PA footprint was placed at each side of the stage. Now that might not have taken up 400 seats itself, but if you consider a band of seats from floor upwards times two who couldn't see the stage because of the PA at the sides, I could see that being 400 seats.

So with the whole PA as a wall behind the stage those side sight lines open up. In my day plenty of people paid good money to sit behind the stage or with obstructed views; but my guess is in '74 you didn't or couldn't sell those seats, so the WOS didn't hurt in that regard.

 

Just a bunch of great Rick Turner WOS quotes. I love reading Rick Turner talk about what he did; these guys were improvising on a level pretty on par with the music.

"I went back to the old thread about the Wall of Sound and I saw that the Bose engineers missed a few of our tricks.

In fact, the vocals were launched by a four way system that had one column of 15s about 36 feet tall crossed over at (OK this was a few years ago!) about 250, then it went to the curved front array of 12s up to about 2 K, then to the curve front array of 5s, and finally to that single row of EV T350s for 5 k on up. So we were stepping down the vertical height of the arrays as the frequencies went up. The goal was to achieve even dispersion in both horizontal and vertical planes of all frequencies...given the reality of what drivers were available and the fact that at that time...1973, there were no horns that didn't have really objectionable throat distortion. That's the non-linearity of compressing and rarefacting air in the tight environs of a horn driver throat. It wasn't until John Meyer figured out how to cancel throat distortion that that problem was solved. Anyway, we liked the low distortion sound of cone drivers and uset them up to 5 K in arrays that did follow the classic frequency/line array formulae. Hey, we actually knew what we were doing!

My own role, aside from just being there with a trained set of ears, having toured and mixed front of house for them, and being respected for that, was that I came up with the 1/3 octave wave length formula for cabinet dimensions for the sealed boxes for the JBL drivers. The idea was to spread any standing waves in the boxes 1/3 of an octave apart...and to then damp the innards of the boxes with horsehair carpet padding.

BTW, there was no PA mixing console. Each mic had a volume control on it. In the first version, there were no monitor speakers; the band heard what the audience heard. And I've never heard a big system that sounded better...to this day. Closest in a big system is the newer JBL line array systems I heard at MerleFest last Spring.
So for small and medium sized gigs, I have a lot of respect for what these guys are doing here at Bose. Good show!"

"When I worked up a lot of the Wall of Sound speaker cabinet dimensions, I used the cube root of 2 (1.25992105) as the multiplier to determine the ratio of depth to width to height of the cabinets. Take your smallest dimension and multiply it by that, then take that result and multiply it again by that constant. The idea (for better or worse...) was to spread any standing waves out equal distant from one another in the audio spectrum. There are other formulae that some folks use...Golden Mean, etc.

We also used heavy rug padding with horse hair in it to damp internal reflections.

We went with closed boxes because the transient response is better than with bass reflex designs, and the deep low end extension is better way down there, though they start rolling off a bit sooner than the bass reflex. But then when stacked in the tall array, that low end comes off better because it's better directed.

Bear did the design of the big curved arrays."

"There was probably some comb filtering, but there were no acceptable alternatives at that point in time. Horns all suffered from throat compression distortion...it was John Meyer who finally figured out how to deal with that. We preferred the sound of cone drivers all the way up to the top where we used the EV T-350s driven by tube amps...the Mac 350s. The cones of the 12s and 5s were so tightly packed together that they really did tend to act as driver masses.

Bear in mind (pun intended) that we were doing the best we could with what was commercially available at that moment in time, and it was damned good. I've still never heard a system that comes close to what the WOS could do on a good day. The use of line arrays that were based on actual wave length theory really worked. Many modern line arrays ignore that whole thing...stepping down the height of the columns as frequencies go up...and too many are done with nearly full frequency cabinets with mid and high frequency horns in each cabinet. Now that will give you some comb filtration! And you cannot really project good controlled low end without going to at least a 30 foot tall line array. The way most subs are used is utterly wrong; they are effectively point sources splattering low end all over the venue and making everything sound muddled.

All frequencies can be directed if you pay attention to wave lengths and the size of arrays. The idea that lows are inherently non-directional is rubbish. Dispersion from a source is completely wave length dependent...until you get into some of the sonic holography technology, and that's just not practical yet in concert settings."

"Line array dispersion theory is based on the wavelengths produced, and wavelengths are pretty much an absolute on this planet. A rule of thumb...a convenient one...is to just estimate the speed of sound at sea level at 1,200 feet per second. Yes, I know it's a little bit slower, but for in your head math, 1,200 is a decent figure. That being the case, a 40 Hz tone has a wavelength of 30 feet. Ain't no way you're going to change that. So, sure, you can use shorter arrays, but you won't get the same kind of dispersion control in the critical vertical dimension. That's what pumps the low end into the audience and minimizes the splatter on the ceiling and behind which just muddies everything up. It's just math, not myth. No voodoo involved."

https://www.bosepro.community/g/portable/topic/anyone-remember-the-wall-of-sound

Grateful Dead Music Forum • View topic - Original Wall of Sound speaker formula...

 

Just to clarify the amplification -- several reports of setups from back in the day --

Several setups have been reported for The Wall of Sound:

1. 89 300-watt McIntosh solid-state and three McIntosh 350-watt vacuum tube amplifiers generating a total of 26,400 watts of audio power. 604 speakers total. [1]
2. 586 JBL speakers and 54 Electrovoice tweeters powered by 48 McIntosh MC-2300 Amps (48 X 600 = 28,800 Watts of continuous (RMS) power).

I inserted the words McIntosh which are underlined. I need to check my McIntosh hardbound to see if there is anything else -- don't have it with me at the moment.

Best sirs,

Boib

 

The table at the top of page 28 at the link below has yet another configuration, 46: 300W SS and 2: 350W tube driving 641 speakers. I think the 600W vs. 300W difference would be the same amp but just run in mono which they did. I am surprised to see 89 amps mentioned, maybe that is a typo?

I have exchanged a few emails with questions for Rick Turner in the past and the first thing he always says is there were many variations, it was always evolving, so you can’t really talk about it as a static thing. It would be interesting maybe to see what the differences were over time but for example it is hard to know what version Wickersham is discussing in this article, although given it is a ’76 article maybe that is where they ended up in October ’74. http://www.americanradiohistory.com/Archive-DB-Magazine/70s/DB-1976-04.pdf

 

Was lucky enough to see the Dead at Dillon Stadium in Hartford Connecticut. I believe it was July 30, 1974, about a month before my 17th bday. We were able to get pretty close to the stage...perhaps 30 to 40 feet away. It was an awesome and long show. The wall of sound was massive, sounded great and looked very similar to the photo in post 112. The band put on a good show.... Jerry seemed in a good mood as it was only a day or two before his bday. I believe they opened with Scarlet Begonias ... Mars Hotel was released that summer. Ahh....good times!

 

July 31 1974

Dave's Picks Volume 2 - Wikipedia

www.archive.org/details/gd1974-07-31.sbd.miller.32353.sbeok.flac16

 

Yep, that's the one ... I was off a day on the date.

Thanks for posting this! I see you're from CT as well....were you at the show?

 

Tons of good photos here, you might even find yourself in one! Grateful Dead 1974 07-31 | Dillon Stadium Hartford CT - Images | James R Anderson Photography

Not sure where this is but cool pic nonetheless

 

Haha, no, that was more than 20 years before my first GD show.