Can anyone throw light on the vocal mics used in the Grateful Dead’s 1974 concert video linked below ? It looks like a pair of interference tubes linked to a bespoke summing box…or a very early dual vape pipe/mic prototype ?

Also on view, with horrifying relaxed OHS rigging practices, is their legendary Wall of Sound speaker system.

All in all, well worth a look…times have certainly changed !

https://youtu.be/JOciFuV2APg?si=r2DCqi8xZbiAv5w6

They were matched pairs of B&K mics. They were wired 180° out of phase from each other to mitigate feedback. They used B&K because they had the best matched capsules at the time and they had to be as precisely matched as possible in order to work.

Thanks jheath...so I'm guessing that the out of phase pickup for ambient sound would negate feedback from the massive speaker stacks immediately above/behind the band (there were no monitor wedges...the band used the PA sound as their foldback monitors).

A singer would therefore use the upper mic capsule, to create a volume/phase differential which allowed their mic to be heard ? It seemed to work reasonably well, with the incorporation of small foam pop filters...I'm guessing they were omni electret elements ?

The guitars and bass seem to be DI directly into the PA, no instrument amps ? Phil Lesh describes his (very) active bass guitar as having each string's pickup individually feeding a discrete part of the speaker wall stacks...which must have sounded pretty wild, spatially ! The drum mics look conventional (EV ?)

Check out the following segments:

19:15 - 29:45...for the PA bump-in and Phil Lesh bass guitar

45:34 ...for the remote multitrack recording setup

A nice snapshot of a happier, hippier America

I think a mic splitter was used to send one Mic to the PA for the live show, and one to send to the board to be recorded.

Apparently, Owsley asked engineer Ron Wikersham to create the custom device around the Aoxomoxoa times.

Typically mic splitters are always used to make live recordings, sending one split to the recording feed and the other to PA and monitors.

Or do you mean that the upper mic element (in the Grateful Dead mic situation shown in the video) goes to the PA... and the lower one to the recording ? That would require 2 discrete outputs from the mic, whereas it looks like a conventional 3 pin xlr mic cable in the video, with one output only ?

slightly off-topic but while we're at it:

many mic/line splitters have three (or more) 'legs'. someone gets the non-isolated direct out and hence is in charge of phantom power (typically monitor world) while foh and the broadcast truck get isolated splits. additional split outputs may get used on selected channels for redundancy, doubling inputs (with individual gain trims) for individual processing, feeding emergency units, security services, intercoms, green room etc.

since the advent of digital stage boxes, digital splits could get used but they are not much en vogue so either the old expensive, transformer isolated splitters are still getting used or then less-expensive passive, non-isolated splitters do the trick - together with the detachable plugboxes and stage snakes (often on lk-37), they form an entire 'stage submulticore/splitter system'; some of the smarter designs use a patchbay so incoming signals can get patched in the desired order before signals get distributed to all participants (which is hugely helpful when operating on a 'festival patch')...

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i wish i'd recall where/when the grateful dead's mic setup was explained in detail; maybe in tape op? or mix magazine? in an interview with a veteran engineer in pro sound web ('heritage and history')?

Alright. Let's not overcomplicate things unnecessarily.
Long live the dead.

As I have heard it, that two-mic set up was indeed to counter feedback from the "wall of sound".

A singer would only sing into one mic so the idea that the other mic was for recording doesn't fly. In those days, almost certainly, a splitter was used (maybe direct outs at FOH) if a recording was being made.

The recording truck I worked on for many years had a huge (48 inputs IIRC), very expensive (Jensen transformers), shop-built three way splitter which we sub'd in for the PA company's two-way; FOH, monitors and our truck. The splitter had such a good reputation that no one ever refused our offer.

D.

Nothing over complicated here, ddy was simply illustrating that a mic signal can be split to multiple destinations as required, and that in the era of Dante and similar networks it’s a lot easier to accomplish this than via the traditional heavy transformer isolated splitters.

I'd be really curious to see the inside of one of those boxes. Passive, transformer or some sort of other weird but brilliant electronic plan that those weird but brilliant guys might have come up with somewhere along the line?

I never worked with the band directly but did drive a semi full of some "Grateful Dead Stuff" from Detroit to LA once, straight through without stopping. Ah, those were the days and lucky to be here to tell the tale.

D.

for some of us, grateful dead's appeal lay (at least) as much in the realm of technology as in music (or socio-cultural significance) - because of their use of cutting edge technology and sophisticated techniques (as seen in above video).

i was involved with the original band only once (in the 80s) when i was assisting one of my mentors on a live broadcast (a joint project of the german, swiss and austrian state radio) of the then hugely popular 'rockpalast' where some of the most famous bands of the time (police, santana, grateful dead etc.) performed in a big hall in germany.

iirc the concert as incredibly long, sometimes difficult to make out whether the band was still tuning their instruments, starting a little jam or just developing ideas - 'alabama getaway' stood out in a pleasant way!

rip bear owsley that crazy ****

I like trafo splits (and independent pres and gain structure) a lot but increasingly I get side-ways looks when I suggest or show up with mine. Mostly they want to do Dante etc feeds, or if the board has USB out then that. The custom built trafo multiway splits were the pride of remote trucks back in the day: they were very expensive and usually not rented out, fragile as they were.

I still have a nice one. Can not remember when I last used it. More ramblings from an old guy.

D.

The idea with this system (and there is an AES paper about it from back then) is that the vocal sound coming from the speakers is a planar wave in the near field (and the whole stage is in the near field of the speaker system because there are so many drivers). So if you have two microphones parallel to one another pointed directly at the speaker system and you take the difference, you get only the off-axis sources and not anything on-axis, meaning the speaker sound is nulled out and feedback is mostly eliminated.

That is, the speaker arrangement is designed for that sound-cancelling mike, and that sound cancelling-mike is designed for that specific speaker arrangement. They cannot be separated.

The problem with this is that you do have comb filtering on off-axis sources, which in this specific case means the vocals sound like they are coming through a telephone. There are plenty of good quality recordings of concerts from the Wall Of Sound rig and they all have pretty terrible sounding vocals.

I believe the first generation of the system used B&K mikes but the later versions used some sort of back-electrets (but not jellybean capsules). It didn't really matter much, because the main sonic limitation was the comb filtering effects.
--scott

We all love the dead.

What other examples of bands / artists / individuals using this mic placement / approach can we think of?

According to this extensive Wikipedia description below, none.

“Although it was not called a line array at the time, the Wall of Sound was the first large-scale line array used in modern sound reinforcement systems. The Wall of Sound was perhaps the second-largest non-permanent sound system ever built”

It only served the band for a few months in 1974, before it was ‘retired’ . The October 1974 Winterland S.F concert, as shown in the movie linked in post 1 above, was its final outing. It was broken up and sold at auction many years later

https://en.m.wikipedia.org/wiki/Wall...Grateful_Dead)

put this way, it is simply wrong... - it had elements of what (later*) was called 'line array' but then, the same can be said about speaker clusters predominantly used in pro live sr before (what we now call) 'typical' line arrays became a thing.

it could be called a 'hybrid', showing elements of a line array and a (cluster or rather a wall of speakers typically used for a) point source system.


* i know, the theory goes back much further: what we're still using in many churches (around here) we call 'Zeilenlautsprecher' (in german): there's the 'line' again...

...but it takes a lot more effort for a speaker system to behave as a line (array) over a very wide frequency range and to maintain it over a large distance (as far as that's possible at all)!

Nobody. Nobody in their right mind would ever use this kind of speaker system.

This is not a line array. If anything, the vocal array was a panel array since as I said the intention was to create a planar wave. But the speaker system consisted of multiple speaker arrays with different radiation patterns, all reproducing individual instruments.

The Dead very quickly gave up on the system, more because it was impossible to tour with than because of the sound.
--scott

It really wasn't a great idea, actually.

D.

I know very little about the Dead, but I vaguely recall hearing that their engineers also experimented with some kind of vocal mic gating system, controlled by proximity sensors (?) or something like that, so that the mic would be gated when the singer stepped away from it. I don't have a reference for this "possible fact".

not sure they were the first but the 'optogate' became quite popular - now i try to avoid using gates like the plague (i'm using expanders instead) but i have to admit that they've saved my ass on more than one occasion; imo they are helpful on a busy stage (and/or loud) stage. if using any, it's mostly on backing vocals or horn section...

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...but let me quickly get back to the their über-pa: there is one aspect in which it was indeed ahead of its time - the idea of assigning individual instruments to different zones within the wall and the resulting localization of the instruments within the soundfield was revolutionary, but this simply could not be credibly achieved with the possibilities of the time: the effect may have lasted until the edge of the stage.

with today's means (even if only under suitable conditions and with enormous effort), it is possible to hear sources within the panorama both immersively and precisely: perhaps you have already experienced concerts or at least seen pictures of pa's being flown in several hangs above the stage - then you also need trackers on the instruments and a clever processor (essentially a delay matrix) and you can let sound sources wander around (at least in the horizontal plane) without someone at the mixing desk having to adjust the joystick! this is regularly getting used here in larger productions for plays/operas and musicals...

When the "Wall" became too much for even the Dead's crew to deal with that made an opportunity for a tech named John Meyer, who built its successor. That system toured with the band forever, all over the world. Dan Healy, the Uber Mixer and architect of the Dead's sound, referred to that Meyer system as his instrument, his Stradivarius.

Yes, that was many years later with a more conventional sound system. A similar device was later available commercially and was advertised in the back of Sound and Communication magazine for years.
--scott

Man rockpalast was great. The Smiths one was incredible. If memory serves I believe I saw the dead play shakedown street on there.

i very rarely remember specific songs (not to speak of entire set lists) - i do sometimes remember details though, such as input patches, specific equipment choices, etc. but after thousands of shows in more than 40 years, things start fading.... - in the case of the dead's gig for rockpalast, the broadcast mix was done on a (ridiculously heavy) mci jh-536 (which i later bought and kept using for ca. 20 years) and for redundant recording (in case something should have gone wrong with the live broadcast), a pair of studer a-800's were used - in my memory, i was constantly changing reels...

Some writers here are overcomplicating the design of the Wall of Sound speaker systems and the effect of the paired out-of-polarity omnidirectional vocal mics.
The paired vocal mics were stacked and very close together. When the singer stopped singing and backed off the top mic, the pair canceled almost entirely. The vocal stacks had only vocals in them. The band members, especially Weir, were very good at eating the top mic. Anyone who tried to work the mic close and far, as is somewhat a common practice among non-metal singers, would cause abrupt unmusical and unintentional variations in vocal level and sound quality.
Likewise, each instrument had its own stacks and instruments did not share speakers.
All stacks were powered by a number of high end stereo hi-fi amps in stacks. I don’t remember the brand.
I heard the Wall of Sound once at Winterland (sounded wonderful), once at Kezar stadium with a number of “normal” PA speaker added (sounded very good), and once at the Hollywood Bowl. At the Bowl, the height of the seating area made the vertical “beaming” of all the stacks a serious problem. If you as an audience member were in the vertical “sweet spot”, the system sounded good. If the audience member was above the top of the line arrays, the system sounded weak, odd, and unbalanced. My ticket was for a very high seat, and I could only steal into the better seats a couple of times, where I was quickly asked to leave. I didn’t go to any later Dead shows.

Yeah I used to have the Rockpalast show in VHS back in the '90s. They did do Shakedown St. and they had Pete Townshend come out to play Not Fade Away with them. Great show.

https://www.mcintoshlabs.com/about/n...-wall-of-sound

Thanks. Our band couldn’t afford McIntosh…. or much of anything else that made up the Wall of Sound.