# What were those double vocal mics in the 60s all about?



## Guncho (Jun 16, 2015)

You know when you watch concert footage from the '60s all the singers had those double mics. What was that all about? Why does no one do this anymore? Something to do with eliminating feedback that is no longer required?


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## bzrkrage (Mar 20, 2011)

THE VOCAL SYSTEM


A major improvement in the quality of the vocal sound is due to the use of differential microphones. Each singer has a perfectly matched pair of Bruel and Kjaer microphones hooked up out of phase, only one of which he sings into. Any sound which goes equally into both microphones is cancelled out when the two signals are added together. Therefore leakage of instruments and background noise into the vocal channel is minimized.

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[Responding to the Grateful Dead's philosophy of providing as clean a sound as possible to all members of the audience in ever larger concert situations, the Wall of Sound evolved from the practical experience and design ideas of the band's sound engineers, Alembic Studios, and the Bear in the early 1970's. After the Grateful Dead's "hiatus" of 1974/1975, Public Address Systems technology had moved forward and the era of smaller, versatile systems pioneered by Healy, Ultra Sound and Myers began. - Editor, 1998.]


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## Guncho (Jun 16, 2015)

So why is that no longer needed for live vocals?


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## Guncho (Jun 16, 2015)

Ok so the dead this to cancel feedback as their PA speakers were behind them but research says most other times singers did this so they would have one signal for the pa and another for monitors/recording.


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## neilg1 (Aug 21, 2019)

Wall of sound was behind the band. No monitors in front. So the massive PA hit the mics too. This was an ingenious invention by Owsley Stanley and co to cancel out the PA from the mica to avoid massive feedback problems.


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## Chito (Feb 17, 2006)

Guncho said:


> Ok so the dead this to cancel feedback as their PA speakers were behind them but research says most other times singers did this so they would have one signal for the pa and another for monitors/recording.


One to PA and one for recording was what I thought it was all about. You learn something new every day.


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## cbg1 (Mar 27, 2012)

Chito said:


> One to PA and one for recording was what I thought it was all about. You learn something new every day.


Me as well... love this place


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## bzrkrage (Mar 20, 2011)

Guncho said:


> So why is that no longer needed for live vocals?


Better PA speaker design, less noise floor, better cardioid microphones, the use o lower impedance is such as the Shure SM58 (revolutionary! ) 
Cab isolation, independent fold back or IN ear monitoring allowing a much truer sound to the microphone.


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## bzrkrage (Mar 20, 2011)

neilg1 said:


> Wall of sound was behind the band. No monitors in front. So the massive PA hit the mics too. This was an ingenious invention by Owsley Stanley and co to cancel out the PA from the mica to avoid massive feedback problems.


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## Guncho (Jun 16, 2015)

I can't imagine that was good for your ears if you were onstage. it must have been insanely loud.


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## ezcomes (Jul 28, 2008)

back then PA systems weren't abe to keep up with the required sound requirements...so they used multiple PA's to get the sound out...each mic to a different system, to pump out the volume to meet the crowd and keep up with the cranked plexi's

PA's got more advanced, FOH asked for quieter amps, now we are at the lunch box amp time as they can get their sweet spot without overpowering the stage sound and gets pounded out by the PA


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## zach_s (Jan 6, 2022)

Guncho said:


> You know when you watch concert footage from the '60s all the singers had those double mics. What was that all about? Why does no one do this anymore? Something to do with eliminating feedback that is no longer required?


i think conceptually double mic use this way is similar to the use of balanced inputs and connections.
feed them to a differential amplifier they will "subtract" the "noise".

noise being anything other than the signal you want to pass on its own.

in the case of copper connections this would be hum and other gremlins.


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## Sneaky (Feb 14, 2006)

ezcomes said:


> back then PA systems weren't abe to keep up with the required sound requirements...so they used multiple PA's to get the sound out...each mic to a different system, to pump out the volume to meet the crowd and keep up with the cranked plexi's


They used banks of McIntosh hi-fi amps to power the wall.


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## neilg1 (Aug 21, 2019)

Great article about the WOS here if interested in more.


The Wall of Sound - VICE



Also check out luthier Anthony Coscia, who has been building faithful scale reproductions of the whole Wall. Wild stuff.









Anthony Coscia Recreates A Grateful Dead Legend With Mini Wall Of Sound Project [Interview]


Connecticut luthier Anthony Coscia used his quarantine-imposed downtime to recreate a mini version of the Grateful Dead's Wall of Sound.




liveforlivemusic.com


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## Granny Gremlin (Jun 3, 2016)

Guncho said:


> Ok so the dead this to cancel feedback as their PA speakers were behind them but research says most other times singers did this so they would have one signal for the pa and another for monitors/recording.


This is conflating 2 things: feedback suppression and noise rejection.

For noise suppression the second mic was facing backewards (inverts phase and ensures the vocals aren't cancelled out - if both front facing you're cancelling out a lot of vox becasue you can't not sing into the second mic - best case you get old radio/telephone tone).

If both mics face the singer that is an attempt to reduce feedback by running 2 mics both at lower gain setting vs 1 at higher gain. Doesn't always work so well as stuff can be cumulative but usually you can get at least a bit more gain before feedback in this way. As stated above the SM58 revolutionalised live sound in many ways (LoZ not being one of them; that already existed, but it is true that HiZ mics did have a lower feedback theshold, and those were still popular not because the mics didn't exist, but because the mixers, on the low -med end of the market at least, used HiZ inputs) but off axis rejection (better cardioids) and gain before feedback were huge improvements. Another way they cut feedback (especially with HiZ mics) was via the use of notch filtering - very narrow-band and deep EQ cuts. Sometimes this was also used in a comb filter arrangement (multiple notch filters at intervals along the frequency spectrum). The idea was to tune into the freq(s) of the feedback and cut them out, leaving most of the desired signal intact. A legacy of that is the feedback rejector EQs on many old Traynor and later "console" style Garnet PA mixer/amps (e.g. YVM-6 and Pro Vocal).









The Traynor was solid state and you can see the filters between the input channels and master section. The Garnets were tube. Couldn't find a good pic of a Pro Vocal Console (4-6 filters IIRC) but here's the smaller Tripper Console, which has 2 progressive filters (vs fixed cut on/off switches on the Traynor) right next to the power switch :











Sometimes they'd be doing both (noise and feedback rejection) so you'd see 3 mics taped together, one backwards. This really limited the vocalist, especially if not also a guitarist (or whatever) because you can't take the mic off the stand and jump around. And it looked ghetto as shit.

They may have sometimes been doubling up for feeding different sources, but they did have transformers back then so they could have just split the single line at the console or stage box (which is what we do now, though we also have active devices for that in addition to transformers and mixers with 'direct outs' on input channels, tranformers are still used for this though - the the Radial mic splitter box, as well as units with mutiple channels of passive transformer based splitting).


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## neilg1 (Aug 21, 2019)

To be clear - the two mics are out of phase. 
you sing into only one of them. 
both “hear” the PA behind you. 
phase cancels the PA noise, and leaves the vocals only. Thereby avoiding feedback and providing an isolated vocal track, which went individually per band member to personal speakers in the curved array above the stage.


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## Guncho (Jun 16, 2015)

Granny Gremlin said:


> This is conflating 2 things: feedback suppression and noise rejection.
> 
> For noise suppression the second mic was facing backewards (inverts phase and ensures the vocals aren't cancelled out - if both front facing you're cancelling out a lot of vox becasue you can't not sing into the second mic - best case you get old radio/telephone tone).
> 
> ...


I use to own that exact Traynor PA.


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## Granny Gremlin (Jun 3, 2016)

neilg1 said:


> To be clear - the two mics are out of phase.
> you sing into only one of them.
> both “hear” the PA behind you.
> phase cancels the PA noise, and leaves the vocals only. Thereby avoiding feedback and providing an isolated vocal track, which went individually per band member to personal speakers in the curved array above the stage.


I get the concept of phase cancellation (differential inputs etc) but you can't sing into only one of them if they are side by side - the second mic will pick up almost if not as much vocal as the primary. You'd cancel out a lot of vocals in the bargain to the point of not being worth it. If they are HiZ single ended mics (never seen HiZ balanced) you also can't flip the phase at the console (this is done with balanced XLR inputs by switching pins 2 and 3 - thats all a phase switch on a mixer does). One mic had to be backwards (picks up crowd noise, but not vocals; rely on the singer's body to block amps, as well as spacing them further to the wings and towing them out) and is de facto in opposite phase by virtue of facing the opposite direction (see micing drums from both top and bottom at once).

You could do that with a spaced pair (second remote mic picking up stage noise, like at least a few feet away from the vocal mic, like at the knees vs mouth, or off to the side), but then it's not taped to the primary mic on the stand, and you need a balanced line to do it (or a complicated device to flip the phase on a single ended line that was never built in to mixers and I have never seen as a commercial product, but could be DIYed in both tube and solid state eras - bit of a pain so don't think that was common).



Guncho said:


> I use to own that exact Traynor PA.


So did I. Great reverb and the the discrete transistor input channels sounded great too.


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## Guncho (Jun 16, 2015)

Granny Gremlin said:


> You can't sing into only one of them is they are side by side. You'd cancel out a lot of vocals in the bargain. If they are HiZ single ended mics (never seen HiZ balanced) you also can't flip the phase at the console. One mic had to be backwards (picks up amps and crowd noise, and is de facto in opposite phase).
> 
> You could do that with a spaced pair (second remote mic picking up stage noise), but then it's not taped to the primary mic on the stand.
> 
> ...


It would be awfully funny if I bought it from you years back. I sold mine to some restaurant in TO.


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## neilg1 (Aug 21, 2019)

You can say you can’t sing into only one (one on top of the other), but that is exactly what they did for 5 or so years until carting the wall around almost bankrupted them


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## Guncho (Jun 16, 2015)

The mics the dead used sounded really good, especially given their small size.


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## neilg1 (Aug 21, 2019)

I was too young to see the Wall in action, but people who did said it was unreal. Clear as a bell to the back of the field.


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## Granny Gremlin (Jun 3, 2016)

Guncho said:


> It would be awfully funny if I bought it from you years back. I sold mine to some restaurant in TO.


It would but no, my Traynor mixer had the power section removed by a previous owner, and I cannibalized it for parts after aquiring a better (more modern) powered mixer. It was well built with quality parts. Used it for jam PA and then as a reverb send for mix downs, and the parts from it are still making their way into my pedal builds (lot of tropical fish style caps, mostly 100n which is a super common value in pedals).

I still have the water purifier pump I bought from you 15 years ago.


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## Guncho (Jun 16, 2015)

Granny Gremlin said:


> It would but no, my Traynor mixer had the power section removed by a previous owner, and I cannibalized it for parts after aquiring a better (more modern) powered mixer. It was well built with quality parts. Used it for jam PA and then as a reverb send for mix downs, and the parts from it are still making their way into my pedal builds (lot of tropical fish style caps, mostly 100n which is a super common value in pedals).
> 
> I still have the water purifier pump I bought from you 15 years ago.


Hmm I don't think I sold you a water purifier pump. Like for a house?


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## Granny Gremlin (Jun 3, 2016)

neilg1 said:


> You can say you can’t sing into only one (one on top of the other), but that is exactly what they did for 5 or so years until carting the wall around almost bankrupted them



In Pink Floiyd's case, it would be more feasible - a vocalist with chops (mic technique) who could be trusted to stay right on the main mic (vs when you see this at festivals , like Woodstock with a bunch of randos you can't control). Still I find it unlikely. It also means the vocalist CANT back off the mic or really move at all - upper lip always in contact with the grille, so you need compression which they didn't have earlier (the vocal attack in The Wall is very dynamic even within songs never mind song to song). Also, by the time of The Wall they had much better gear so this wouldn't be required (I don't recall any footage of that tour with double mics). That was 80-81; the SM58 came out in 66, but wasn't all that common until the 70s (especially among the less pro musicians). The lines were all balanced XLR and they had wicked outboard processing.

Here's some early bootleg footage from 1980 - clearly only a single mic (looks large - AKG C1000 or something) and headphones vs monitors so the acoustic wouldn't feed back (see 23:40ish for a close up shot... and then 39:11 for same vocal mic but electric guitar so no cans).






Possibly you're mixing up your tours; I'm sure they did the double mic thing earlier in their career.



Guncho said:


> Hmm I don't think I sold you a water purifier pump. Like for a house?


No for drinking water when camping. It was totally you.


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## Guncho (Jun 16, 2015)

Granny Gremlin said:


> In Pink Floiyd's case, it would be more feasible - a vocalist with chops (mic technique) who could be trusted to stay right on the main mic (vs when you see this at festivals , like Woodstock with a bunch of randos you can't control). Still I find it unlikely. It also means the vocalist CANT back off the mic or really move at all - upper lip always in contact with the grille, so you need compression which they didn't have earlier (the vocal attack in The Wall is very dynamic even within songs never mind song to song). Also, by the time of The Wall they had much better gear so this wouldn't be required (I don't recall any footage of that tour with double mics). That was 80-81; the SM58 came out in 66, but wasn't all that common until the 70s (especially among the less pro musicians). The lines were all balanced XLR and they had wicked outboard processing.
> 
> Here's some early bootleg footage from 1980 - clearly only a single mic (looks large - AKG C1000 or something) and headphones vs monitors so the acoustic wouldn't feed back (see 23:40ish for a close up shot... and then 39:11 for same vocal mic but electric guitar so no cans).
> 
> ...


Oh that's possible for sure.

Man VHS fucking sucked. Sometimes I think about how we have all this amazing footage of historic bands live in the 60s and 70's and then there's going to be a huge hole where we have no quality video of live performances.


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## zach_s (Jan 6, 2022)

neilg1 said:


> To be clear - the two mics are out of phase.
> you sing into only one of them.
> both “hear” the PA behind you.
> phase cancels the PA noise, and leaves the vocals only. Thereby avoiding feedback and providing an isolated vocal track, which went individually per band member to personal speakers in the curved array above the stage.


thanks Neil and gremlin for the tutorial. clarifying vs mystifying.


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## Granny Gremlin (Jun 3, 2016)

I just realised he was talking about the Greatful Dead not Pink Floyd. He did say 'the wall" and touring until bankrupt, and made no mention of any band name (in that post).

Anyway, looking at pictures of that, the main issue is, forget about bleed, feedback considering the entire field of pickup for the vocal mics is full of PA. Must have been a bear of a job running that (pun intended). It's hard to find good pics to see what's going on with the mics, nevermind video. There was one where I thought I saw a ball-end facing the audience but hard to be sure. Then there's other pics where it looks like 1 mic each, others definately 2 singer-facing. I suspect there was some experimantation over time ( the whole thing was constantly evolving by Owsley's own account - he kept journals). This one is clear though (especially if you copy it local and zoom) - 2 mics facing the singer, one angled slightly down and spaced with some device in between. This is important because it is unique - nobody else did this. Notice also how Jerry is fellating that mic - he had to for this to work (as I explained earlier). Notice the couple inches between ball ends (vs the usual case where they are literally taped together vs this very deliberate custom made mount - all 3 mic positions have identical setup), the specific downward angle of the second mic (not too much to put it out of phase significantly - so that when you flip it it is near perfectly out of phase, but enough to get the vocals off axis; weaker pickup in the second mic - especially in the higher registers where pickup drops off quicker as you move around the mic, also the, usually, band most prone to feedback), and the vocalist being right up on the primary. All the problems with this setup I spoke of earlier.










There is only 1 cable coming off the mic stand and it is an XLR connector, the device in between mics may be more than a mount - somewhere in that rig (it may be in the chunky XLR Y cable vs the box between the mics) must be a passive summing device (crude mixer - you only need a couple resistors for that - could easily fit into a cable assembly or XLR barrel connector) that also switches pins 2 and 3 on the bottom mic (which takes no more space than normal wiring; I don't mean switched as in switchable; just wired up backwards in a fixed fashion). They are not doing that at the mixer, as most everyone else did, but at the source, which is interesting and has the advantage of requiring less channels on the mixer and less cable running. So @neilg1 is right in the specific case of The Dead's early shows (they did drop the multi mics later), but there seems to also have been a few other configurations tried earlier on as they figured this out. This was only required because of the Wall of Sound - literally blasting the vocal position with arena-level volume, directly on axis with the microphone(s). It does not apply to any other show from that period (where multi mic setups were also used), which was the general question at hand. It's cool but at the same time I'd have to be on acid to wanna deal with that as the sound engineer - there's a reason that nobody else did this (besides economics - people cart around larger systems today, or at least up to the 80s-90s - now they mostly rent local except in specific cases where they want to use specific non standard stuff - like I forget who but someone recently was using a Neve 5088 as a live console which I found remarkable - no concert logistics company would be able to supply one to you; they've mostly gone all digital at this point anyway).

The reason this never caught on, obviously, is that the singer can't go anywhere or even back off the mic at all (while singing) - they must remain glued to it for it to work. This was fine for Garcia and co, due to a) not being stage wanderers or dancers to begin with, and b) their very steady vocal attack - consistent mellow crooning with few (none that I can recall but I'm no deadhead) more emphatic random bits (like within a song - song to song changes could be accounted for easily at the mixer, and some gain riding or compression during a song could take care of such a relatively easy case, vs contemporaries like Van Morrison who were all over the place).


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## Sneaky (Feb 14, 2006)

I remember “Lips” Kudlow in Anvil used to use a pair of SM-58’s for vocals.


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## neilg1 (Aug 21, 2019)

Gremlin- correct all around as far as I know.
In context this set up is insane. The Dead saw the Beatles etc play out of stage amps into massive venues and said this is not a reasonable experience for a fan that actually wants to hear the music. So was born the Wall of Sound. The logistics of the rig, for a band playing 100-150 shows per year, ultimately did it in. They had something like 18 flat bed trucks to cart it venue to venue. In duplicate!!! So the crew could leapfrog itself to the next stop.
they shipped this rig to Europe in ‘74!
Tons of history - both technical and biographical on this system all around the web. But it’s credited as the father of the modern concert PA, and would have been a wonder to see and hear.
Pretty much all Deadheads, myself included, will be found with a rig inspired by this - something like a BF Twin preamp, solid state power, and 12” JBL speakers. Clear as a bell.
They’ll ring like fire if you lose your way (~);}


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## neilg1 (Aug 21, 2019)

Adding one of my favourite pics of the wall in action.


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## Granny Gremlin (Jun 3, 2016)

neilg1 said:


> Gremlin- correct all around as far as I know.
> In context this set up is insane. The Dead saw the Beatles etc play out of stage amps into massive venues and said this is not a reasonable experience for a fan that actually wants to hear the music. So was born the Wall of Sound. The logistics of the rig, for a band playing 100-150 shows per year, ultimately did it in. They had something like 18 flat bed trucks to cart it venue to venue. In duplicate!!! So the crew could leapfrog itself to the next stop.
> they shipped this rig to Europe in ‘74!
> Tons of history - both technical and biographical on this system all around the web. But it’s credited as the father of the modern concert PA, and would have been a wonder to see and hear.
> ...



Altecs not JBLs ;P (but that's a small difference). And they did use JBLs later.

I get why people see this as the start of modern PA, but there are some key points that are not included - like everything that is problematic with it re the vocal mics. It did make them heard and allowed them to hear themselves (which was the Beatles' problem). The key to modern PA was separating front of House from stage monitoring (though I believe this is problematic in other ways, especially as executed in small to medium clubs; in larger venues they have solved this with in ear monitoring.... which has a few non-audio problems of its own) and more importantly, having the PA be in front of the performers (and therefore the vocal mics) eliminating that whole issue. Certainly awesome and a step along the way.

I was never a very orthodox sound man and it's interesting to see how some of this aligns (and doesn't) with my own ideas for a better arrangement which include Jamaican sound system influence.


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## 2N1305 (Nov 2, 2009)

Granny Gremlin: Jamaican sound system influence?


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## Granny Gremlin (Jun 3, 2016)

2N1305 said:


> Granny Gremlin: Jamaican sound system influence?



Have you seen a Jamaican sound system? They did the wall of speakers thing too (as well as active systems with crossovers feeding separate hi and mid/bass cabs before that really caught on), and also loved their Altecs and JBLs (when they could get them).


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## 2N1305 (Nov 2, 2009)

Ah. Je comprends. Thanks for that. I must seek info on this.


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## Alan Small (Dec 30, 2019)

Guncho said:


> I can't imagine that was good for your ears if you were onstage. it must have been insanely loud.


What???


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