Topic: 60' and 70's P.A Question

[Frequincy]

Iv'e seen photos of several singers performing from this era with two mics taped together. I was wondering if anyone might have some insight as to why this was done? At first I thought maybe one mic went to FOH and the other was for monitors. Then I read somewhere it might be a technique used to reduce feedback. Or did one go to a tape machine? Just curious.

[eric.B]

http://www.prosoundweb.com/article/the_wall_of_sound_to_now_a_pa_evolution_odyssey/

http://www.gearslutz.com/board/remote-possibilities-acoustic-music-location-recording/40220-ozzy-plant-2-mics-taped-together.html

::They were supposed to kill feedback. Two microphones were wired out of phase. In close proximity like that will cancel each other out if the same signal, with the same strength is applied to both. If you sing into the closest one, your voice won't be canceled out (that signal being much stronger than the one going in to the second mic). The sound returning from the pa speakers though would enter both mics at pretty much the same level and at the same time, causing phase cancellation and avoiding feedback.

Try it. It really works. Nowadays, the intelligent graphic equalizers will solve the issue in a more elegant way..::

OR



 
Join Date: Sep 2007
Location: ontario, canada
Posts: 150
   
yes, the two mic taped together thing is indeed to eliminate feedback, as monitor systems were in their infancy (if they were used at all), and most times there was either the PA on its own, or very large sidewash systems. if you look at old footage of the stones, mick can be seen using this technique.

also, as a sidenote re: the grateful dead's massive system...everyone did in fact have their own stack behind them, but the reason why the FOH guy had no control over anyone's sound was because there WAS no FOH guy. there were people giving feedback to the band so it remained more or less balanced, but there was no console to be wrangled. (this VERY large system was run completely on tube powered amps as well, making it the most labour-intensive PA to ever be built, and ultimately led to its demise due to the unbelievable cost involved in its upkeep.)

[rokpunk]

simple answer was that the 2 mics were thrown out of phase in an attempt to kill feedback. in theory, it makes sense, in reality, it's not very effective.

[ArchivalAudio]

I was gonna say the Wall Of Sound!
the Dave Rat article is very good

the entire concept is quite interesting, though, I think today's PA's are sonically (or can be) superior

thanx
-- Ian

[datbrad]

simple answer was that the 2 mics were thrown out of phase in an attempt to kill feedback. in theory, it makes sense, in reality, it's not very effective.

It was effective for the Dead as far as feedback reduction, it just did not sound very good, even with the B&K caps they were using.

[rokpunk]

simple answer was that the 2 mics were thrown out of phase in an attempt to kill feedback. in theory, it makes sense, in reality, it's not very effective.

It was effective for the Dead as far as feedback reduction, it just did not sound very good, even with the B&K caps they were using.

if it doesn't sound good coming out of the speakers, then it's not very effective as a part of a PA system, now is it?

[datbrad]

simple answer was that the 2 mics were thrown out of phase in an attempt to kill feedback. in theory, it makes sense, in reality, it's not very effective.

It was effective for the Dead as far as feedback reduction, it just did not sound very good, even with the B&K caps they were using.

if it doesn't sound good coming out of the speakers, then it's not very effective as a part of a PA system, now is it?

No, it definately would not be. But, while you might have a different experience, in person I am told, the Wall Of Sound was incredible even in the vocals, according to my old Deadhead mentors that saw several shows using it in 1974. The few genuine high fidelity audience recordings I have heard that were made then sound nothing like the SBD sources of these shows that 99% of people are used to, so I am thinking that maybe the weird sound that the dual mics created was not normally as pronounced live from the PA as it was on SBD tapes.   

[sparkey]

simple answer was that the 2 mics were thrown out of phase in an attempt to kill feedback. in theory, it makes sense, in reality, it's not very effective.

It was effective for the Dead as far as feedback reduction, it just did not sound very good, even with the B&K caps they were using.

if it doesn't sound good coming out of the speakers, then it's not very effective as a part of a PA system, now is it?

No, it definately would not be. But, while you might have a different experience, in person I am told, the Wall Of Sound was incredible even in the vocals, according to my old Deadhead mentors that saw several shows using it in 1974. The few genuine high fidelity audience recordings I have heard that were made then sound nothing like the SBD sources of these shows that 99% of people are used to, so I am thinking that maybe the weird sound that the dual mics created was not normally as pronounced live from the PA as it was on SBD tapes.   

Any of those recordings on archive.org?

[darby]

simple answer was that the 2 mics were thrown out of phase in an attempt to kill feedback. in theory, it makes sense, in reality, it's not very effective.

It was effective for the Dead as far as feedback reduction, it just did not sound very good, even with the B&K caps they were using.

if it doesn't sound good coming out of the speakers, then it's not very effective as a part of a PA system, now is it?

No, it definately would not be. But, while you might have a different experience, in person I am told, the Wall Of Sound was incredible even in the vocals, according to my old Deadhead mentors that saw several shows using it in 1974. The few genuine high fidelity audience recordings I have heard that were made then sound nothing like the SBD sources of these shows that 99% of people are used to, so I am thinking that maybe the weird sound that the dual mics created was not normally as pronounced live from the PA as it was on SBD tapes. 

Any of those recordings on archive.org?

check this one out:
http://www.archive.org/details/gd1974-07-21.ecm22p.bertrando.89033.flac24

[Frequincy]

thanks to all for the info. I have many Dead shows and will have to check out that era of my collection. I remember when I was a teen and seeing a Black Sabbath vid and saw the 2 mic config and had no clue what that was all about. It's amazing how technology has changed with in ear monitoring and line array systems. The history is facinating.

Awsome link Darby!!!! Crystal clear and beautiful.