Korgscrew
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Joined: Dec. 1999 |
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Posted: Jan. 29 2009, 02:19 |
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In the days before transformer isolated splitters (and after that, the days before it was common practice to have them available), having a second mic was the best way of getting a second feed. It does seem like the most common reason to do it was for recording purposes (having not seen that Genesis DVD, I don't know what they would have done about the other instruments...it's possible they were recorded by other means, or that - particularly believable in the case of guitars - weren't going through the PA).
It would equally have given a good way of feeding the vocals to a separate amplifier so that the singers could hear themselves better, in days when monitoring was still in its infancy (and really, using a mic for that isn't wasting it - they 'waste' a whole mixer and engineer for monitoring these days! ). I don't know what kind of set up Genesis would have had at that stage, but my guess is that they probably would have had more sophisticated monitoring arrangements than that in 1973, but that really is only a guess.
The two mic technique for recording still gets done now, usually for a different reason. Hayley Westenra sang into two mics at the Music of the Spheres premiere - one was a studio condenser (a C414 if my memory serves me correctly) for the recording and a less sensitive and feedback prone Sennheiser dynamic mic for the PA. I have a feeling that at least some of the instances of two mics taped together in 60s/70s concerts have been condenser/dynamic combinations, in fact.
There are some other reasons two mics might be used on one singer, though I don't think any apply here.
Having a pair angled inwards towards the singer is sometimes done in a classical setting, to help give even coverage when the singer moves his/her head; it's a common one with politicians as well (though as a side note, the two SM57s on the US president's podium are apparently used to provide separate feeds, as well as being there in case one fails - that's why they're right next to each other, pointing forwards; the basic setup hasn't changed since 1968). That's always done with them more distant, though.
The same goes for stereo recording - they need to be a certain distance away for it to give anything like an accurate image. It's also important that the spacing and angle (and they do need to be angled to make a useful coincident pair) between them remains constant, which means putting them in a stereo mount of some description - gaffer tape really isn't good enough (though it might work if the mics aren't going to be touched at all). Miking a singer in stereo at a rock concert would cause all sorts of problems later on in the mix, though and in terms of a PA mix, it would be fairly disastrous - the important things like vocals need to be kept at the centre of a live sound mix so that people get a good balance even if they're right over by one side of the stage...you can get away with using a bit of panning as a special effect, but going much further can be asking for trouble.
Yet another technique involves having one mic to sing into and another picking up ambient sound - the polarity of one is then reversed so that, in theory, the ambient noise gets cancelled out and all that's left is a nice clean vocal. The Grateful Dead used this technique in the 70s, but I've read that they didn't manage to avoid the thin vocal sound that resulted from the vocals getting cancelled as they were picked up slightly by the second mic. Their mics were also on a rigid double mount rather than taped together.
All three of those techniques need the mics to be matched, so condensers are normally used (you can do stereo with ribbon mics, but that's a whole different story...).
So...clumsy as it may seem, the separate feeds explanation is actually the most likely.
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