This past week PBS had a major fundraiser, which included many shows. One was a gathering of many of the reknown Rock and Roll pioneers and the other was a major Bluegrass concert. No high power stage theatrics, just excellent music from some of the most talanted musicians and pioneers...Another excellent group that played together was the Million Dollar Band that played together on the old TV show "Hee-Haw". Does anyone watch Austin City Limits?
Here in 'Vegas it's common practice to back-up the lead singers of production shows with tape or HD tracks. If a mic dies, pot up the track. Of course nowadays all of the non-lead music comes from tracks, live orchestras having died here in 1989.
Paul
Greetings from the land of the thrice kissed ass
Unemployed
mercenary film/video projectionist/engineer
"When the money runs out, so does I."
-1
The first instance of musical acts using sweetened tracks on live shows that I can recall would have to be Jan and Dean, after that horrible car wreck. But it was soon accidentally revealed during a live show.
Wouldn't it be great if the computers shut down on a britney show leaving her with just her voice. To make sure that the truth is out, she does sing during her shows, a total of 10 percent level volume to a 90 percent sweet track. Hey, maybe her body will hold out.
Dave
During the actuall shows, the choir sings on stage with NO mics, but the sound coming from the cluster overheard is glorious. No one in the audience knows (with the exception of us guys in the sound booth).
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Barry Floyd
Floyd Entertainment Group
Nashville, Tennessee
(Drive-In Theatre - Start-Up)
If I am paying to see a live show and the proformers are putting my money in their pocket...thay had best not be lip syncing. I don't go to see them, I go the hear them...the talent is in the voice not the looks.
No, say it ain't so! Was it in "History of the World" where Moses drops the tablet with Commandments 11-15 on it? Thou Shalt Not Lip-Sync!
Lip synching, not even singing at all or not able to hear the actual singing goin on while performing, is just evil.
Dave
One of the things that gave away Milli Vanilli was a performance they did on MTV. During the song "Girl You Know It's True" the digital tape being used got caught in some endless loop where the main phrase of the chorus just repeated over and over and over again like a scratched record.
A follow up album where the two dreadlocked fellows actually sang tanked badly. A couple years ago one of those guys killed himself.
quote:
It is logistically impossible to run 24 give or take a dozen live mics at once on stage. best to have the performers sing to a pre recorded track of themselves singing on that same stage. Otherwise the feedback loops are so horrendous that all would be bleeding from the ears in seconds.
Not impossible at all. Here, in the case of shows with live orchestras (rare now but still happens), we routinely run with that many mics or more open simultaneously on stage. Yes the feedback nodes can be difficult, but not impossible. Today's signal processing options make it even less impossible.
On Starlight Express (1994-1997) at the Las Vegas Hilton we had 30 singers (all on roller skates) wearing RF boom mics, with two handheld RF mics available as spares. The finale and bows had the entire cast on stage singing in unison. Two shows a night, six nights a week, with very few problems. On that show the producers decided there would be no backup tracks--if a mic quit, one of the handhelds would be run out to the perfomer. They even made a point of it by announcing at the top of the show that the entire show was performed live. Admittedly the "orchestra" was three guys playing sampling keyboards all MIDI'd and sequenced together, which resulted in some pretty funny sounds coming from the pit (actually a room backstage) during the occasional MIDI crash. But that's another topic.
So in the end one could say that show had at least a partially canned band, but the 30 singers were all live.
Paul
My favorite Las Vegas soundman's t-shirt, printed by Steve Varner at Local 720:
"Everyone in the world knows two things:"
"1. Their name"
"2. Sound" 
-0
"It is logistically impossible to run 24 give or take a dozen live
mics at once on stage."
Whoa... thats not too many mics. I have done shows with 67 live mics on stage (Beatlemania, 1998 -- symphony orchestra + the band) and 8 monitor mixes. It is difficult to control feedback, but certainly not impossible. A good FOH engineer will use the PA to REINFORCE the musicians, in much the same way that sweet tracks can be used to back up lead vocals. It may also be necessary to provide AMPLIFICATION if you're in a 15,000 seat arena, in which case nothing changes. You just have to be a little less subtle 
To cash in on US jingoism Arista Records rush-released her Super Bowl performance as a cassette single. A few weeks later the New York Post reported that Ms. Houston never sang "The Star-Spangled Banner" at the Super Bowl. Why not? She lip-synched! Arista was forced to withdraw that record from record stores. Her career would have crashed had it not been for The Bodyguard.
FWIW Arista was also the US label for Milli Vanilli -- whose own lip-synching scam was exposed a few months earlier.
I do accept that it is possible to do a cagillion mics with no feedback.
from my own experience i have ran 22 mics to a drum set plus an addition 12 mics for various items. All perfectly.
I brain farted when I wrote the post and missed a few points. My key point to say that sometimes in many different types of shows, mostly broadway and choral in origin, have to use sweetened tracks to avoid using all the mics. The mics in question are the body mics that use a omnidirection pickup pattern, allowing for creative placement of microphones to allow for costuming to conceal it. These mics can have the sensitivity turned down to a certain extent to avoid the problem, but depending on the acoustics and the relevence of blocking with the stage size, you can end up in pure sound engineering hell, or in heaven, it all depends on what you have to work with.
My only point was to point out the sometimes necessity of sweet tracks in the case of hellish acoustics.
Dave