Applying 3:1 mic rule with groups

jack63ss

Member
I have a group of 50+ on stage, usually in 4 rows, about 10' from the edge of the stage. At times there are groups of 6-10 that stand in a line about 6' from the edge of the stage. I usually mic them with 4 mics spread equally across the edge of the stage, but this breaks the 3:1 rule as they are only about 10' apart. I am looking for suggestions on how to improve this layout.
Thanks
Jack
 

MRW Lights

Well-Known Member
I have a group of 50+ on stage, usually in 4 rows, about 10' from the edge of the stage. At times there are groups of 6-10 that stand in a line about 6' from the edge of the stage. I usually mic them with 4 mics spread equally across the edge of the stage, but this breaks the 3:1 rule as they are only about 10' apart. I am looking for suggestions on how to improve this layout.
Thanks
Jack

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Does it sound good? What kind of mics? Do you need to phase adjust them to compensate or is it fine? What's the reinforcement, how big, how far away? ..... it's probably fine....
 

FMEng

Well-Known Member
Fight Leukemia
The math behind the 3:1 rule works quite well in the real world, and it informs us that more mics is not always an improvement. Use fewer mics, spread farther apart, or use the four mics with the voices 3 feet from the mics. If you keep the distance from source to mic the same 6 feet, you can accomplish the job with two mics, and it should sound better. It will also give you 3 dB more gain before feedback.
 

jack63ss

Member
We tried 3 mics about 8 feet apart with the singers about 2 feet away for one of the small groups and it did work better. Our issue is not normally with the chorus as a whole, as even with just 50 people they don't need a lot of reinforcement. It is when there is a smaller group (3-6) that it is usually necessary. At some point we'll try 2 mics and see how it goes. Thanks.
 

FMEng

Well-Known Member
Fight Leukemia
It sounds like you are trying to do sound by set and forget. That doesn't work too well with music and a changing setup. That's why sound techs earn their money.
 

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