floor mics

We have some floor mics,and truthfully, I am not at all impressed. Off the top of my head, I am not sure which ones I have (I believe EV), but the gain before feedback is horrible, and being on the floor - the front of the stage is hollow hardwood, there is a lot of low-hum that happens any time any action goes on around them, even with a low-pass filter.
What I tried last musical was to use my three AT853s on boom stands with their stand adapters (love those things), and had the mics about 2-3 feet above the stage pointing at a 45 degree angle. Seemed to work much better than the floors in pick up, lack of feedback, and NOT picking up the pit (the stands were in the pit, which is not really a pit, but just the area in front of the front of the stage.
 
We have some floor mics,and truthfully, I am not at all impressed. Off the top of my head, I am not sure which ones I have (I believe EV), but the gain before feedback is horrible...
Which seems to indicate that it may be the application of the mics, not the mics themselves, that is the problem. Boundary mics still have the same factors of pattern, inverse square law, phasing between mics, etc. that all mics have. Go from a mic being 6" away from a performer's mouth to being 10' away and that's up to 26dB of gain lost regardless of the mic. Push a mic from being back on stage out to the front edge or stage apron and you are probably pushing it more into the house sound system coverage and into the mic's pattern, thus more losses in gain before feedback.

What you often get with mics mounted 2' to 3' above the stage is combfiltering due to reflections off the stage.
 
Good point. I would love to push in the boundary mics further in. Problem is, actors and actresses tend to lose track of where they are. My fear would be a well-placed choreography move would knock one of them right off the stage. They get perilously close to doing that as it.
As far as the other mics, they work better than the alternative.
 
Good point. I would love to push in the boundary mics further in. Problem is, actors and actresses tend to lose track of where they are. My fear would be a well-placed choreography move would knock one of them right off the stage. They get perilously close to doing that as it.
As far as the other mics, they work better than the alternative.

Knocked off stage? Gafftape, man. I don't know about your el cheapo plate mics, but the PCC-160 can be run over a car and still work fine, so I don't know what the problem is.
 
Brad is right on in his quote below. We need to educate sound people about the differences in gain-before-feedback of headworn mics vs. floor mics, just based on the difference in mic'ing distance.

We've found that many schools and churches who do theater cannot afford headworn wireless mics, and the sound operators cannot deal with them effectively. So floor mics are a practical compromise. The laws of physics (such as the PAG/NAG equations) dictate the gain before feedback of any particular mic/speaker system, and these laws suggest various ways to get the reproduced sound as loud as possible given the mic'ing distance of floor mics.

Some ways to optimize the gain-before-feedback of floor mics are:
* Place the loudspeakers closer to the audience than to the microphones. To do that, some schools rent portable PA speakers on stands, and sometimes delay the speakers' signals so that the precedence effect localizes the sound on stage.
* If a speaker must be used over the center of the stage, try to use a line array to reduce the sound radiation down toward the microphones.
* Reduce the number of open microphones (NOM) - turn up only one mic at a time when possible. The more mics that are on, the poorer the clarity and gain before feedback.
* Another way to reduce the NOM is to use one amplifier channel and loudspeaker per microphone. Place the speakers close together.
* Use a graphic equalizer, or automatic feedback suppressor, to notch out frequencies that feed back.
* Place the mics as close to the actors as is practicable. If this creates the problem of the mics being stepped on, use a TM-125C mic which has a permanently attached cable, and no tiny TA3F connector to break.
* Use highly directional mics, such as half-cardioids or half-supercardioids.
* Most important, teach the actors to project! The mics need something to pick up.
:) -- Bruce Bartlett, Bartlett Microphones
Which seems to indicate that it may be the application of the mics, not the mics themselves, that is the problem. Boundary mics still have the same factors of pattern, inverse square law, phasing between mics, etc. that all mics have. Go from a mic being 6" away from a performer's mouth to being 10' away and that's up to 26dB of gain lost regardless of the mic. Push a mic from being back on stage out to the front edge or stage apron and you are probably pushing it more into the house sound system coverage and into the mic's pattern, thus more losses in gain before feedback.

What you often get with mics mounted 2' to 3' above the stage is combfiltering due to reflections off the stage.
 
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While I will not argue with the types of floor mics others have suggested (I am sure they are better than what ever I suggest) one thing we do in our theater to try to stop picking up the pit band is to make some shields (2 pieces of door skin about 4" high, glued at a 90 degree angle and when finished will go around either side of the floor mic). I do believe it helps a little
 
While I will not argue with the types of floor mics others have suggested (I am sure they are better than what ever I suggest) one thing we do in our theater to try to stop picking up the pit band is to make some shields (2 pieces of door skin about 4" high, glued at a 90 degree angle and when finished will go around either side of the floor mic). I do believe it helps a little

Another method that improves rear rejection of floor mics (at least at high frequencies) is to put a 2-foot-square piece of 4" thick acoustic foam behind each microphone. The foam piece lies flat on the stage floor.

In the link below, search for "Baffles Improve PCC Rear Rejection". It's an article I wrote in 1993 that suggests ways to increase the rejection of sounds behind a floor microphone:

http://www.crownaudio.com/pdf/mics/memo22yr.pdf

-- Bruce Bartlett, Bartlett Microphones
 
One tip that I can share is that we place a conduit clamp
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over the point where the connector connects to the mic, and then screw it into the deck. It blocks the fragile connector from being broken off by misplaced feet.
 
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Knocked off stage? Gafftape, man. I don't know about your el cheapo plate mics, but the PCC-160 can be run over a car and still work fine, so I don't know what the problem is.

I have used my aging PCC160s for everything you could think of (mostly for recording) -- from covering multiple acts, to plays, to lecterns, to mounting them on 4x8 (or larger) plywood sheets overhead for reinforcement! I had one chorus' front row break into choreography and actually dance over my Crown's! (whatever happened to "No Surprises for the Production people, huh!" ??) They held up like troopers. I'm now using them to mostly mic table conferences (Public Access TV) and I still love them.

A note to "novices": They have a beautiful pickup "hemisphere" of about 12 ' L/R and about 8' "upstage" with very high rejection at their ass-end. HOWEVER, if your actors stand closer than 3' then they're talking "over" them and they're going to be pretty useless. And yes they do a pretty good job of rejecting the band/orchestra, depending.

I learned about the principal behind the Crowns about 40 years ago, long before I ever heard of them, when boundary mics were called "floaters". I began using directional dynamics on mic stands just in front of the apron, with the elements pointed at the edge of the stage , and at a stand height that put them 3/8" above the deck. No more. Worked like gangbusters for live reinforcement. Even better for recording. Also laid them on foam as has been mentioned above. (still doing that one when the Crowns are busy elsewhere) Then I discovered the Crowns and have been trying them in every situation I could imagine. Someone mentioned inside a piano, and that can work (although I believe the surface area of the lid will negatively affect how the mic handles certain frequencies, which is why I always start with another style of mic pointing up at the bottom of the instrument's soundboard.)

Anyway, my undying gratitude to the gentleman above who designed them (and BTW their original little connectors are still going strong!)
 
...I learned about the principal behind the Crowns about 40 years ago, long before I ever heard of them, when boundary mics were called "floaters". ...
"Floaters" conjures up all sorts of distasteful images. I believe the proper term is "float mics"--floats being the British term for footlights. Before PZM and PCC boundary mics, the mic mouse was used, with limited success.
 
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