Microphones Miking Stage for PA

aferna27

Member
Hey folks,

I'm needing to mic a 65' wide stage, with a depth of 35', with the purpose of feeding the resulting audio into Clearcom's program input and the control booth, dressing rooms, and green room in the venue. My current plan is to mount two PZMs on each side of the proscenium, as I have seen this used in another venue and it worked relatively well:

https://www.sweetwater.com/store/detail/PZM30D--crown-pzm-30d-pressure-zone-microphone

However, this stage is about twice as large, and I'm concerned that this approach won't do a great job at picking up dialogue center stage.

Does this plan seem workable? Any alternative suggestions?

Thanks!
 
Things to keep in mind:

3-to-1 Rule: Area mics generally want to be 3 feet apart for every 1 foot away from the source.

Inverse Square Law

Attached is the Shure Guide to Theatre Microphones.

Also when deciding to use PZM microphones remember how they are designed to be used. They make use of the increased pressure at a fixed boundary to get a nice boost. So you need to install them so they can make use of such a boundary. Somewhere I have the Crown guide to the PZM and PCC, but I can't find it to share with you. Google is your friend. It is a really handy reference when thinking about things like this.

Keep these things in mind.

I agree that often I get better results with "shotgun" microphones pointed at the stage from in front for things like Program, but it doesn't work as well for reinforcement as the mics will much more greatly hear the speakers. But GREAT for monitoring.
Microphone selection depends on location, etc. But generally, a condenser of some sort is used. It can by in an XY setup as suggested above or not depending on the size and shape of the room. For instance in one of my theatres a single Audio Technica
U853PM picks up the entire theatre perfectly well.

EDIT:
I also have a 350 seat venue with a 30' wide pros. that I use 2 mics for, one is in the ceiling of the theatre and the other is on stage. Captures the whole room and provides a really useful program feed.
 

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I've always used a PZM on the underside of the grid on a piece of foam or a 57 on the balcony rail. Dressing room feeds are inherently difficult because you want to be able to hear the SM yell for someone while standing in the house alone and an orchestra and vocals of a concert. What you end up with is alot of room tone.
A tactic I haven't tried yet but heard about relates to assisted listening is have your room mic and a board feed into a 2 channel compressor. Put a 20:1 compression ratio on the room mic but have it triggered by the board feed. What you get is an effective room mic until you have sufficient audio from the board.
 
How are you feeding the theater's assisted listening system? I'd be tempted to try a split of that signal before spending money on PZMs.
 
A tactic I haven't tried yet but heard about relates to assisted listening is have your room mic and a board feed into a 2 channel compressor. Put a 20:1 compression ratio on the room mic but have it triggered by the board feed. What you get is an effective room mic until you have sufficient audio from the board.

That's what we do. I've got a pair of condensers on the bridge in XY and heavy compression on them to feed backstage and our CCTV. It works really well.
 
I've also used the PZM-on-board (2' x 2' was probably foam-core), and 57 on the rail. In at least one of those set-ups I picked up a handful of the RDL "Stick-on" audio tools and put compression and roll-off on the mic. Cleaned it up considerable.

What I question is putting it into coms. My experience is that you want coms clean -- and many of the people on headset are already hearing far too much stage already. We had monitor speakers hung in the booth, and in the dressings rooms. In one rig I worked with for years, the SM's headset had a "broadcast" switch that would send her to the dressing room and mute the stage feed during the announcements.

(Whether to put a volume knob on the speakers is...err...up for discussion. In the booth, yeah, and zoned if possible because some people don't need to hear the stage and some really need to hear it. But for dressing rooms? I've had too many sad experiences with actors getting annoyed that they couldn't do their important socializing, turning down the monitor to a whisper, missing their entrance, then blaming the tech staff because "the monitor wasn't working." The really clever one, though...ripped the wires out. And missed the entrance.)
 
I'm tackling a similar project for the school I am TD for. My design goal has been to provide a high intelligibility feed for assisted listening first and then also have that signal for backstage relay and program feeds to headsets. My approach has been to build up a mix from spaced pair Beyerdynamic 201's on my pipe grid (50' wide by 25' stage with a 17' trim height). They are on short boom arms to swing away from fixtures and be just out of sight. These two signals will be combined with a feed from the sound board and mixed with a Yamaha MTX series install mixer. It has sufficient features manage dynamics and to matrix all the destinations I need. As an added bonus I get to add a paging mic to the booth that links over a cat5 run to the mixer.

The audio testing I've done so far has been very pleasing with a good balance of direct vs reflected sound due to the polar pattern being almost hypercardiod on the 201 and could even serve as a recording feed for us too in a pinch. Our space doesn't do much in the way of everything through the PA type music performances as our music program is rooted in big band jazz the old fashioned way.

Dan
 
one thing to keep in mind - if the distance to actors varies widely between multiple mics you are mixing down for a feed like this, be sure to time-align them to avoid muddiness. If you are using a compressor at 20:1, its probably acting more like an A/B switch, and time alignment is not a concern. But if balcony rail and over-hung mics are both active simultaneously, pay attention. For reference, 50' is approx 46 milliseconds.
 
I'm interested how the 2 condenser mics vs just 1. Understandably in other situations I might want stereo or be able to pickup audio that's more on one side of the room than the other, but no matter the polar pattern of a mic, once it's 30+ feet away from the source, does it really matter?
And totally Ben, I think it is more acting like a switch. Is there like an industrial ducker that could be used instead of my complicated compressor thing? Like a little box that could be buried?
 
I've also used the PZM-on-board (2' x 2' was probably foam-core), and 57 on the rail. In at least one of those set-ups I picked up a handful of the RDL "Stick-on" audio tools and put compression and roll-off on the mic. Cleaned it up considerably.

What I question is putting it into coms. My experience is that you want coms clean -- and many of the people on headset are already hearing far too much stage already. We had monitor speakers hung in the booth, and in the dressings rooms. In one rig I worked with for years, the SM's headset had a "broadcast" switch that would send her to the dressing room and mute the stage feed during the announcements.

(Whether to put a volume knob on the speakers is...err...up for discussion. In the booth, yeah, and zoned if possible because some people don't need to hear the stage and some really need to hear it. But for dressing rooms? I've had too many sad experiences with actors getting annoyed that they couldn't do their important socializing, turning down the monitor to a whisper, missing their entrance, then blaming the tech staff because "the monitor wasn't working." The really clever one, though...ripped the wires out. And missed the entrance.)
@nomuse Speaker attenuators with integral bypass over-ride relays are HIGHLY recommended for attenuators in dressing rooms and green rooms where "talent" tend to turn attenuators to reduced levels ranging from quiet to off / inaudible then forget to turn them up again.

Such attenuators are common for 70 volt systems and I'm told for 25 volt and low impedance applications as well.

Attenuators are available in a range of wattages from a few watts through 50 and 100 watt capacities for applications such as long corridors and / or large rooms with multiple speakers per room.
By pass relays are typically 24 to 30 volts DC and consume very low current per relay.

Tapped autotransformer attenuators are HIGHLY recommended over more "value engineered" potentiometer types:
Higher initial cost per unit but MUCH longer service life with fewer replacements and associated labor costs.
The 'Buy once / cry once' philosophy is extremely applicable to by-passed stepped attenuators.
Good quality stepped autotransformer by-passed attenuators have been known to survive two decades at the hands of 'knob twisters'; Equity, AF of M and non-union alike.

Rigid conduit and junction box covers affixed via "one way" fasteners are your best defense / protection against your "really clever" personnel.
Toodleoo!
Ron Hebbard
 
There are paging system controllers with ducking functions - generally designed for line level 600 ohm (telecom audio) feed -- but their signal/noise ratios are likely very poor, and I can't recall seeing one with > 1 balanced input, unless you get into expensive TOA or Bogen platforms which are empty chassis + add-in modules to roll your own.

If you have a digital audio console and you're not out of channels, carving out an aux buss and a few input channels for this function is probably most cost-effective.

 
My usual route is analog in a service closet with the 70v amp because I don't want someone to accidentally think this compressor is for something it isn't.
Such an annoying thing about audio is depending on what the use case for the audio is determines what "good enough" is.
 
There are paging system controllers with ducking functions - generally designed for line level 600 ohm (telecom audio) feed -- but their signal/noise ratios are likely very poor, and I can't recall seeing one with > 1 balanced input, unless you get into expensive TOA or Bogen platforms which are empty chassis + add-in modules to roll your own.

Rolls makes a few nice little mixers with ducking functions and a handful of balanced inputs, such as the RM67, RM64, and MX153. They may not be quite right the applications being discussed, depending on the specific requirements for gazintas and gazoutas. I've personally used an RM67 in a paging/background audio application, feeding a 70V system in the lobby of a meeting room/auditorium at a camp and conference center, and it's worked out splendidly for that system. Audio quality is quite decent (though that's not to suggest it would be up to, say, modern CD mastering levels).
 
I'm interested how the 2 condenser mics vs just 1. Understandably in other situations I might want stereo or be able to pickup audio that's more on one side of the room than the other, but no matter the polar pattern of a mic, once it's 30+ feet away from the source, does it really matter?

I had two mics is the short answer. The longer one is having a stereo pair makes it easy to throw a band concert onto a flash drive in a hurry without having to do very much extra setup. If we know in advance we're recording we'll obviously do more, but it's a nice ace in the hole for the inevitable, "Oh hey, by the way..."

What I question is putting it into coms. My experience is that you want coms clean
We've injected coms into backstage feed, but not usually the reverse. Each operator station has it's own independently controlled monitoring for that, but usually my kids keep them turned down.
 
Thanks, everyone, for the awesome responses! Always impressed by the wealth of knowledge here on ControlBooth. To answer some questions, here's a bit of clarification:

The venue is a high school theater. Originally, a program feed and the feed to the assistive listening system was provided by six "choir" mics suspended in a grid above the stage. These went into the mixing console, and came out of an aux. When I first became involved with the theater, this solution resulted in an incredibly muddy output, with several dead spots across the stage, thanks in part to the positioning of softgoods and the unique architecture of the space. Today, only half of them are operational, due to them being regularly whacked by ladders during light hangs, focuses, and scenic installations. The stage is incredibly short, with the height of the proscenium being about 12', a 15' electric height, and a uninsulated, metal roof at 20' above stage deck. When it rains, that metal roof did not play nicely with the choir mics at all, and the feed would just become white noise. Additionally, there are no traditional balcony rail positions or catwalks in the space. It's a nightmare for lighting, and I can't see them working for mics.

My options now are to revert back to the previous setup, replacing the microphones with ones that utilize a more appropriate polar pattern and better placement, or start from scratch and come up with something new. From what I've seen suggested here, I think PZM or PCC microphones mounted on the stage floor may be the best solution for the space. They tend to be fairly rugged, are fairly inexpensive on eBay, and do a pretty good job of picking up audio in the space.

A few other excellent points from @nomuse and @RonHebbard :
What I question is putting it into coms. My experience is that you want coms clean -- and many of the people on headset are already hearing far too much stage already.
You bring up a pretty good point. There are four channels of com in the space, so it's possible to remove program audio from the technicians on stage while still having it on for those in the booth, who really can't hear much of anything. Fortunately, with the MS-704, this is one of those things that's easy to try out and see how it works, and switch around as necessary. I have a feeling I may end up just using the 70v system, and not piping program feed into the coms.
Whether to put a volume knob on the speakers is...err...up for discussion. In the booth, yeah, and zoned if possible because some people don't need to hear the stage and some really need to hear it. But for dressing rooms? I've had too many sad experiences with actors getting annoyed that they couldn't do their important socializing, turning down the monitor to a whisper, missing their entrance, then blaming the tech staff because "the monitor wasn't working."
I definitely agree with Ron's suggestion for the relay on the attenuator, and the one-way security screws. I've actually already speced this out based on some of the other posts I've read through. What I'm thinking will work best for the venue is to pass the program feed into the Clearcom MS-704, and bring the Announce output into the 70v amplifier. Combined with the built-in Announce relay on the Clearcom, this should allow the volume to be adjusted in the dressing rooms as necessary, but also force the volume to full and cut out the program feed when paging the dressing rooms from the MS-704.

Admittedly, this still doesn't fix the problem of actors turning the volume down and not hearing their entrances, but it does allow stage management to page the dressing rooms without having to worry about not being heard. If it presents itself as a problem, however, it wouldn't be difficult to add another switch into the relay line to disable the volume controls for the duration of the event.

Again, thanks everyone! You've been a huge help.
 
The venue is a high school theater. Originally, a program feed and the feed to the assistive listening system was provided by six "choir" mics suspended in a grid above the stage. These went into the mixing console, and came out of an aux. When I first became involved with the theater, this solution resulted in an incredibly muddy output, with several dead spots across the stage, thanks in part to the positioning of softgoods and the unique architecture of the space.
That's a classic case of when more mics is not better. The 3 to 1 rule must be obeyed to avoid comb filtering. The 3 to 1 rule is that when there are multiple mics, of equal gain, they should be spaced apart 3 times the distance from the sound source to the closest mic. If an actor's mouth is 6 feet from a mic, the next closest mic should be 18 feet away. This is especially true with miking choirs.
 
That's a classic case of when more mics is not better. The 3 to 1 rule must be obeyed to avoid comb filtering. The 3 to 1 rule is that when there are multiple mics, of equal gain, they should be spaced apart 3 times the distance from the sound source to the closest mic. If an actor's mouth is 6 feet from a mic, the next closest mic should be 18 feet away. This is especially true with miking choirs.
When I do little demonstrations of comb filtering with loudspeakers (more is not better) and everyone finally hears it and 'gets it', I ask them to think backwards, as if the speakers were microphones and what the summation of them would sound like. For the folks that get the Cartoon Lightbulb of Realization glowing over the heads, it's priceless to see the expressions on their faces.

Since this is about *time*, watch the Calendar. I'll be posting entries for Practical Show Tech's episode on Smaart. Also, Smaart publisher, Rational Acoustics has taken the first 2 days of their 3 day paid training and put it up on Yoo of Toob, free. A $600 value, but if you call now... And Rational has extended the time the demo version of Smaart will work full-featured. I've no relationship with Rational, I'm a satisfied user of Smaart and Rational's in-person training (2x). Similar dual channel FFT analyzers like SysTune or even REW can also open your mind to time, and time is distance, and time is frequency, and time is chronology... but once you wrap your head the basic physics of time you'll look at many audio problems very differently. /pimp my time
 
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