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Old May 15th, 2015, 04:17 PM   #16
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Re: Mics for stage

Yep - he did, and he's a nice guy. I even did a parody of one of his videos and he thought it was funny.

The PCC-160 was a standard for theatres (perhaps even still is). Some people say the new ones - the stage and the recording version - are a bit brighter, but personally to my ears, they sound very similar, although the Bartlett design is a little more heavy weight - and a bit smaller. The Stage version is a direct replacement for the old PCC-160. It sounds a little different - but close.

Worth noting that they do a version with a cable gland rather than the mini socket. Standing on these, or in the case of dancers, jumping on them can cause problems when they snap!
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Old May 15th, 2015, 05:10 PM   #17
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Re: Mics for stage

Yeah, I was wondering about the preferred connector. From the website, it sounds like the captive cable version is more robust. I like robustness! I would guess that the connector version would be better for road shows (for breaking down equipment from cables for transport) and the captive version would be preferred for fixed locations.
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Old May 16th, 2015, 10:17 AM   #18
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Re: Mics for stage

I came across this thread, so I put up a sample of the Bartlett TM-125 which I used as a backup stage mic for a shoot last week. This is just one mic on the front lip, no equalization, fed into a Zoom H4N. The risers were almost 20 feet back from the lip of the stage. You can hear a lot of foot noise, and the boy's crying at the end was louder than their singing. I've always been impressed with the Bartlett, even one mic can sound like a complete mix.
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Old May 16th, 2015, 08:57 PM   #19
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Re: Mics for stage

Yeah - they needed to sing louder!!! Not the mic's fault, of course! Piano was fine
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Old May 18th, 2015, 11:25 AM   #20
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Re: Mics for stage

Thanks Warren,

I think the most impressive thing about your recording is the lack of noise at that distance. There are two main reasons for close mic'ing: 1) to isolate the sound, and 2) to get a high signal to noise. Your recording eases my worries about #2. :)
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Old July 23rd, 2015, 01:24 PM   #21
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Re: Mics for stage

Last night, I did the first test of the Bartlett Stage Mic in a church auditorium. The results were mixed and hopefully can be improved.

The space is terribly reverberant. The audience space is about 70 feet long, 35 feet wide and 15 feet tall. All surfaces are parallel and reflective. There is a large beam about 15 feet in front of the stage that gives an additional early reflection.

The stage is about 2.5 feet up with front walls on the left and right, making it's own separate, smaller box (about 20x15x12). It's also reflective, but not as live as the main room.

Speaking loudly from the stage, one can hear a sort of "tuned feedback" even without a soundsystem!

For speakers, we purchased a pair of SRM450v3 powered speakers on stands placed wide and forward of the stage. The Mackies have built-in feedback suppression and we ran them with a flat EQ curve. With that setup, voices on the stage come through, but right at the verge of feedback. In fact, the energy one hears from the speakers tend to be those that excite the room. That's the sound the person speaking from the stage hears as well.

MY PLANNED SOLUTION is to build a "mic screen" in front of the stage mic. In theory, that will "stop" the energy from getting to the mic from the main room. Of course, energy that gets into the stage area can still get to the mic, but the smaller stage would be much cheaper to treat. Also, it doesn't seem to resonate at the same frequencies as the main room.

The "mic screen" needs a combination of isolation and absorption. I can build a hard shell for the audience side and stuff it with absorptive material on the stage side. Heavy wood (like MDF) would be easy to work with. Concrete might be better acoustically, but would be heavy and fragile. I have some 703 panels for a home project and figure that 4-inches of the stuff inside the half-shell, would make it fully dead.

From there, we can see about treating the stage area.

Any thoughts or recommendations?
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Old July 23rd, 2015, 02:59 PM   #22
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Re: Mics for stage

The Bartlett Stage Mic is already cardioid. At best I would expect no improvement in rejection of sound from the rear, and at worst, a barrier may even make it worse by disrupting the back-side pickup pattern.

Frankly using barrier microphones like that for reinforcement is something I wouldn't even attempt. They are OK in some cases for recording. But I have zero expectations they would be useful for reinforcement. Good luck.

Sounds like your room has a natural resonance (your report of "tuned feedback" without the system on).
That means that the room needs NO reinforcement at that frequency, and you should filter out that frequency from the reinforcement system.

It also sounds like you have correctly identified some of the problematic reflective surfaces. I would have spent my budget on acoustic mitigation rather than barrier microphones.
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Old July 23rd, 2015, 05:31 PM   #23
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Re: Mics for stage

Yeah, I knew that this was "challenging". We didn't expect much reinforcement, but we do get a bit. We spent around $200 for the single mic on a 20-foot stage. $200 wouldn't have scratched the surface of the treatment needed in this large space, so I'm happy with the direction we chose.

The speakers have feedback killers, but this room overwhelms them. In my quick living room test, it lit two of four LEDs. In the auditorium, all four are lit. It's maxed out. I could add a 1/3 octave EQ, but I'm afraid that I'd be chasing node after node. Kill one mode, nudge the volume, and the next node will resonate. Rather than starting flat and cutting problems, I'd probably want to start at zero and see which frequencies I can safely add. ;)

I still think the stage mic is our best bet. They will have a gaggle of 4 year olds on stage. Last year, people had problems hearing them. They're short, so they won't be far from the mic. :) Lavs were impractical and way over budget. Hanging mics would be farther from the "younglings" and would still present a feedback issue. A stage mic was our least bad affordable solution. And yes, it does help a bit.

The Mackies were a great choice. We could have stepped up to the 550s, but they weigh twice as much and cost more. The 450s have more than enough grunt and quality for this application - and one person can mount them on stands without injury. The feedback killer isn't a panacea, but it's simple, it helps, and it nearly came for free.

I'll give the mic shield a try. Yeah, the Stage Mic is spec'd as cardioid, but to be honest, I first set it up sideways and couldn't really tell which end was up from sound tests. I then turned the unit over and found the direction arrow. And yes, if the "bad sound" is eliminated from the front but not the back of the stage, I could be killing the cancellation signal while keeping the on-axis signal. Oh well, it won't hurt to try it. I might need to treat the stage to make the mic shield truly effective.

Such is life on a budget. With unlimited funds, we'd have an awesome space, high end lavs and transmitters for all the kids, a professional mixer, and enough wranglers to get the mics on the kids and then back in the equipment vault. For now, we'll made due.
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Old July 24th, 2015, 07:23 AM   #24
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Re: Mics for stage

From my past PA experience, I think it would not hurt you to notch out the worst two or three fixed frequencies. That would free up the adaptive filters on your speakers to work on some other frequencies, which might change from moment to moment.

Also, have you considered adding an outboard feedback eliminator? I had great success with some of the Sabine units. However, an external unit might interact with the adaptive filters in your speakers, so you might need to disable those if you're using something outboard.

And can you at least add a little absorption behind the kids? In other words, add it to the wall that the mic is pointed toward. That might help reduce reflection of the "room sound" off that wall and into the front of the mic.
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Old July 24th, 2015, 10:44 AM   #25
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Re: Mics for stage

I agree with Greg. At a facility where I used to support a lot of meetings in its original configuration, I had to use a Shure external feedback reducer (connected to a computer for full functionality).

I probably achieved only 3 to 4 db more gain using the feedback reducer, but that made the difference between success and terrible sound.

People unfamiliar with this theater would step onstage during load-in and ask that the sound system mics please be turned down! Then I would tell them the sound system wasn't actually on yet... Freakish acoustics!

Over the years they replaced the orchestra pit cover with a much heavier, less resonant set. They added more acoustic treatment to the entire space, and then finally replaced the complete sound system with a much better one.
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Old July 24th, 2015, 11:37 AM   #26
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Re: Mics for stage

I also considered an outboard feedback killer. That might make it into next year's budget, but I sure would want to try-before-buy.

One challenge is that the operators aren't technical. For Drama Camp next month, kids will be operating the mix, which will be four knobs for four sources (handheld solo mic, stage mic, keyboard, PC sound). I need as much as possible to be set-and-forget.

The previous system was very poor for the group. It was a Yamaha kit, including a powered mixer with many knobs and not much power. The speakers were small and underrated. They had already blown a speaker before I came onto the scene. There was no feedback killer. Adding an outboard unit while trying to explain Effects Send and Return wouldn't have worked. The first step after they turned that unit on was for them to say, "somebody get Jon cause I can't get any sound out of this thing." :)

Now, with powered speakers, EQ or an outboard feedback unit would go inline, so it might be more viable.

And yeah, I think the next step is to shield the mic from the front and treat the wall behind the actors. That should reduce the feedback from the hall both straight to the mic and after reflection. Hopefully, we'll get a few more dB of signal with that setup.
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Old July 24th, 2015, 03:35 PM   #27
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Re: Mics for stage

Just come to this again - and actually had (ironically) some shows with exactly this problem.

First thing, forget external feedback killers - to latch their filters onto a problem frequency you need to let the thing feedback. If you can do it in rehearsal, fine, but live, with no prep - they're hopeless. They also cut huge notches into the spectrum and they sound horrible. I have a pile in a rack somewhere that have not been used for maybe six years!

When you push the fader, and start to hear the ringing - if it's one frequency, then a tweak with sweepable eq is as far as you can go, and then that is the maximum that fader can go. This will be very gentle amplification, don't expect real volume.

I did a show with mainly kids and young adults - a dance show on the paperwork, but it was a dance AND song show, and the first time we heard them was the afternoon rehearsal. It took five minutes to put three cardioid boundaries out. One well balanced choir came up in volume nicely. However, all the ones where they really just didn't sing were awful. I could hear feet, I could hear fidgeting sounds but no voices. The organisers complained. Turning down the track they were whispering to made them sing even quieter. Turning it up made them sing a bit more, but the technically un-savvy teachers said it was drowning them out, so down it went again. In the end, I handed out 6 hand held radios and they had to use those. They damaged two!

There is no magic solution. Set and forget doesn't exist. You can get some conference systems that are very close to this but for shows, forget it. Unskilled performers and unskilled operators = disaster.

I felt sorry for a PA company who put in a 12 channel radio system for the school end of course show. The teachers got them to set it up, do the eq with the kids, and then they went. Instant bedlam - swearing from the dressing rooms, incessant feedback, totally awful mix. I was actually playing in the band and they panicked and asked me what they should do. I suggested they pay the guy from the PA company to work it for them. They could not see why they had to do this - after all, it was professional equipment and expensive to hire. I played, ignored the train wreck and went home. I would strongly advise NOT trying to shield the mic from the audience, you will wreck the way the boundary mic works. It relies on being on the big surface for it's gain and performance. A reflector behind it will make it even more prone to feedback. I built a housing to protect people from fallout from pyro pods, and it lowered the gain available from the boundary mic next door.

If the performers really don't produce much sound, then the mics will hear whatever is loudest, and this will be what you DON'T want to amplify.

With boundary mics, there is no point in a mega PA, because the gain before feedback won't even tickle it.

Stick a mic on somebody, or in front of somebody and the ratio between wanted and unwanted sound gets better. Any distant microphone of any kind is at a disadvantage, because it cannot select wanted from unwanted sound sources, it will hear whatever is there. Sadly, to get volume costs lots of money if the performers are the weak link.

Oh - and I broke one of the mini-XLRs after saying how good they were. I climbed down a ladder and my heel landed right on it. It didn;t break the mic socket, but snapped off the connector completely - leaving it in the socket!
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Old July 24th, 2015, 04:19 PM   #28
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Re: Mics for stage

Great post, Paul. Nothing like practical experience!

Yeah, there are no silver bullets. I'll do as best as I can.

Regarding the boundary mic, I had it placed not far from the edge of the stage. Should I have moved it back? Is there a guideline for placement? Do we know what to expect as we move it from edge to center of the stage? If the shield is really dead (MDF + 4-inches of 703 fiberglass) and right at the lip of the stage, I'm not sure that it would impact the boundary effect.

One nice thing is that the stage surface is linoleum on concrete. It's solid and won't pick up creaking wood or resonant footsteps. Of course, we'll still get clothing noises and other rustling.

Note that we have a handheld cardioid for announcers and soloists, so we aren't totally dependent on the floor mic. It's an old Audio Technica that I bought 30 years ago and donated, along with a cheap Behringer mixer. I was worried that the mixer might add too much noise at high gains, but it hasn't been a problem at all. The Bartlett Stage Mic has a nice, strong output. I get feedback far before the noise is annoying.

Regarding the feedback destroyer, it's not terrible in this situation. Of course, it affects all sources, including music playback. Yeah, music sounded a bit funny, but the color from the destroyer is secondary to the color from the room. For our application, I'm reasonably happy with the results. It's no magic fix, but it helps more than it hurts.

This is a casual gig. Kids practice drama for a week in the summer. At the end of the week, parents and active church members attend the "big show". There are no curtains and no dramatic lights. Expectations are not high. But it's fun for the kids and heartwarming for the adults and their camera phones. There will be about 50-60 in the audience.

I think the system will give a bit of improvement from last year's "unplugged" event. Every dB helps. And it will be an opportunity to talk about the need for room treatment for the next budget cycle.
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Old July 24th, 2015, 04:55 PM   #29
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Re: Mics for stage

The stage we were using had a solid cover over the orchestra pit - nobody seemed to be actually dancing or standing on it, so we pushed the mics onto the edge of the 'real' stage, and gaffer taped them there, with cables going forwards to the stage edge. The problem with the barrier is simply that it produces a reflection from the sound source that arrives fractionally late and you get a comb filtering effect, that not only colours the sound, but creates peaks and troughs in the frequency response - making feedback worse. The PCCs are less sensitive at the rear, of course, which helps, but if you listen to them on PFL you can definitely hear the audience, although at reduced level. Sound from upstage, hitting the upright you use, adds to the stage pickup but not in a predictable way. We have tried PZM, PCC, short shotguns, flown omni and cardioids and none give you volume. On our stage we would use 3 or 5 PCCs, simply so one is always in the middle. If you bring up the centre one to just below feedback point, as soon as you add in the ones next door, the centre one has to come down, reducing it's level, add in the outer two and the others come down yet again. If you have one person centre, you can squeeze a bit more by taking the others out, but if it's a group of people spread across, then you just don't have the gain before feedback. Trying to mix these is an operational nightmare if you need every last dB. If the sound op has other stuff to do, then the only sensible operation is to find safe places for the faders and forget them
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Old July 24th, 2015, 05:43 PM   #30
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Re: Mics for stage

W/O re-reading the thread, where are the PA cabs located? That can make a huge difference in feedback.
For the recording (if there is one), I recommend feeding the recorder with a pre or post fader send so cranking it for optimum record levels, would affect the house volume.
Yes indeed, Paul's reply is right on. +11
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