# Comb Filtering



## Schniapereli (Jan 4, 2007)

I just entered High School, and became sound guy, and am having a little trouble getting used to the better actors. They act a lot closer to eachother, thus causing comb filtering, and sounds bad. The play we did was Darn Yankees, which has a lot of different romances from Joe to Lola and Meg, where they get close, and talk, then walk away, then get close, and back and forth a lot. Our Applegate also liked to talk to people with his nose resting on their foreheads. (...not really)

Anyways, what is the best way to deal with these phase cancellations? When they are close together for a long time, I can easily just turn one down, but what do you do if they keep moving around a lot? Do you just get better at moving one mic up and down accordingly? I have heard of just moving the gain instead, but that would mess up the level where I want it. Is there some ancient Chinese technique I have never heard of?


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## BNBSound (Jan 4, 2007)

Without knowing your rig I'd say that understanding and judiciously using compressors (ie: on the groups) could be a help. But the key issue here is gain. You need to absolutely perfectly nail the gain structure on every channel, trim the EQ within an inch of its life, and then commit the show to memory and work the faders. The good news is, to avoid comb filtering you don't need to take one of the mics all the way out, just drop it down some.


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## Schniapereli (Jan 4, 2007)

I don't take the mics down all the way... but I have a hard time being able to bring the sliders back up to the unison without looking. I watch the actors to tell when to adjust, and my fingers don't move it as much as I think they do. I'm still getting used to the board...

We have 1 compressor/expander with 2 channels. (Behringer autocom pro mdx 1400)
We haven't had them hooked up yet, due to cable shortage, but we will the next play. We don't currently have insert cables, and might not get any, so it will probably be just a sound path from mixer to compressor, to graphic equalizer, to amps.
One sound guy told me it's probably good to put boys on one channel, and girls on the other. But, how do you adjust the settings to eliminate the cancellations?

I will also know the script better for the next play. Last play I was asked to do sound 1 week before opening, (at the begining of tech rehearsal), and then I got my script the night before opening day. (1 tech/dress rehearsal to mark all the added and deleted scenes) But, the next play will be better organized.


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## kovacika (Jan 4, 2007)

Really for compression its best to do one person per channel. Since you dont have too many compressors, you might just want to do leads.(joe, lola, devil)
I also second BNB Sound on the Gain. Gain is everything in sound. Get gain right and your at least half way if not more to sounding good.


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## mbenonis (Jan 4, 2007)

Compressors won't help specifically with comb filtering, but they do help with the overall sound of the show by preventing loud peaks.

It sounds like you're doing exactly what you need to be doing - ducking one of the two actors when they get close. You'll get better at it as time goes on. It just takes practice, like everything else!

What console are you using, by the way? Also, how are your wireless mics performing?


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## SHARYNF (Jan 4, 2007)

Couple of thouhts
What mics are you using? have you looked at mic placement, since you seem to be on a restricted budget, I am assuming you are using some sort of lavalier mic, so one thing to do is to turn the mic so that it is facing DOWN on the person instead of the usual up position, this will still pick up the speaker but may give you a bit more control.

what mixer are you using, do you have the ability to assign the input to an aux? 
you could look at grouping the mics giving your self more control, but you would then need to re combine them to feed your amps.

Here is an example where a digital mixer would allow for more control. 

Sharyn


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## Schniapereli (Jan 4, 2007)

We have MKE-2 Lavs (sweet) with Sony wireless wrt 805 transmitters, and we also have a few Shure SLX 2 transmitters (with their own SHURE 93 lavs). Our board is a Mackie SR 32-4 VLZ Pro.
(EDIT= we mount all of our lavs on the face over the ear.)
Should I just hook up the compressors to 2 different submasters so Or would this be better with the aux sends, and just taking the channel out of the main mix, thus sending it only through the aux sends to the compressor, then into aux returns (or another channel).

Also, how does the compressor help me with comb filtering? How does it react differently from when they are close together, and when they are not? (if at all)


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## CURLS (Jan 4, 2007)

i remember when i was your age and asked myself this ?

My solutions at the time were the same mentioned, just simply fade out one mic a lil bit. You don't necessarily have to take it all the way out of the mix usually 3 to 6 db is all you need since your audience will precieve a 3db boost between both the mics compared to comb filtering.

Unfortunately your particular console does not do this. Another common trick in the basket of goodies is phase reversing one of the mic channels as the actor comes closer to the other actor. 

One other quick thought is considering your using MKE2's HECK YEA. You might want to try figuring out which works better you use the same way I do. If you mount one on one side of an actors face and then another one on the other side of the actresses face sometimes the distance and facial features can reduce the cancellation of noticable frequencies.

Hope this helps!


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## mbenonis (Jan 4, 2007)

Schniapereli said:


> Also, how does the compressor help me with comb filtering? How does it react differently from when they are close together, and when they are not? (if at all)


See my post above.


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## Schniapereli (Jan 4, 2007)

mbenonis said:


> See my post above.


...missed that...

But, just wondering, what does phase reversing do to the signal? Is that what broadway does?

Also what do you mean by "You need to absolutely perfectly nail the gain structure on every channel, trim the EQ within an inch of its life." -BNBSound


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## SHARYNF (Jan 4, 2007)

those are great mics, but the placement of them can be an art based on the performance of the various actors.

the problem with the cheek mounting is that when the two people face one another the opposite person is facing and talking directly in to the other mic. 
Since they are cheek placed it tends to be quite direct.

These are omni mics also 

I would guess that this is more of the problem you are having than actual comb filtering . All these terms tend to be a bit misused, so rather than try to re explain, take a look at http://www.moultonlabs.com/index.php/more/about_comb_filtering_phase_shift_and_polarity_reversal/

You might try different placements
One is on the forehead pointing down, the other is higher up on the temple in the hair instead of on the cheek. 

You might also try to determine if it is just one actor, or a specific pair etc.

In addition these mics are well know for getting problems from sweat, and after getting sweated on, and drying the performance tends to vary also. It is important also to make sure if you can that beads of sweat are not getting directly into the mic. Sennheiser made a gold dot version vs the red dot version to try to help in this area.

Again these are great mics, but not properly used or formerly abused you can have all sorts of problems.

This is where on a large format console VCA's come in handy, where you can assign the level control to a common slider so that you can group the inputs together but still leave the assigned to the same output

Here are a few suggestion that you could do with your mackie

One is make sure that you are running FOH in mono mode, with what you have stereo pa is not a good Idea. If need be you can take the INPUTS to the rest of your system amps etc, and get a y cable and connect it to the mono out of the mackie.

Now on each input you have the ability to select sub 1-2 3-4 and l-r
you can place a pic either on 1-2 or 3-4 of l-r based on the pan knob, so now you have 6 channels that you can sort of work with. Take the sub 1-4 and plug them into your 29 30 31 32 inputs and assign these just to l/r, now what you have is the ability to
group your inputs into 6, L-r are for mics that you assign and typically do not need to alter as a group, the set and forget except for individual channel tweaking, the mics that you do need to control can then via the sub assigns and the pans be split into 4 with now 4 faders controlling these 4 groups. Set your master for your over all level, set the faders on 29-32 for the relative level to the rest of the board, and use the faders for subs as your grouping controls.

This gives you in effect a second level of control on the board, where you can set individual levels, but at the same time move a single fader and control a group as part of the overall mix

Probably sounds more complex that it is but if you sit infront of the mackie and think about it and look at the gain structure you will see what I mean

Sharyn


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## soundman1024 (Jan 4, 2007)

I fight this nearly daily at the TV station during interviews. Typically I take one mic down about 2dB and the person talking's mic up around 2-3dB. Maybe not quite that much. As soon as the person talking turns their head (or moves in your case) I can restore things to where I had them.
Best thing you can do is ride the faders I would say.


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## mbenonis (Jan 4, 2007)

soundman1024 said:


> I fight this nearly daily at the TV station during interviews. Typically I take one mic down about 2dB and the person talking's mic up around 2-3dB. Maybe not quite that much. As soon as the person talking turns their head (or moves in your case) I can restore things to where I had them.
> Best thing you can do is ride the faders I would say.



I dealt with the same issue over the summer, when I worked at the local TV station doing sound for a few shows. They had WL93 mics (wired) and it was so difficult to get one person clearly without them leaking into the other mic - I ended up gating them very closely and riding the faders as necessary.


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## audioslavematt (Jan 4, 2007)

Schniapereli said:


> ...missed that...
> But, just wondering, what does phase reversing do to the signal? Is that what broadway does?



I won't go into all the details of the physics involved, there are plenty of books and articles to be found through google. Essentially, when you "flip the phase" you're really flipping the polarity (so pin 3 becomes hot instead of pin 2). Flipping the polarity simply rotates the phase 180 degrees, reversing it. If you need a visual, graph y = sin (x). This is your normal sine wave. To show the sine wave with the flipped polarity, graph y = -sin (x). Dave Rat himself does a better job explaining it than me. http://www.prosoundweb.com/live/articles/daverat/polarity.shtml


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## Schniapereli (Jan 7, 2007)

This phase switching thing still confuses me a little. I understand the articles, and how it could help with drums, and similar situations, but I don't see how it eliminates comb filtering. I attatched a drawing to show you how I understand it so far.

The middle wave is the original person's voice picking up on another person's mic, and is slightly delayed. The top line is the original person's mic, and the bottom is the original person's mic inverted.

I could see how this would work if it was exactly 180* off, but if they are just a little off, I don't see how phase reversing would help. They still look like they would cancel out. 

And mathematically speaking, it doesn't make any sense to me either. (that reversing it still keeps it a fraction of pi off from synchronization with the delayed version. Inverted is only in a sense moving it forward 1/2 pi, so the nubers are still ugly in between)

What is wrong with my drawing and/or theory behind it?

Is there maybe another site or another good article?

(the wavelenghts are marked at the half to help with my crappy drawing.)


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## Peter (Jan 7, 2007)

Although this isnt really an answer to your last question, it is another idea about how you can improve things.

*If* your venue is setup with a stereo sound system you can try panning the two mics causing trouble to either side so they are separated. It doesn't have to be a complete pan, but play with various amounts, and make sure they can both still be heard from (nearly) everywhere in the house [you may have to sacrifice a handful of seats for the greater good of everyone in this case]. What you are doing in this case is greatly reducing the chance of comb filtering on the pickup (mic) end of things and just tweaking the comb filtering that is already happening to some degree on the output side of your system. 

For everyone doing bands, this technique also works really well for cymbal overheads which can be panned rather hard to either side in a good stereo PA system.


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## CURLS (Jan 7, 2007)

Ok so let me just say this there are very few systems in the world where you will not experience comb filtering to some degree. The least of these being outside where i like to work, instead of a theatre. And also a side note on trying to rid of comb filtering, I would be willing to note that most of your stationary seated audience do not even precieve what is happening with such said comb filtering, but that is audience psychology and not the topic at hand. 

Ok, so when I first made the comment about phase I did not intend for you to misunderstand that it could correct comb filtering. Comb filtering is usually corrected by time alignment.

After I reviewed your initial question I noticed you were merely talking about two actors getting closer to each other thus the combining of two signals results in a positive 3db gain increase. 
Comb filtering results from 2 out of time signals processed by the ear. With that being said a delayed underbalcony fill system out of time with mains would have comb filtering that most people would agree to notice. 

So therefore two microphones that are not in time which is your example are then added to create a single wave that has an increase of 3db that has been shifted in phase based on the distance of the actors that will in turn go through your pa as one single signal. Or multiple delayed systems as still one single signal.

Now to talk about the phase button that I talked about pressing. Your drawing was soewhat correct. But I'll do my bes to explain.
Performer A emmits single sine wave 1k frequency at 3db
Performer A also emits this into Performer B's mic.
End resultant is a 3db increase through performer B's mic at 6db

If Performer A does the same exact thing 
But, Performer B's mic is reversed in phase then 0db of gain is resulted and he remainsat 3db constant gain. This will only work if the reversed phase mic comes in consitent contact with a non reverse phasd mic. So in other words press it when you know two people are coming together.

Or in super simplicity just fader juggle the two leads like the firs reponse ya got and you will be in businss. Happy MIXING!!


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## Andy_Leviss (Jan 8, 2007)

> This phase switching thing still confuses me a little. I understand the articles, and how it could help with drums, and similar situations, but I don't see how it eliminates comb filtering.



The short answer is, it doesn't. It's an audio myth. If your actors emitted pure sine waves, and they were physically spaced exactly a wavelength apart, it would help keep the comb-filtering from happening, although you'd still experience a doubling in level.

The way to solve the problem, as noted above, is to work with mic placement, blocking, and--this is the biggest key--actively mixing and choosing which of the mics will give you the best compromise at any one moment, but only having one up at a time. It's not easy, for sure, but it works.

The other way, which is well beyond your means equipment-wise, is to use an A-B speaker system, and there's even some argument about whether that actually works well.


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## Andy_Leviss (Jan 8, 2007)

To further clarify things, you reverse the polarity on things like bottom mics on drums to keep them in the same polarity as the top mics (or on the mic inside a kick drum, which is technically a bottom mic). Otherwise, for example. if you've double-miced a snare, when you hit the snare, the two mics will be pulling/pushing in opposite directions and will--to some extent--cancel each other out. It's not a matter of comb filtering in that case.

Polarity reversals fix opposing polarities; delays fix phase issues (which manifest themselves as comb filters).


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## Schniapereli (Jan 8, 2007)

okidoki.


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## jkowtko (Jan 10, 2007)

I could use some suggestions here as well.

We wear our lavs over the ear as well. What I've tried that seems to help is to have everyone put their lav over the same ear so when they're facing each other or facing in the same direction, the mics are a comfortable distance from each other and in a "balanced" position.

If you have enough clout, you may also want to work with the director on actors' head positioning and distance. I'm going to start doing that in future shows.

I also play with the faders a lot, and for that you just have to memorize the dialogue.

Fyi, I also think having good lavs helps. We have Countryman B3s for the leads and they seem much better at handling sound issues than the stock AKG C417/Ls that came with our transmitters (AKG WMS80 systems).

I would like to hear if anyone knows what the pros do ... process the sound, or just do what we're doing?

Thanks. John


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## Andy_Leviss (Jan 10, 2007)

LOL, the pro's do the same thing you're doing...we mix. 

Seriously, "varsity" mixing for theatre is all about line-by-line mixing. It's not easy, by any means, but it can be done. I've finally gotten to a point where, if I spend enough time prepping with the script and music beforehand, I can pick up a show pretty fast. I mixed a reading for the NY Musical Theatre Festival with a 12 person cast. As it was a reading, we tech'd lights starting around 9a, and had enough time for exactly one run-through before the 3pm opening performance. Two shows that night, and one or two the next day (can't recall for sure). 

By the second show, I had it pretty clean, and by the third, I was mixing it line-by-line almost in its entirety. It's just about learning your material, learning your tools, and practice coordinating what you're hearing, what you're seeing in the script and onstage, and how your fingers are moving.

The biggest trick in "the big leagues" is that we make extensive use of VCA assignment automation. We mix the show on the VCAs, not the channels. Typically the furthest right two VCAs are the band and vocal reverbs, then the third from last is the band mix (typically your right pinky lives on that fader, for all intents and purposes). Then the remaining VCAs are assigned, as needed, to the actors. In smaller scenes, each actor may have their own VCA. In larger scenes, leads will have their own, and then the ensemble may be condensed onto one or two VCAs. This way you can easily control a large number of inputs with your eight fingers.

But seriously, beyond that, there's no magic, no secret, no processing. It's exactly what you're doing, just with the speed and skill that comes with lots of practice.


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## jkowtko (Jan 12, 2007)

Thanks Andy -- this is great information. I have a few followup questions for you:

1) Mic placement -- in musical theatre, where do they hide the mics? I've seen Disney put them on the top of the forehead pointing downward, which would work if you have wigs or a costume person with the right equipment (glue?) to mount and unmount the equipment on the actors. Beach Blanket supposedly just uses clip-ons, although I wonder how you get consistent sound as the actor turns their head if the mic isn't actually mounted somewhere on their head. At our theater we just tape over the ear, which serves us reasonably well with lack of sound help backstage. Is there a "best" approach?

2) Actor placement -- Are the actors trained and blocked to accomodate sound issues? I.e. do they keep their distance and/or pay attention to head placement during close-ups, etc? I just want to know how much clout I should have in "directing" the play.

3) Sound processing -- In addition to playing the faders, is any sound processing used to help eliminating cross-pickup of mics? Gating?

Thanks in advance. I'm an engineer by schooling but relatively new to this industry so I'm trying to get up to speed on the technology use here ... 

-- John


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## SHARYNF (Jan 12, 2007)

Taped to forehead is pretty common, clipped on most people point the mic down to the chest, then it is picking up the sound with less directional effect

Sharyn


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## Schniapereli (Jan 13, 2007)

Somewhat related questions to what he said. I have seen some Wicked clips from Youtube how they bring down the mic onto the middle of the forehead. I saw a few songs at different places.

1. Do the mikes come with a lot of different colors (except green)? I mean, what kind of color variety do the manufacturers offer, or do they color them themselves.

2. On wicked, it looked like Elphaba's mic was black. Coudn't they special order some green ones? ...I mean, they're Broadway...

3. My dad tells me that a tech told him that the best place for a mic is between the eyes (where the unibrow is on most actors) because of the sinuses vibrating. Is this true? I did not see them like that on wicked. Is it just harder to hide?...

4. Is this why Broadway uses straight forward face lights as oposed to McCandless' version of 45* angles. Is it to hide their microphones better?(no shadow, so they just match the color?) I could only see them when the camera angle changed to a view point higher, or more to the side than the audience sees. (I could see the shadow)

5. Do they glue the mic down, or tape it? (could not see tape)

6. I have heard other places that they store their mics in an airtight box with water absorbant packets. We currently hang the mic upside down with the connector end between 2 screws in the wall. The cords had been coiled with the packs before, and this was supposed to help straighten them out. It hasn't worked very well so far. Do they coil them up in the boxes, or do they get really long and straight boxes? (if they really do that) Is our method of storing lavs upside down on a wall a good system?

7. When miked over the ear, I heard they should be about 2 cm past the ear. Is this true? We have always put ours more forward. We have MKE2's but they are black, so could they pick up well and still be well hidden?

Other random questions.

7.5 How good is the SM58 Shure microphone? I think I have seen it on TV being used for bands, and I think I saw some also being used for violins on an orchestra.

8. What are other good mics for other miking situations.

9. We also have an SM58, which the singers like to keep very close to their mouths. I have seen lips actually touching the grill on TV, but it still had good sound.(and the manual says optimal performance is from 6'' to touching the lips) Our mic still has a lot of P's, B's, breathing, etc. What is used to professionally fix this? Can this be achieved with 1 graphic EQ, and a compressor?

10. Whenever I see miked drums (like on SNL, or other bands) it looks like the mics about the toms are similar to instrument mics, and they are pointing horizontally instead of down. Does this create better sound, or are they omni, or is the cardioid pattern off axis? Or is it something else? (have I just never seen it right?)


I know this is a lot of questions, especially at once. If ya'll kuld jus give your opinion on as many as you could, that would be groovy.


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## CURLS (Jan 13, 2007)

This is the most simplist response, of the one's i know the awnswers too!

1. standard colors are usually black and flesh colored
2. dont know... but cant they have scenic paint them green? broadway= $
3. above the head is standard now a days... however most will agree that every bit of your audio system can say different
4. 30' rule + audience psychology = your not paying attention to the show
5. the ones ive seen have been clipped to the hair line
6. airtight boxes sound cool.. the way you do it is cool.. wrapping them around transmitters or in tight coils at that guage..prolly not soo cool.. 
7. i found that right where the uper jaw and lower jaw meet is a great place... too close to the mouth will result in low end gurgle and too close to the ear and you will delayed swirling of sound passing around and through your ear shape if that makes ne sense.. MKE 2's are badass you shouldnt have many problems!!!! 
7.5 sm58 =.... well best industry wide all in one standard do it mic.. period end of quote. no rebuttle necessarry
8. 52 kik, 421 lots, 91 cool!, 81 killers!, the list goes on!!! only experience will lead YOU to decide what YOU like best!!!
9. High Pass Filter, if ya wanna get fancy sure do the graphic eq plus comp thing.. or just a manley voxbox while your at it.. but then again if your talking about most rock concerts.. having an artists lips touching the windscreen and get where the shure brothers say they perform is the least of anyone in the worlds worries!!!
10. hmm this intrests me if your really correct.. now a lot of times folks will off axis 98's to a 45 degrees or more but yes to awnswer the other question most the time tom mics are directional.. or for that matter very few rock concert mics are omni

hope that helps without being to straightforward


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## jonhirsh (Jan 13, 2007)

"Darn Yankees"

Did they change the name of the show while i wasnt looking?

JH


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## Peter (Jan 13, 2007)

To clarify number 10 abit... It is often suggested that the mic on a Tom or Snare be aimed towards the middle of the drum, and often as far as 3/4 of the way across the drum. Aiming right down at the edge where you have the mic cliped can often lead to a much higher pitched sound then is desired. Drums make different sounds depending on where the drummer hits the drum, and you want to pick up those different sounds evenly, so you generally try to pickup the whole head as much as possible. 


Another thing I just read about in a recording book but have not had a chance to try is this: With a snare drum line up the microphone with the beads (if the beads are running from top to bottom relative to the drummer, put your mic right at the top and aim it right down at the drum edge nearest the drummer) so you get the sound of the beads across the whole head instead of just the sound of the beads where they cross the "streight line of sight" of the mic.

In short, there's no lack of methods to try!


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## Schniapereli (Jan 13, 2007)

I don't understand some of your answers...

"1. standard is 2 colors of lav."
the Countryman line says they have 5 colors. Is this the only company that does this? Do they just use makeup to match the lav to the skin? (or skin to lav color?)

"3. Above the head=standard mic placement..."
...sorry, what do you mean? Not brought down the forehead, but just at the edge of the hairline? 

Also, what is the professional opinion of my dad's sinuses theory? Is this just impractical to hide, or is the sound crappy as well?

"4. 30' rule = audience psychology. You're not paying attention to the show."
...what do you mean?... Most audience members aren't looking for the microphone? What is this 30' rule you speak of?

"5. ...mics clipped down hariline..."
When I saw them (on Wicked at least) the actual head of the mic was 3 inches down their forehead. Do they do this more often, or just at the edge of the hairline (I have seen some very old pictures with them like this from Les Mis, etc.) If it is brought down to the center of the forehead, _then_ do they glue them?

"7. Where upper jaw meets lower jaw..."
Why does the countryman E6i go to almost the corner of the mouth?
(if anynody here is by chance LDS, or has just seen General Conference, is this what they used on President Faust ever since he has been speaking in a chair instead of the pulpit because he can't stand that long anymore?)
I have heard that mic (or, if it is not that one, one just like it) work pretty well, but it disregards everything I have learned about lav placement... Is it just ok becuase it is a stiff cable that supports itself, and is not getting mushy sound from being against the cheek?

Another random one- What is this XLRM type cable I have read about on Audio Technica web site? I read somehwere else that it is just longer? (found this name reading about one of their boundary microphones)

Thanks for your cooperation with the peons.


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## CURLS (Jan 13, 2007)

1. dont know for sure 
3. usually its the hair line.. bringing it down the forehead would probably achieve more gain.. but not sure what to say about the sinus theory thing
4. exactly! 30' rule applies to a lot of things it basically states anything that will be 30' away (distance from audience to stage) should be looked at with a grain of salt.. kinda the whole well jimmmy said we knicked the door jam with that table last nite you go look at it and its the size of less than a quarter chances are your audience wont even notice b/c its soo far away.. dude have you not heard of the 30' rule when it comes to women!? and yes if your audience is looking at microphones on actors heads that far away there not paying attention to the show and the actors should improve!
5. dont know
6. i dont know exactly what conuntryman was thinking when they made the e6.. but if i had to guess they put it closer to the mouth so that no matter who is using it based on the geometry of soo many peoples faces it would land semi close to the mouth and you could adjust it from there where as if it landed around the cheeck you would have a lot more problems... but then again i dont like the way that sounds to begin with but hey thats just me... ohhh and its not a stiff cable that supports it its more like rigid silicone almost 
random nother one.. dont look too far into it.. xlrm pretty much stands for exchanging line reciever male.. although im sure i will be rebuted over 5 times on that one

hey dont sweat it man i remember when i had tons and tons of questions and didnt understand nothin thats what the learning process is all about.. have fun but remember sometimes you can find out the awnswers online its full of information that i dont even understand!!!

later dude keeep rockin!!1


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## SHARYNF (Jan 13, 2007)

down on the forehead, it is infact pointing a the sinus area between the eyebrows, so your dad is correct, and that is why it is done that way, the pickup area on the mic will be right there where he is suggesting

why the e6 is long, various sound designers use different places for the mic on the side of the head and sometimes this mic is used for other than theatrical, so sometimes for singing you might want to get it down closer to the mouth
Sharyn


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## kovacika (Jan 14, 2007)

As for #6, ive never seen sealed boxes, but I have seen condoms. The touring Chicago uses condoms to protect their mic transmitters (sennheiser sk5012's) from actors sweat.


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## jonhirsh (Jan 14, 2007)

Make sure they are un lubricated.

JH


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## Chris15 (Jan 14, 2007)

To me the concept of placing mics in an airtight container with silica gel or some other absorbent material sounds not unreasonable. If I have the theory right, then what it would do would be try out the element of the mic. Having seen how saliva can corrode a conventional sort of mic, then I imagine that there would be potential for a similar sort of effect on lapel mics. By taking away the moisture, I would think it should reduce those effects.


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## jkowtko (Jan 14, 2007)

Mikes close to mouth -- I'm pretty sure this is simply to maximize the difference in volume between the wearer of the mike and all other ambient sound. The E6 are all lower gain (w5-w7 models ... higher number means lower gain) than the B3 (w4, w5), so putting the mike head close to your mouth lets you turn the gain way down and just pick up the one person.

I've seen that they use E6 at tradeshows when the demo person wants to be heard clearly, but you don't want to pick up someone shouting from 3 feet away.


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## Andy_Leviss (Jan 14, 2007)

SHARYNF said:


> Taped to forehead is pretty common, clipped on most people point the mic down to the chest, then it is picking up the sound with less directional effect
> Sharyn



Just one quick correction here--the mic elements typically used for this type of placement are omnidirectional, so you don't need to worry about which way they're pointing. Pointing them downwards is more a way of getting the element a bit closer to the mouth (ie, below the line of the cable/elastic if you're using an elastic loop, or "halo" rig, see my post to follow shortly), not a directional thing.

--A


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## Andy_Leviss (Jan 14, 2007)

Wow, lots of questions, let's see...


jkowtko said:


> Thanks Andy -- this is great information. I have a few followup questions for you:
> 1) Mic placement -- in musical theatre, where do they hide the mics? I've seen Disney put them on the top of the forehead pointing downward, which would work if you have wigs or a costume person with the right equipment (glue?) to mount and unmount the equipment on the actors. Beach Blanket supposedly just uses clip-ons, although I wonder how you get consistent sound as the actor turns their head if the mic isn't actually mounted somewhere on their head. At our theater we just tape over the ear, which serves us reasonably well with lack of sound help backstage. Is there a "best" approach?



Well, this is definitely the month to ask this question, as two magazines happen to have features on just this question! First, this month's _Dramatics_ has an article by yours truly, aimed at users without too much sound experience, which you can read online at: http://edta.org/pdf_archive/unwired_sound81200774727.pdf

Second, _Stage Directions_ has a much more detailed version (for reasons of limitations on the audience and length of my article, I don't go into over-the-ear rigs, other than a brief mention of why they're less desirable), by Jason Pritchard, the head of audio for the Cirque du Soleil/Beatles show _Love_ (not to mention an all around cool and very smart guy). While Jason's article is on the SD website, they left out the pictures, eek! You can find the original article it was based on, complete with photos, however, at Jason's website: http://www.brightandloud.com/microphone-placement/


> 2) Actor placement -- Are the actors trained and blocked to accomodate sound issues? I.e. do they keep their distance and/or pay attention to head placement during close-ups, etc? I just want to know how much clout I should have in "directing" the play.



In an ideal world, they would be. In reality, sometimes if there's a true problem and it's a director who cares a lot about sound, they'll work with you. Most of the time, though, it's up to us to deal with what curveballs the other production departments throw us, through tweaking mic placement, mixing skills, or just dealing with the fact that a certain 3 second segment might sound less than optimal (much as we try to avoid that). There are certainly ways departments work together, for example wardrobe can lend a hand by working with you on the size of a hat brim, or putting some sort of material (like felt) on a large brim to help tame reflections, that sort of thing.

Actually, on that subject, one of the best pieces of advice I was ever given is that the wardrobe department is the sound guy's best friend. Make nice with them as early on as you can, and they'll make your life a thousand times easier in oh so many ways.


> 3) Sound processing -- In addition to playing the faders, is any sound processing used to help eliminating cross-pickup of mics? Gating?
> Thanks in advance. I'm an engineer by schooling but relatively new to this industry so I'm trying to get up to speed on the technology use here ...



Nope. Nothing. Nada. Part of the key to the natural style that most theatrical designers/engineers aim for is minimal processing. It's a bit of a cliche in the industry that, when asked why he doesn't have any compressors in his front of house rack, a good theatrical engineer says, "I've got ten of them, right here," whilst wiggling his fingers.

Occasionally a _light_ bit of compression will be used to tame a particularly dynamic and unpredictable actor, but in most cases, it's really a matter of just learning your script and learning your cast. Once you know those two things, you can develop what almost seems like a psychic connection, where your finger is ducking/boosting the actor's mic almost before the louder/softer sound has come out of his mouth. It's what separates an okay engineer from a great one.


Schniapereli said:


> Somewhat related questions to what he said. I have seen some Wicked clips from Youtube how they bring down the mic onto the middle of the forehead. I saw a few songs at different places.
> 1. Do the mikes come with a lot of different colors (except green)? I mean, what kind of color variety do the manufacturers offer, or do they color them themselves.



Arts and crafts time, baby  No custom colors, we use artists' pigment markers to custom color lighter elements (In Jason's article, he notes that he prefers the Prismacolor brand, except on Countryman, where he uses the Letraset Pantone line (the Prismacolors aren't colorfast on the Countryman cables); I've always stuck with the Letrasets almost exclusively, although that's primarily because my experience was shaped using them on Countryman elements; I can't say how they compare to the Prismacolors on DPAs or MKE-2s. 

Most manufacturers who cater to theatre offer three colors: tan/beige, cocoa/brown, and black. I do see somebody else noted that Countryman apparently makes 5 shades, although I've only ever used their tan, cocoa, and black.


> 2. On wicked, it looked like Elphaba's mic was black. Coudn't they special order some green ones? ...I mean, they're Broadway...



It would be stupifyingly expensive to get custom colored ones made. You certainly can color them green, but for whatever reason, at least on the night you saw it, they were using a black one. It could be that they needed a spare fast, and were short on other colors, or it may have just been an overall decision that, since the skin is fairly dark, and she's wearing a long black wig, it made more sense to just use the black one that blends in with the hair, and not worry about it.


> 3. My dad tells me that a tech told him that the best place for a mic is between the eyes (where the unibrow is on most actors) because of the sinuses vibrating. Is this true? I did not see them like that on wicked. Is it just harder to hide?...



There was a study recently done by a grad student in acoustics in the UK on all sorts of placements, both ones visually usable and those, like in the eyebrow range, that you'd never use in real life. I can't recall if this placement was included or not, but I'll try to track down a link to the study report. 

That said, that far down, you'll never use it, because you want it to be hidden. In locations where it can be easily hidden, centered on the forehead near the hairline (which, of course, is only a general placement guideline, since hairlines vary, see Jason's article for a bit more on this) is the best compromise of sound quality and invisibility.


> 4. Is this why Broadway uses straight forward face lights as oposed to McCandless' version of 45* angles. Is it to hide their microphones better?(no shadow, so they just match the color?) I could only see them when the camera angle changed to a view point higher, or more to the side than the audience sees. (I could see the shadow)



Nope, you'd have to ask the lighting designers why they prefer any particular positions, but it has nothing to do with helping us out! That said, Broadway doesn't as a rule use straight on lights, or 45 degrees, or 30 degrees, or any other position. They use lights wherever the designer chooses for the look he/she wants to create (assuming, of course, that they have the physical means to put a light there).


> 5. Do they glue the mic down, or tape it? (could not see tape)



Tape, although at the forehead it often isn't necessary to tape it at all. With an elastic loop, it's almost always held closely enough in place on its own, and when using bobby pins or wig clips, it's often clipped close enough to the front of the head to not need to be taped. But when it is, some variant of clear medical tape is used; I think I've posted extensively on types of tape and how to use them here before, so try a search for that.


> 6. I have heard other places that they store their mics in an airtight box with water absorbant packets. We currently hang the mic upside down with the connector end between 2 screws in the wall. The cords had been coiled with the packs before, and this was supposed to help straighten them out. It hasn't worked very well so far. Do they coil them up in the boxes, or do they get really long and straight boxes? (if they really do that) Is our method of storing lavs upside down on a wall a good system?



There's no hard and fast rule, each person has his own way of doing it. What's common, though, is to LOOSELY wrap the element around the pack, and then store both either in a caddy lined with foam (with cutouts in the foam to hold the transmitter) or hung up in one of those shoe organizer deals (bunch of shoe-sized pockets on a long sheet, designed to be hung over the back of your closet door).

The only mic I own that I store with a dessicant is my matched pair of Earthworks QTC-30s, because the diaphragms are sensitive to changes in moisture, and I use them as measurement mics, so the accuracy is important to me. That's why I took to carrying them with me on the plane, rather than shipping them in my workbox on the truck or in my checked luggage in the (non-climate controlled) baggage compartment of the plane.


> 7. When miked over the ear, I heard they should be about 2 cm past the ear. Is this true? We have always put ours more forward. We have MKE2's but they are black, so could they pick up well and still be well hidden?



That sounds about right, but it will vary for each actor. One of the downsides to over-the-ear mics is that they are very, very placement-sensitive. Even just a few millimeters of difference can make a huge change in the quality of the sound. Generally, you only want to mount mics over-the-ear if you absolutely can't use a forehead placement.


> 7.5 How good is the SM58 Shure microphone? I think I have seen it on TV being used for bands, and I think I saw some also being used for violins on an orchestra.



It's a pretty common vocal mic, perhaps the most common. It's okay for some things, there are better options for others. Key strongpoints are that they're very consistent, they can take a beating, and every sound shop in the world has plenty of them available, because they're so commonly used. 

While you may have seen them being used on violins in an orchestra, I'd be surprised. Condenser mics of varying sorts are much more common for string instruments.


> 8. What are other good mics for other miking situations.



That's like asking what's a good car. There are hundreds of mics out there, and most of them are very good in certain situations. If you have a specific situation, it's easier to answer that question, but even then, it's a matter of opinion; you can ask what mic to use on an acoustic guitar live to a dozen engineers, and you'll likely get at least two dozen answers, all of them equally valid.


> 9. We also have an SM58, which the singers like to keep very close to their mouths. I have seen lips actually touching the grill on TV, but it still had good sound.(and the manual says optimal performance is from 6'' to touching the lips) Our mic still has a lot of P's, B's, breathing, etc. What is used to professionally fix this? Can this be achieved with 1 graphic EQ, and a compressor?



A windscreen can help, to an extent. Compressors can, as well, but only so much. Biggest advice is to get your singer to back off the mic. Some singers do like to "eat" the mic, because that proximity effect bass boost is part of "their sound", but in general, it's poor mic technique.


> 10. Whenever I see miked drums (like on SNL, or other bands) it looks like the mics about the toms are similar to instrument mics, and they are pointing horizontally instead of down. Does this create better sound, or are they omni, or is the cardioid pattern off axis? Or is it something else? (have I just never seen it right?)



It really depends on the mic, and the situation, and the engineer using it. Some engineers prefer a mic at right angles to the head, others want it at a slight angle, the idea being that the mic is placed closer to the outside of the drum (ie, out of striking distance of the drumstick), but is aimed to pick up the attack of the stick hitting the head in addition to the "body". Odds are this is what you're seeing, but due to camera angles, you're misinterpreting it as being horizontal.

Hope this helps,
Andy


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## SHARYNF (Jan 14, 2007)

While the mic is indeed onmi directional, once you place it directly on a surface *head/ face etc, its characteristics change quite dramatically, you begin to get a boundary effect. While the pattern allows for pickup in all directions, it still is sensitive to the sound level distance. It is also worth noting that an omni mic is only onmidirectional in a single plane. It is fun to experiment how the placement and direction of the omni mic like an E6 directly on a head does offer different tonal and directional performance. This is why the over the ear placement is so problematic, since not only the position but also the relative distance to the head varies. It is one of the reasons why the mic directly on the forehead works, in addition you are not as influence by the distance to source issues (ie the mouth) 
Sharyn


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## Van (Jan 19, 2007)

kovacika said:


> As for #6, ive never seen sealed boxes, but I have seen condoms. The touring Chicago uses condoms to protect their mic transmitters (sennheiser sk5012's) from actors sweat.


 

Ok minor Hijack. We recently did Assassins. Had something like 16 folks with wireless mics on stage. We used un-lubricated condoms for the packs. My Production Manager had to make a run to pick up stuff and the Sound guy ask *her* to pick up more batteries and condoms as we were running out. So here is my PM , in line at the grocery store with a half a case of AA batteries and *giant* boxes of un lubricated condoms. < My boss is a beautiful woman in who just turned 50 and looks an lot younger> She had an old lady in line in front of her and an old lady behind her and the checker is about 60. After a lot of side long looks from the other ladies in line she gets to the checker, who doesn't say a word to her. After she pays the checker hands her the bag full of stuff and still doesn't say a thing to her. Kelly starts to walk off then turns and say to the checker, " Oh I need a receipt. This is for work." She said the look on the ladies faces was priceless.  
I love this industry !


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## Andy_Leviss (Jan 19, 2007)

My favorite was the receipt I submitted for petty cash on a massive televised awards show that my college did (still does, annually--the largest student-produced broadcast in the country). It was for a box of unlubed condoms, a package of kitchen sponges, and a tube of KY Jelly. Raised a few eyebrows at the executive producers' meeting, until it was explained that the condoms were to protect the mics*, the sponges to rig shock mounts for a few mics, and the KY because the sound rental company had brought shock mount inserts for the wrong model of lectern (NOT podium**) microphone, which was slightly smaller than the mics we were using. KY was the only way we could get the mics into the shock mounts!

--A

*-If you only put the condom on, you're often just wasting time and money. To be effective, you also need to stuff the top of the condom with a couple cotton squares (you buy them at the pharmacy, they're usually used for removing makeup and that sort of thing) to keep the sweat out.

For another entertaining story of an adventurous condom buying outing while I was on tour, see http://www.onefromtheroad.com/index.php?p=35 (there are a couple missing parenthesis in the article, sorry about that...not sure why they got lost when I transferred the article from my old site, but just noticed it now, and don't have time to edit it at the moment!)

**-A podium is a raised platform you stand on. A lectern is the thing you stand behind to give a speech. So if anybody calls those gooseneck mics you use on the lectern a podium mic, they're actually using the incorrect term. It's a pet peeve of mine


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## jonhirsh (Jan 20, 2007)

;There is a reason us ligthing guys call cloths pins C47's. Producers dont ask questions about what they dont understand.... you should call condoms, mic protectors or mabey C69's just a thought


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## SHARYNF (Jan 21, 2007)

Just to give Andy a hard time ;-)

I you look in bigger dictionary you will see;
Main Entry: po·di·um
Pronunciation: 'pO-dE-&m
Function: noun
Inflected Form(s): plural podiums or po·dia /-dE-&/
Etymology: Latin -- more at PEW
1 : a low wall serving as a foundation or terrace wall: as a : one around the arena of an ancient amphitheater serving as a base for the tiers of seats b : the masonry under the stylobate of a temple
2 a : a dais especially for an orchestral conductor b : LECTERN


SOOOOO it is infact acceptable to use it as also meaning Lectern

Sharyn


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## Andy_Leviss (Jan 23, 2007)

LOL, in the same spirit, it's not acceptable, per se, it's just commonly used enough that the editors of Merriam-Webster decided it should be included. A dictionary doesn't reference proper usage alone, but also common usage. Especially with a secondary definition, the fact that the definition appears doesn't mean it's a correct use of the term, it just means that enough people misuse it that way that the dictionary would be incomplete if it didn't include reference to that usage.

If you look up "ain't" in the dictionary, you'll find it. You'll also find "irregardless". Even so, neither is considered a "real" word by those who care, and if you use them in a term paper, your teacher will without a doubt mark you down for it (I know you're not a student Sharyn, just making an analogy 

Likewise, M-W's second definition for the phrase "begs the question" (actually, it's listed there as "beg the question", but it's commonly used as "begs...") is technically considered an incorrect usage of the phrase. It's included there because the phrase is so commonly misused that it's essentially become a de facto definition, regardless of the original meaning of the phrase. See http://www.mtannoyances.com/?p=445 for a good summary. (Yup, that's my other grammar pet peeve, misusing that phrase; it drives me nuts that one of my favorite songs by one of my favorite bands--Eddie From Ohio's "Number Six Driver"--misuses the phrase in its chorus. Argh.)

--Andy


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## SHARYNF (Jan 24, 2007)

Actually to have more fun with this, in fact the english language is base on this incorporation of common usage into the language.

The most memorable example for me is that Bald was properly used to describe someone with white hair, hence the name bald eagle. Over time it was used to describe someone with no hair. 

Typically once it makes it into MW or Oxford, it is considered proper

If you look today you will see it is listed as the 2nd definition

If you look at the 1913 dictionary you will see that NONE of the definitions we are talking about are even included, it is used for the wall and foot definition

http://machaut.uchicago.edu/cgi-bin/WEBSTER.sh?word=Podium

SO by your logic all of the common usages today are incorrect 

If you look at the Oxford on line it shows that in North America it is used as meaning lectern

http://www.askoxford.com/results/?v...570&textsearchtype=exact&sortorder=score,name 

Lol
Sharyn


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## Van (Jan 24, 2007)

See I just call it " that speechifying thingy" and "That Platformy Thingy"


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## Andy_Leviss (Jan 24, 2007)

LOL, Sharyn, one of these days we'll finally cross paths and have to share a round of drinks of some sort


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## SHARYNF (Jan 25, 2007)

Your on, but my Husband and I were born and raised in NYC.
Now that we are in Alaska, a bit more of a trip

Sharyn


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## DarthFader (Feb 21, 2007)

Just joined up today and this thread caught my eye. Have to agree with the idea that no amount of electronics can replace quick fingers on the faders. What I haven't seen mentioned is that when two actors are very close, you might very well need only one mike to get the job done. If for example you have a song with two actors singing directly to each other you can turn one mike off completely, and just make small adjustments to the fader as they switch. You can listen to both mikes and see which sounds better. Sometimes you will find that the better solution is to juggle the faders on both, but make it as easy on yourself as you can.

An iteresting thing to try is to punch down the phase button when the comb filtering sounds the worst and hear the problem go away. The heartbreak comes seconds later when the actors move a half inch and the problem is back worse than ever 

Another couple thoughts that might help. Since we are fairly small and a pretty tight knit group on the shows we produce I can maintain a relationship with the music director and get my two cents in as early as audtions. A single weak voiced actor on stage can really upset your mix. Since he/she is weak, their mike gain must be higher, and other actors bleed into your mix at a higher level. It's entirely possible to see more strong actor audio in the weak actor channel than in his own channel. This really upsets the applecart when you are expecting a few db of gain reduction to resolve the interference and strong guy is still overpowering weak guys mike. The same people may still be cast but we establish early that problems may result that we may not be able to resolve to everyone's satisfaction. It makes it easier down the road if you get into a situation were a small change in blocking could make a big difference in the sound of the number. Of course not every production situation allows that kind of cooperation. 

The other thought is that adding a few ms of delay can _change_ the comb filtering problem. Its sort of like increasing the distance between the actors so the actual physical distance where you get objectionable filtering issues will change ...maybe to somewhere allows the scene to play better. In a pinch, try it and dial the delay around between 2 and 10 ms and see if it helps. 


3. My dad tells me that a tech told him that the best place for a mic is between the eyes (where the unibrow is on most actors) because of the sinuses vibrating. Is this true? I did not see them like that on wicked. Is it just harder to hide?...

Not sure about that because I don't think I could sell that visual to our directors. Your mileage may vary. There are some shows where being able to see the mike is OK, but most often considerable effort goes into finding a place that sounds OK and looks good from row five back.


5. Do they glue the mic down, or tape it? (could not see tape)

The name of one of the tapes we use is "Transderm" but most clear first aid tapes are similar. We use an alcohol wipe to clean off any makeup, oil, sweat etc, and if the actor sweats a lot we wipe again with a cotton ball wetted with anti-perspirant. Let that dry throughly before you continue. After the mike is in place, your makeup crew can carefully cover the tape to help hide it. (It has a texture that helps it blend in and makes it accept the makeup better.) I like them just out of the hairline so that just the capsul is visable and you have enough room to keep the tape out of the hairline. The halo rigs as described here work well in some cases. 


6. I have heard other places that they store their mics in an airtight box with water absorbant packets. We currently hang the mic upside down with the connector end between 2 screws in the wall. The cords had been coiled with the packs before, and this was supposed to help straighten them out. It hasn't worked very well so far. Do they coil them up in the boxes, or do they get really long and straight boxes? (if they really do that) Is our method of storing lavs upside down on a wall a good system?

I can't comment on the MKE's since all our lavs are Countyman B3s with a few E6s. The B3s are extremely rugged, but the cords take a real beating from the use they get and contact with all kinds of hair gunk and makeup. We have yet to loose one to anything other than cable failure. A five dollar lighted magnifying viewer is a good investment. If you look very closely at a mike that sounds bad, you will usually find either hair spray or makeup in the cap grill. It's never easy, but always possible to clean it out. Its a good idea to keep a few spare caps on hand in case one departs during a show. As someone else mentioned even one drop of sweat is a mike killer. You aren't likely to get the mike back in the show that performance. Spares are important. Ater drying out some B3s for the third or fourth time we found they sounded really bad. (Accumulation of dried out salts from perspiration?) We really had no options since they were no longer usable. Extreme measures seemed reasonable so I just dunked them in distilled water and swished them around. After that I used a fresh cup of distilled water and more agitation. I hung them out to dry under a 40W orchestra stand light and by the next day they were pefect again. 
We use a board with pegs on it to store the mikes during the show. Each peg is spaced far enough to allow the coils to be about 2.5 in diameter. An inch or so of pipe cleaner is wrapped around the coil to keep them from "mating" while they are stored. Each peg has a number, and each mike has a number on the connector so we can see at a glance who has or has not returned their mike. Belt packs (Shure U1) live in a plain old clear front shoe bag. Again slots are numbered and the packs are numbers on the packs show through the clear bag. Every actor gets the same mike and pack every show and we have everyones phone number on record. (When we did Wizard of OZ we had four B3s that got "lost" prompting me to start this system) Although I encourage actors to have our backstage audio guy take the mike off for them, some actors that have been with us for many shows take their own off carefully. Kids tend to rip it off by the cord  Its hard to get through to a kid that the "wire thingie" and the "box" cost 10x the price of my first car. Regardless every actor is responsible for verrifying that their mike and belt pack are back in the numbered location. We have established that we will call the actor back to the theater regardless of the time if thier hardware is discovered missing. 

7. When miked over the ear, I heard they should be about 2 cm past the ear. Is this true? We have always put ours more forward. We have MKE2's but they are black, so could they pick up well and still be well hidden?

When over the ear is the only option, I like the E6 which of course is very close to the mouth. Another thing you can try is making an over the ear holder out of light solid copper wire with the cord and wire wrapped in flesh colored tape. You can use some silicone tubing over the ear part to make it more comfortable. The advantage is that you can adjust the mike position up and down the wire till you find the best spot and then trim it to length and cover it with tape. Trial and error gets it done when measurements won't. For less cooperative actors we keep a staple gun handy to secure wire and capsules directly to the skull


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## howlingwolf487 (Mar 4, 2007)

Andy_Leviss said:


> **-A podium is a raised platform you stand on. A lectern is the thing you stand behind to give a speech. So if anybody calls those gooseneck mics you use on the lectern a podium mic, they're actually using the incorrect term. It's a pet peeve of mine



AMEN BROTHER! Oh, let's not forget: they're LAMPS not LIGHTBULBS...


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