Microphones Too Close To Sound Good?

DeLafyette

Member
Hell Everyone,

I am a junior in High School and we are doing a production of "Curtains" I have alot of wireless mics for the show (16 total) and 4 hangs and 4 floors. I am running off the GB8 soundcraft mixer and i am currently having a problem. Whenever two actors get really close together. The sound becomes very hollow and very...just weird. Im not exactly sure how to explain it but its there. It doesn't sound right. I have been making up for this by turning one actors mic down and keep the one talking up or vice versa. It all depends on who's talking and when. Is there a way to fix this without doing that?

Thank you so much,
Sean
 

cmckeeman

Active Member
try switching the phase of one of the actors mics. getting picked up by both mics might be causing the weird interference in the mixer.
 

DaveySimps

CBMod
CB Mods
Premium Member
This is actually quite common. It is known as comb filtering. The sound is being picked up by both mics, which (in simple terms) adds a delay to the initial source when reproduced through the speakers. It can be minimized through the exact technique you have been using. You can also reverse the polarity of ONE of the microphones. On your mixer, this is the button on the channel strip under the phantom power (48V) button that is a circle with a line through it. Often times this is helpful. It is a constant battle in musical theatre reinforcement.

It would also be helpful to mute you floor and hanging mics when they are really not needed (save them for the chorus as). They will also cause the same issue as well.

~Dave
 
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museav

CBMod
CB Mods
Departed Member
As noted, the issue is the sound being picked up by multiple microphones but at slightly different times such that when the microphones are mixed together the delayed signals combine with the original signal in a manner that affects the resulting frequency response.

You can invert the polarity of one of the microphones involved but all that will actually do is change how the frequencies are affected and may sound better or worse. You could also implement a two channel system where you essentially have two identical speaker systems with microphones routed to one or the other, say the female lead to speaker system A and the male lead to speaker system B, thus the two microphone signals do not have to be mixed together. Where that is not feasible (i.e. in the vast majority of situations) what you are doing with riding the channel gains is typically the most appropriate action.

And seconding Dave's suggestion to always mute or turn down any microphones that are not being used. Each open microphone reduces potential gain before feedback and can introduce relative phase, and via that frequency response, anomalies.
 

PolishGuy

Member
what you are doing with riding the channel gains is typically the most appropriate action.

^^^
This is the simplest solution if you don't have time to fiddle around. If the two individuals are face to face, easiest thing to do is lower the mic on the shorter actor as she/he would be looking up at the taller person, and the taller person's mouth won't be talking directly into the shorter person's microphone.
 

themuzicman

Well-Known Member
When you mix a show or musical where everyone is mic'd you do what is called "Line Mixing". Only the fader for the actor talking is up, everyone else is down. Be sure to hit all of your pickups else you'll be cutting off the first or last syllable of every line!
 

DeLafyette

Member
Thank you so much everyone!!! I have been using the faders to get rid of that sound and i also have the phase on for one of the actors who are close together. I also have been line mixing the whole time. Thanks for all the help!!!
 

chausman

Chase
Fight Leukemia
When you mix a show or musical where everyone is mic'd you do what is called "Line Mixing". Only the fader for the actor talking is up, everyone else is down. Be sure to hit all of your pickups else you'll be cutting off the first or last syllable of every line!

Really? Every line? I've never done that.
 

bishopthomas

Well-Known Member
Yeah, me neither. Of course, if an actor is not on stage the mic is off (fader down, I never turn off channels), but I like to keep faders up for all mics on stage. Helps me keep track of which mics are in use, besides the other obvious reasons.
 

TimmyP1955

Well-Known Member
I would think the thing to do would be to turn down the mic not of the shorter person, but of the stronger-voiced person (they will both be looking at each others' mics, so height should not be a factor). A 10dB reduction may be all it takes.
 

NZM

Member
The quickest and easiest thing to do, as already noted, is to ride the faders and pull back one of the mics that are in close proximity to the source. Another thing that can help is to add a very small amount of delay to one of the channels. This is easy with most digital desks, but not so easy with an analog mixer. Keep the delay short so its is not noticeable, say 5-15ms. The delay on one channel helps to ensure that by the time the signals are mixed there is little phase alignment to result in the comb filter effect. This works ok for voices, but would not work as well for something generating a more prolonged pure tone (say a flute or violin) or a very percussive sound (say drums or bass). The issue is all about the 3-to-1 rule for microphone placement. Adding a small delay has a similar effect to increasing the microphone separation/spacing.
 

NZM

Member
I don't see how VCA's would help you mix if you're only using one fader at a time. I'm calling bull****. :)
VCAs can help when you have groups of actors/performers who always appear together. But if you have the issue of two actors getting "up-close-and-personal" such that once audio source is being picked up by two microphones, the VCA won't help.

POP groups on the Midas digital desks also come in handy - depending on the show of course and finding logical groupings, or for presenting the channels that are part of a specific scene. But VCAs and POP groups only help with the overall control of which actor's mics need to be on at any time, they don't help eliminate the issues caused by abusing the 3:1 microphone placement rule. Riding the individual faders does that. But I find I am doing that pretty much constantly during a show anyway, so when I see two actors about to breach the 3:1 rule I am ready for it. Of course the "readiness" depends on how well rehearsed I am for the show - first time it happens can easily catch me out! Then I need to note it in my mind/memory or on the script.
 

bishopthomas

Well-Known Member
VCAs can help when you have groups of actors/performers who always appear together. But if you have the issue of two actors getting "up-close-and-personal" such that once audio source is being picked up by two microphones, the VCA won't help.

Yep, exactly. The person I was responding to was suggesting "line mixing" (never heard of that until this thread) where only one fader is ever up at a time. Then DCA's are pointless (in most circumstances).

But I find I am doing that pretty much constantly during a show anyway, so when I see two actors about to breach the 3:1 rule I am ready for it. Of course the "readiness" depends on how well rehearsed I am for the show - first time it happens can easily catch me out! Then I need to note it in my mind/memory or on the script.

Again, I'm right there with you. Even after just a couple of rehearsals I usually have a pretty good feel for when polarity issues will occur, what lines/words get screamed, etc. If I'm doing musicals it's usually elementary through high school where you don't always get professionals with control. It's still our job, though, to polish the droppings. So I guess if "line mixing" is what works for you it's not "wrong."
 

NZM

Member
Again, I'm right there with you. Even after just a couple of rehearsals I usually have a pretty good feel for when polarity issues will occur, what lines/words get screamed, etc. If I'm doing musicals it's usually elementary through high school where you don't always get professionals with control. It's still our job, though, to polish the droppings. So I guess if "line mixing" is what works for you it's not "wrong."
I have not heard the term "line mixing" before either. The only time I would have only one fader up is if there is only one actor speaking/singing for an extended period of time. My personal mixing process for musicals/theatre, is that if an actor is on-stage and will be speaking/singing, then their mic fader is going to be up/on, unless I know they will not be speaking/singing for an extended period such as during someone else's solo/soliloquy etc. but "riding" the faders (adjusting the levels as needed) as actors speak/sing is a necessary component of operating for musicals/theatre, especially with amateur performers, so pulling one down (not necessarily completely off) when two mics are in close proximity of a single source is a pretty simple task. My fingers are normally on the faders of those talking/singing anyway. I do not operate with the channel mutes, except in the situation where an actors is finished with producing sound such as when they "die" on stage but remain as a corpse for a while - had this several times with Les Miserable recently and each time someone died we "paid tribute" with a ceremonial "muting" of their channel, and of course the unmute when Fontine returns at the end.
 

NZM

Member
That's EXACTLY my technique. Maybe one day we'll double team a really complicated show on a huge console.
Sounds like a plan. I have Sound of Music coming up in May/June and will be operating on the Midas XL8 - is that big enough? Expecting 30+ wireless headsets plus an orchestra, so the use of POP groups and automation will be essential. It will be a 2-man op with vocals on Area A and orchestra on Area B. But you will need to travel down here to play along :cool:
 
In regards to my previous post about VCA's, I should have been more clear. If a console has VCA assign automation, each scene or song of a show can have differences in what channel is assigned to what VCA. For example, the opening group number could have VCA 1 be men, VCA 2 be women, and the rest for various sections of the orchestra. The next song, a duet, could have the leading actor on VCA 1 and the actress he's singing with on VCA 2. This allows the person mixing to work in the master section of the console for the majority of the show, rather than reaching from one end of the board to the other in order to mix a song.
 

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