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Thijs Stam

CMIT-5U in humidity

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I recently got myself a second hand CMIT-5U. After a long day shooting it started to crackle and distort a bit. Probably because it got colder that night. 

Is there any way to overcome this problem? Love to hear your solutions. 

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I keep mine in a small Pelican case with a couple small silicon packets whenever I'm not using it. Had a similar issue as you're describing and had to send it back to Germany, so being extra safe now. From what I was told, microscopic dust can get into the capsule due to the way the mic is designed, and when those specks take on too much moisture from heavy humidity days it'll affect the performance of the mic.

 

I'd try putting it in a case with a dehumidifier, but my guess is that you're going to have to ship it back to the factory.

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11 hours ago, Thijs Stam said:

I recently got myself a second hand CMIT-5U. After a long day shooting it started to crackle and distort a bit. Probably because it got colder that night. 

 

 

Getting colder is not a humidity thing, humidity drops as it gets colder. 

Have you got another mic for a double check? Try it when the CMIT starts crackling again. 

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2 minutes ago, Constantin said:

 

Getting colder is not a humidity thing, humidity drops as it gets colder. 

Have you got another mic for a double check? Try it when the CMIT starts crackling again. 

 

Not true.  Look up how dew point works. Ever work into the night and moisture starts collecting on your cases and gear - that's moisture in the air coming out.  It can affect mics that are prone to moisture, like Schoeps.

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3 minutes ago, Mirror said:

 

Not true.  Look up how dew point works. Ever work into the night and moisture starts collecting on your cases and gear - that's moisture in the air coming out.

 

Yes, you’re right, actually. I was thinking of how colder air (in rooms) sort of carries humidity outside, but it’s different when you actually are outside. 

 

4 minutes ago, Mirror said:

mics that are prone to moisture, like Schoeps.

 

That however is a myth. 

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@Constantin you are probably thinking of the affects of an air conditioner, which often also work as dehumidifiers. 

 

Side note, I was on a gig where we were shooting in a house, but the owners didn’t want anyone with equipment inside that weren’t shooting. As night fell, a heavy dew grew on everything outside, including my sound kit. As luck would have it, they only wanted me for the very of the day, at which point everything was completely wet. I expressed my concerns to production about powering it up after being so wet, and of course that made ME the bad guy. The lesson here is to do what you can to protect your gear because someone unreasonable will eventually make you put yourself or gear at risk and then blame you for the outcome. 

 

In the case of the OP, I keep my cmit in a case with dehumidifying packets as well. That seems to do the trick. 

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All DC-biased microphones are sensitive to humidity. Only the RF-biased ones (like many Sennheisers and some Rode, or Deity ones) are less senitive to humidity. 

 

Greetings

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8 hours ago, pillepalle said:

All DC-biased microphones are sensitive to humidity. Only the RF-biased ones (like many Sennheisers and some Rode, or Deity ones) are less senitive to humidity. 

 

 

I understand that the Deity S Mic 2 is not RF biased but a conventional DC biased design.

 

https://tyfordaudiovideo.blogspot.com/2018/09/deity-s-mic-2-shotgun-microphone-third.html

 

Rode has two RF biased models, however: NTG-3 and NTG-8. 

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14 hours ago, JonG said:

@Constantin you are probably thinking of the affects of an air conditioner, which often also work as dehumidifiers. 

 

No, I was thinking how during winter when you have the heating on the humidity rises indoors and when you open a window the cold and dry air will carry the humidity outside. 

Anyway, that’s really beside the point. 

 

13 hours ago, pillepalle said:

All DC-biased microphones are sensitive to humidity. 

 

Of course. The point was, and maybe I didn’t make it clear enough, that Schoeps mics are not more prone to failure due to humidity than other mics, with the exception of the RF-biased mics. I know people who went to the Amazon in rain season, to the Himalaya, Mongolia, the African desert, Antartica, weeks on a ship, wherever else, all with a CMIT, and all without

a single failure. 

OTOH I know of at least one instance where a 416 failed due to moisture. 

 

14 hours ago, JonG said:

In the case of the OP, I keep my cmit in a case with dehumidifying packets as well. That seems to do the trick. 

 

I think that should be SOP regardless of the mic used. 

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I was told the reason Schoeps crackle when humid is the lacquer that is the insulation on the wires in the capsule develop hairline cracks and enough moisture can cause a short.

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With humidity the dielectric constant of the air drops, and this is the reason of the noises. This is common for all external polarized condensers, but the easily of this problem occurs depends of the polarization voltage (more voltage worse for humidity) and the separation between membrane and plaque (closer worse for humidity). Only the RF polarized microphones and the electret ones are relative inmune

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A Super CMIT's DSP is self heating and hence resistant to any condensation.
It's literally like having a little heater built in, which can be an additional unexpected benefit, especially inside a wind basket.
Not so handy in hot desert conditions though, I had to remove the back cap of the basket as it was getting to hot to touch which didn't seem a good idea......

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1 hour ago, pindrop said:

A Super CMIT's DSP is self heating and hence resistant to any condensation.
It's literally like having a little heater built in, which can be an additional unexpected benefit, especially inside a wind basket.
Not so handy in hot desert conditions though, I had to remove the back cap of the basket as it was getting to hot to touch which didn't seem a good idea......

 

My Soundfields also have a heaters inside for the same reason (And is very power hungry)

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11 hours ago, traut said:

I was told the reason Schoeps crackle when humid is the lacquer that is the insulation on the wires in the capsule develop hairline cracks and enough moisture can cause a short.

there are only two outputs from the capsule, and there are no wires, unless i am misunderstanding what you are saying... 

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Two CMITs failed me last night.  100% humidity and for sure it was after night fall and the dew point as sky high. All packed up in silica gel ziplock now.  

 

j

 

 

 

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