[Klaus Heyne]

It's a terrible problem, but one, I'm afraid, that is not easily solved by the mic's owner. The foam, once liquified or getting gooey in the process of deterioration is very hard to remove from a diaphragm/membrane, because the same solvents that would remove it will also dissolve the diaphragm.

ElectroVoice mics like the RE 20 are notorious candidates for having this problem, and their inner foam construction around the capsule needs to be replaced every time such a mic goes in for service.

[zione]

Hello,
A well known tech gave this advice to a collegue who owns a studio located very close to the Mediterranean:
Storing the mics in jars with silica gel inside.

I also store my mics this way; I've found a silica gel that change color from yellow to blue when it absorbs humidity, it takes 2-3 months into the jar to became blue.

Do you see any issue, for example excessive dryness, using this method?

Cheers
Ugo Venturino

PS: sorry for the poor quality pics

[Klaus Heyne]

Ugo,
Your method of keeping a microphone dry seems sound, and I see no chance for 'excessive dryness'.

I am just curious about the particular color changes you mention: the silica gel I use is BLUE when dry, and YELLOW-TAN when saturated. You may want to double check this!

[zione]

Klaus, here is an excerpt of the product brochure.

BTW when the silica grains are saturated if you put them for 3 hour in the owen at 90

[aracu]

There is some good advice on this thread, and it saved me a lot of trouble.

I have gotten in a habit of using a pair of Sennheiser 800 on film shoots and keeping them in a humid room.  I noticed that one of them had dropped about 10 db in output, and the other had become hypersensitive to movement, or being touched, which would cause the sound to distort and go down in volume for a moment.

Sennheiser repair said these problems could not be caused by humidity, but just to make sure I kept the mics for a couple days in an airtight bag with a large quantity of silica gel crystals wrapped in fabric (the crystals can be bought cheap, marketed as kitty litter in pet shops). The mics sounded to me as good as new afterwards.