What are the operating temperature limits of microphones?

Question

A question about the operating temperature of various microphones.

I went through the manuals and spec sheets for several microphones that I own, and a few others. Almost nowhere I find a specification of the minimum and maximum operating temperatures.

Of course I was wondering about this because of some situations which might be more or less common in sound design but are probably not standard microphone usage.

For example: - freezing a microphone to record breaking ice when it melts again - submerging a microphone (obviously a hydrophone) into boiling water - recording the sound of very hot pipes by sticking a contact microphone on them - having a microphone close to a source of fire or extreme heat

There is a lot written already about using rugged and/or cheap microphones in situations in which you risk damaging your mic. Which is good advice.

But when do you risk damage just because of the temperature? What are the things to be aware of when using a microphone is very low or high temperatures? I guess there is some kind of common threshold for the different types of microphone (dynamic, condenser, electret, etc.)?

Answer 1

I called DPA a few months ago to inquire about very high temperatures and their 4060 range. Aside from the temperature range in their specifications, (pdf), they weren't sure themselves and redirected me to their European distributor. They didn't have exact numbers either, but an hour later they called me: they tested it by putting a mic in harms way - great service! They found the following:

• the microphones were operating as expected up to the specified 45° C.
• they were stable and fine at about 70° C too (!) (forgot the exact number, could have been 80 too), above that they are destroyed.
• while being heated from 45 to 70, their behaviour was unpredictable and there was noise in the signal.

They also told me that Boeing uses their mics in jet engine testing, where they last only a few minutes before they are fried, but just enough to get usable measurements.

Answer 2

Hot temperatures:

This is very easy: Put a finger beside your mikrofone. If it get's too hot for your finger, it get's too hot for the microfone. Same for boiling water: there are other methodes to records bubbles. Play around with compressed air and you get similar results without a boiled hyrdophone.

If you want to record fires or explosions, put the microfone beside the fire, not over it. This gives you a good result without fire, hot air and so on.

Cold:

I made lot of records here in the swiss mountains. In winter it's about minus 20 degrees or more, no problem. If you record outside, at minus temperature, you have to acclimatize your gears. Windshields and the microfone itself starts crackling and making some noise if they get in the cold. this could take an houre or two. Use a good winshield-zeppelin, because the temperature falls much softer than putting a microfone out in the cold air.

If it's cold and dry, you should not have much problems with your gear. BUT: This is very important: If you bring in your equipment (recorders or microfones) from minus temperature-outside into a 20 degrees warm room, you have to be very carefull! The temperature on the mikrofone is minus degrees and freezes the warm, condensing water from the air immediately! If water freezes, you know it expends and could break electronic components out of the circuit boards without problems. Freezing water is very powerfull! Imagine the waterbottle in the freezer - it breaks. So, if you go from cold into a warm room with your equipement, it needs to acclimatize too. Also in zeppelins, the temprature rises soft, picks up the condensing water and helps to protect the microfones.

Best

Guido

Answer 3

Maybe protect the mic warping cling film around it not really sure what else to say its a tough one.

when it comes to putting near pipes depends on the mic and how it was made. just remember that they put wax in mics and if that melts onto the electronics then it probably will kill it but who knows, give it a try

defiantly use dynamic mics as they are build to last. try a shure pg58 as they are cheap

hope this helps

Answer 4

As the other said here, microphones are delicate equipment. If you can't handle it, neither can the microphone.