I am a lecturer at a private university and was wondering if any of my SSD peers have any advice on how to clean up the diaphragms on the various condenser mics that we have. We have the ME 66 mics, the AT 4073 gradient condenser mic's and the AT 8035 gradient condenser mic's. They are constantly being used by students and I am sure that they have never been cleaned. I was out with a friend and he had the ME 66 and when I listened to it, it sounded a lot fuller and cleaner than our mics which made me suspect that they had never been cleaned. There is no buzzing but I am sure that they need a bit of a make over.



6 Answers 6


Hi Chris

I have had extensive experience with students and mics - that sad reality is that they do not have respect for the equipment and do not handle it with care. Every time a mic gets dropped or banged against something there is a chance that the diaphragm will sustain some damage. This is a fact of life. A mic with a damaged diaphragm may continue to work, but the sound characteristics will most definitely be affected. Therefore, even if you clean them, the odds are they will not sound much better.

Is sound quality a crucial factor or is the technique you are teaching more important? If it is the former, you are probably looking at the expense of new diaphragms. Also, unless there is rigorous control over future usage, it will not be long until you are back in the same situation. If it is the latter, I wouldn't bother fiddling with them until they stop functioning altogether.

Obviously you know your requirements and intentions better than anyone else but, personally, I would send the 4073 to the agents to be refurbished and then lock it away so the students can't get hold of it. Let them screw the others up and, when they do, replace them with something cheap and robust. Our students required mics for field recording and interview purposes, so I bought a pair of EV635As and (nearly 10 years later) they are still going strong.

  • 1
    @Bluesman69 - Funny story my friend/ university professor told me years ago. In college, our class had a portable recorder and a few EV635As for going and grabbing interviews for our projects. One year, one of the mics sounded awful so he sent it in to EV to get checked up and cleaned. When he got it back it from EV, it sounded good as new with a note attached "Next time, keep it out of the pool" He had no idea what they were talking about until he realized one of his students had done an interview piece with the university swim team and conducted some interviews at the pool.
    – user6508
    May 10, 2011 at 15:12
  • @GaryMegregian - Similar thing happened to me, except it was a Sennheiser (can't remember the model) and unfortunately could not be resurrected! This is actually what motivated me to get the EV635As.
    – Bluesman69
    May 11, 2011 at 9:30

I really wouldn't attempt to clean a mic myself. I think it's a good time to get it serviced and checked up. (unless that's also what you mean).

I brought my mic to Sennheiser South Africa and they serviced it for free... Not sure if they would have charged me if it were damaged. They even cleaned some corosion off my cable.

  • Exactly what I was going to recommend!
    – Utopia
    May 9, 2011 at 16:57

To me it sounds like they need to be serviced.

I have no experience with the AT's but the ME66 don't seem easy to take appart. I guess you could do some gentle cleaning with a soft brush, but I kind of doubt it will solve your problem.


Right, so, mics are delicate but they're not made of wafer-thin glass :) Here's some things you can do to clean up your mic:

-Any grilles or screens can be taken off and given a nice wash in warm water, then rubbed with isopropyl alcohol to make sure it's completely dry and princess pretty.

-If you have a capsule-type mic, take the capsule off and wipe down the contacts with a slightly damp alcohol-soaked cotton swab.

-You can clean the diaphragm, just be careful. I've used damp swabs, but I've been told for more delicate mics, use a little cheap paint brush, stick it into a stream of steam coming off of boiling water or a teakettle for a few seconds to get it damp, and then gently brush off all dust and schmutz. Read this linkydo for good info. He brings up the point that some old mics use PVC in the diaphragms, so know what you're working with before you dive in. If your diaphragm is in serious trouble, it should be replaced professionally. You'll know if this is the case - it should sound terrible.

-Down on the connector side, your XLR can get pretty nasty. These are pretty easy just to replace. There's a little screw holding it in - take it out. These are just the connector portion of any XLR cable connector. A little solder and you are set. If you're not comfortable with soldering, there are crimp and screw down terminal connectors as well, although soldering will be the best way to preserve the cable length that may be a bit precious.

-I regularly use CAIG Labs DeoxIT to keep the XLRs in good shape. Just squirt in a little bit, then use an XLR cable end to work it onto the pins and wipe up any excess. I would ask the rental/borrow department at the school to make this part of their check-in process.

And, of course, if it ain't broke - don't clean it!


Hi Chris,

I'm not sure its something that just anyone can do. You would need to find a specialist to refurbish them. Contact Sennheiser and AT directly to find someone local to you.


Did you compare the 2 mics on the same PA system? If not, it is likely that you are hearing a difference in PA's amps, Speakers, rooms, and even mic placement ( how close to the mouth the mic is held makes a HUGE difference in the sound) and not Mics.

I am reading your comments 'cleaner' and 'fuller' as high frequency response and lower frequency response (I could easily be wrong here). Older and badly treated mics will lose their high frequencies. The lows - specifically low-mids associated with male voices - are not going to fade as much.

  • Umm, not sure where you are coming from regarding testing on a PA!!
    – Si Charles
    May 13, 2011 at 10:52
  • I assumed when he opened with "I am a lecturer", that he was using the mics as part of his teaching/public speaking. My bad. May 13, 2011 at 17:36

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