jerryfreak, the only capsule for which Schoeps recommends regular maintenance is the three-pattern MK 6, including the CMTS stereo microphones which used a version of that capsule type. But that isn't because of the membrane; it's because of the pattern-change mechanism and the synthetic rubber seals that are part of it. Otherwise Schoeps doesn't recommend "regular" cleanings of capsules unless you mean on a time scale such as every 10 - 15 years in normal operation. Which is like saying, "I take a bath every three months or so whether I need it or not."
And they don't recommend that anyone but themselves do the work, particularly where their multi-pattern capsules are concerned. A person who wasn't specifically trained in how they are made, and who lacks certain specialized test equipment, would never be able to put them back together in proper alignment after opening them. I've seen a couple of Schoeps mikes that were basically destroyed by a repair person who is very well known--even revered in some circles--for his work on other types of studio condenser microphones. There's far more risk from inexpert (or self-appointed "expert") disassembly, cleaning and reassembly than from the lack of cleaning under ordinary circumstances.
Back to the main subject--when I see people assuming that smoke would be likely to dull the sound of a microphone, or enthusiastically accepting the (basically false) idea that using ultra-thin membranes would make a major improvement in the high-frequency response and impulse response of condenser microphones, or the (also not very true) idea that various possible membrane materials each have a sound quality of their own, I think there must be a widespread misunderstanding about how condenser microphones work. A membrane's freedom of movement isn't determined mainly by its own mass or inertia; it's determined mainly by air friction within the capsule, of all things.
The backplate is perforated rather than solid, and there's a small chamber in front of it (between the membrane and the backplate) as well as another one behind it. On each vibration, the air within the capsule is pushed or pulled (very slightly) through the holes or slots or slits in the backplate, and in the process there is friction, which impedes the air flow between the two chambers and thus controls the movement of the membrane. That's part of the damping system which keeps the capsule from having a huge honking resonance around one frequency. Anyway, that friction is the dominant parameter in a capsule. Adding (or subtracting) moderate amounts of mass to (or from) the membrane won't change its frequency response or impulse response characteristics much.
The main risk from smoke and dust (and the goo that cigarette smokers breathe onto a diaphragm when they sing right into the mike) is more a matter of operational reliability, especially when combined with moisture in the air. When moisture mixes in with the goo, it can create a lower-impedance path for the polarization voltage, which will basically short-circuit the capsule, causing the microphone to go dead either temporarily or permanently. Of course moisture can also come from breath--so close-miking a vocalist without using a popscreen of some kind is a big one-two punch to the capsule.
My favorite aunt used to be an active New Yorker, but nowadays she can hardly walk from one side of a room to the other without stopping to catch her breath, because she has chronic emphysema from decades as a smoker. It's bad enough what that stuff does to a replaceable piece of gold-evaporated tensilized polyester film; it's terrible what it does to the cells of living beings. If people are aware enough to be concerned with what happens to their microphones, I would hope they'd also carry that awareness over to include themselves and each other.
--best regards
Topic: Schoeps MK4 Question (Read 7599 times)