Tips from Neumann Brand Manager on Preserving Microphones

A wide range of studio condenser microphones has recently been developed to meet the needs of home and project recording engineers. If you’re about to purchase your first condenser mic, you should be aware that while they sound great, they also require quite a bit more care than dynamic mics. This article will explain how to maintain the best-quality recordings from your condenser mic for years to come.

Many engineers are unaware that microphone diaphragms are “working” even when the mic is not plugged in, which means there is mechanical movement at the diaphragms 24 hours a day, 365 days a year. To avoid possible damaging noises and conditions, and to keep your condenser mic in tip-top shape, take the following precautionary measures.

Use a Dust Cover
Microphones not in operation should never be left on the stand unprotected. By design, condenser mic capsules and the amplifier circuit are of an extremely high impedance. Dust, ash, smoke, and other pollutants can degrade the insulating properties of the materials used for this part of the microphone. A non-fluffy dust cover will help protect the mic from dust settling on the capsule.

Use a Pop Screen
The pop screen does more than eliminate the plosive noises in vocal recordings. In close-miked vocal applications, such screens also can efficiently protect the diaphragm from almost anything, including breath humidity and food particles.

Discard Aging Windscreens
Foam material used in mic windscreens ages and degrades over time. With very old windscreens, the material decays, becomes brittle, and sheds. The particles can then settle on the diaphragm. To test for this, hold the windscreen over a flat surface and wring it in your hands. If particles show up on the surface, you should discard the windscreen.

Functional Testing
Modern condenser mics cannot be harmed by high sound pressure levels (SPLs) found in the studio. Still, there is no need to blow directly onto the diaphragm to see if a mic is working and present on the console. Normal speech is the best test, as only scratching the mics by rubbing a fingernail against the grille may not show a dropped cable leg or even gross distortion. Also, pop testing can produce SPLs at the capsule that exceed 140 dB, which may damage your studio speakers.

With older microphone types, be aware that some diaphragms can indeed be damaged by excessively high SPLs. The Neumann M50, KM53, KM54, KM56, SM2, SM23, KM88 and TLM50 all have nickel diaphragms that can be damaged by high SPLs. Also, older U47s and M49s may still have PVC diaphragms, which become brittle with age. Even transporting microphones from one part of the studio to another and the subsequent rush of air over the capsules can cause huge SPLs at the diaphragms. When moving the mics from place to place, enclose them in a case, a box or even a plastic bag.

Long-Term Storage
When not in use for a longer period of time, the mic should be stored in a case of some kind. One specific recommendation is to store condenser mics in sealed plastic boxes (like Tupperware) along with a silica gel desiccant pack.

Regular Servicing
Sending in microphones for servicing can help detect potential damage early. Slight soiling can be removed much more easily than a layer of nicotine that has been embedded firmly in the diaphragm. Regular check-ups of microphones on loan or those used in dusty or smoky environments can prove especially beneficial, as the cost is small compared to that of a major overhaul.

Expense of Do-It-Yourself
Attempting your own repairs on a delicate condenser mic can often do more harm than good. For cleaning soiled capsules consider referring the work to a trained and experienced professional.

Also, certain parts of condenser mics may be specifically selected and cannot be replaced with standard components.

Once you’ve invested in a studio con-denser mic, it’s wise to send any defective or damaged microphones directly to the manufacturer or authorized service centers for repairs. These providers can accomplish repairs in a timely, professional manner.

Following the tips in this column and exercising some common sense, you should enjoy a long life of excellent service from your studio condenser microphones.

Karl Winkler is brand manager for Neumann / USA. Contact him at kwinkler@neumannusa.com, or for more information, visit the Neumann Web site at www.neumannusa.com.

Source: DiscMakers.com