Groove Tubes: Caring for Microphones

High-quality condenser mics like the Groove Tubes line represent an investment. A few basic tips will help insure a lifetime of excellent performance.

Pop Filters and Windscreens

Vocalists exhibit “plosives” in the form of “p”s, “t”s and “b”s that project extra energy toward the microphone. With that extra energy comes unwanted pops in the sound, as well as saliva—another form of moisture that is not healthy for a condenser mic. For these combined reasons, a pop filter is highly recommended when recording vocals with condenser microphones. Typically a thin mesh stretched over a circular frame, the pop filter is mounted between the vocalist and the mic capsule. (In a pinch, you can even construct a pop filter with a hanger and pantyhose.)

Windscreens, as the name implies, are sometimes used in outdoor recordings in order to reduce wind noise and particulate matter striking the diaphragm. Windscreens typically consist of a thickness of foam custom designed to fit over the capsule. Windscreens can reduce both low and high frequency response, so they are typically not used as substitutes for pop filters.

Shock Protection

As we’ve seen in previous columns, condenser mics are constructed with extremely thin diaphragms and very high tolerances. As such, condensers should be protected from abuse, especially physical shock. (Groove Tubes capsules are rubber-mounted internally, but caution still applies.) Keep condenser mics away from situations in which they might be physically abused. Unlike a dynamic microphone, condensers should always be mounted on a stand, rather than hand-held (let alone swung around at the end of a mic cord by a vocalist exhibiting showmanship). Similarly, wayward drum sticks, guitar necks, violin bows and the like are not friends of condensers. As indicated earlier, condensers should only be used live in controlled situations where the stage is protected from the elements and is the exclusive domain of professionals. Needless to say, you want to take great steps to avoid dropping a condenser or knocking over a mic stand holding one. Duct-taping cables down in order to avoid tripping is recommended.

A soft mount—one that suspends the mic in an elastic web—is usually desirable because the mount absorbs vibrations from the floor, passing trucks or airplanes, and any modest inadvertent physical shock. While hard mounts provide no such shock absorption, they are sometimes useful in tight situations or when exact placement is required, such as in an X-Y stereo miking configuration.

Temperature and Humidity

The thin diaphragms and tight tolerances of condenser microphones make them susceptible to temperature and humidity extremes. Never use condenser microphones when there is risk of water damage (such as rain). Avoid high humidity situations such as seaside climates lacking air conditioning.* The operating temperature of most condensers is 50ºF to 95ºF. If a condenser has been outside in a colder environment (such as transporting it in winter), allow the mic to slowly acclimate to room temperature before applying power in order to avoid condensation on the capsule. Similarly, be careful not to leave condenser mics to bake in the trunk of your car on a hot, sunny day. These same precautions apply to tube power supplies as well.

*Tip: Even the best condenser will start producing a crackling noise if inadvertently exposed to too much humidity. In this event, an old trick is to place it near the heat of a light bulb for about half an hour.

Cleaning and Storage

Always store a condenser microphone in its case when not in use. Particulate matter such as dust can attach itself to the diaphragm and cause degradation of performance over time.

In most cases, wiping the metal exterior of a microphone down with a dry or slightly damp rag will be sufficient to remove dust, dirt, fingerprints and the like. In the event that further cleaning is necessary, spray a non-abrasive household cleaner such as Fantastik or Formula 409 onto a rag and wipe the metal exterior with the rag. NEVER spray directly onto the microphone as it may damage the capsule. NEVER attempt to clean the inside of a microphone. If performance degrades, contact M-Audio for factory repair.

This story is excerpted from our free Record Now: Choosing and Using Microphones guide, which covers microphone technology and techniques. It’s available either via download, or at your local M-Audio dealer.

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