Understanding Your Condenser Microphone Controls

Upon acquiring their first condenser microphone, many folks are immediately befuddled by the various switches and funny looking symbols on the mic's housing (or, on some models, an external transformer box). Those controls are there for a reason-they allow you to alter the mic's pickup pattern, tonality, as well as sensitivity, giving you greater flexibility especially when dealing with louder and/or brighter instruments. Here is a brief primer on condenser-microphone switching, including examples of when to apply the gain attenuator or "pad," bass roll-off, as well as how the different pickup options can be used to good effect.

Pickup Perks
Unlike unidirectional dynamic microphones, a condenser mic uses a dual capsule that is capable of receiving signal from one side (or "cardioid"), both sides ("figure-of-eight"), or all the way around ("omni"). On most models you'll find a three-way selector switch allowing you to choose between the various polar patterns; some mics may even have a fourth, or "super-cardioid," mode. Under normal circumstances you'd use cardioid for a solo vocalist, instrument amplifier or other single source; figure-of-eight for cutting two singers facing each other; and omni for a group of people or to add some room sound, for example. But there can be deviations from these rules-for instance, using omni when recording lead vocals results in an airier, less-direct sound that may be a nice contrast from the standard approach.

Pad Time
Another handy feature on large-diaphragm condensers is the so-called "pad" switch, which reduces (or attenuates) the amount of microphone signal in decibel increments, or generally -5 to -10 or -20 dB. Under normal circumstances such as when recording a lead vocal or an acoustic guitar there's no real need to adjust the pad switch. When miking voluminous instruments such as a snare drum (or an entire drum kit), acoustic piano, electric guitar or bass, this function is incredibly important in that it lets you capture the tone without running the risk of incurring distortion. And with the pad engaged your recording channel has greater headroom, allowing you to run your recorder's pre-amp that much hotter.

Bass Blocker
The other key feature of a condenser mic is its ability to mitigate unwanted lower-end frequencies using a special roll-off switch, also known as a high-pass filter. As the name implies, this circuitry allows higher-frequency sounds to pass through, while simultaneously keeping lower frequencies at bay. For instance, you might try the high-pass filter when recording an instrument such as bass or cello in order to prevent the lowest tones from flooding the mix, improving articulation in the process; you might even use it when tracking a lead vocal to prevent the bass-heavy "proximity effect" from occurring. And because condensers typically have significantly more gain than other mics, the roll-off function can help reject outside noises such as a rumbling furnace, passing vehicles or nearby footfall. Many mics allow you to roll-off anywhere between 40Hz and 175Hz, depending on just how much low-end rejection you require.

Switch It Up
If you mainly work solo recording one track at a time, chances are your mic's "default" setting-cardioid mode, pad and high-pass filter set to neutral-will be good enough for most applications. But with so many different configurations at your disposal, it can't hurt to experiment from time to time, whether it's shaving off 75Hz to achieve an edgier vocal sound, or perhaps switching the mic to omni when recording a dry instrument like shakers or tambourine for a bit of room backsplash.