The two primary features available on a microphone are a PAD and a roll-off. Not all microphones are manufactured with these features, but they exist on many kinds of mics and are important to understand.
PAD is an acronym for “Passive Attenuation Device.” A PAD softens the sensitivity of the capacitor inside of the mic, allowing it to record louder signals and performances without distortion. The number rating (eg -20dB PAD) is the strength of the PAD, measured in decibels. The higher the decibel rating, the stronger the PAD.
A roll-off is a high-pass filter built into the microphone. The roll-off will dramatically soften the low-end frequency response of a microphone and is useful for decreasing or removing rumble from a recording, especially if the studio does not have a floated floor. The numerical value next to the roll-off represents the frequency at which the high-pass filter begins. Pictured below is an 80Hz roll-off.
When used properly, these features enhance the microphone’s performance. For example, a PAD is unnecessary when a loud source is not creating any distortion in the signal chain and a roll-off should not be used when the source is a low frequency-producing piece of instrumentation (like a kick drum).
The polar pattern is the area of the room that the microphone is recording. It can also be referred to as the “directionality” of the mic. There are five main polar patterns, each with its own directionality: cardioid, supercardioid, hypercardioid, figure 8 and omnidirectional.
The cardioid pattern is the most directional. A cardioid mic focuses on the source placed in front of it and rejects signals behind it (referred to as the “null point”). This makes cardioid the go-to pattern for vocals.
Supercardioid slightly extends the polar pattern behind the mic, making it desirable to capture a small amount of room tone with the source. Hypercardioid is even wider behind the mic, capturing even more room. Make sure the room you are using sounds good if these patterns are used!
Figure 8 patterns capture evenly from the front and rear of the mic, with null points on the sides. This is ideal for any application that needs a bit of air to breathe in the room behind the mic (like a guitar amp) or for group chants/background vocals when a discrete track for each voice is not needed.
An Omnidirectional pattern records equally in the 360 degree area surrounding the microphone. Needless to say, the sound of the room is very prevalent with an omni mic. This pattern is commonly used for microphones that are a good distance from a drum kit, capturing the air being pushed from the drums into the room.
Multi-pattern microphones are a flexible resource to have in a recording space, but remember to keep your objective and positioning in mind. I often say “consider the pattern,” meaning consider the polar pattern and the microphone’s position against the instrument in order to achieve the best recording possible.