Getting Started
Phantom Power (+48v), Pad, & Phase
On the very top of the channel strip (figure 3) you will see a variety of buttons usually consisting of a button for phantom power (48v), which sends external power to your condenser microphones or active DI’s, and a “pad” button which, depending on which console you have, applies approximately a -15dB attenuation to the incoming signal. This is particularly helpful for inputs that have a high gain output (Sometimes basses and guitars will do this.). These two buttons have almost exclusively been included in all consoles I’ve seen. In some cases, an additional “polarity” or “phase” button is included (sometimes noted as 0̸).
Figure 3
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Phase is a phenomenon that occurs between the interaction of two different sound waves. When a sound is produced, it is produced in the form of a sound wave, most often shown as a sine wave (figure 4) . As with microphone pickup patterns, sound waves are described on a 360° graph, where 0 is the beginning of the sound wave, 180° is the center, and 360° is the end (figure 4). What the polarity button does is known as “flipping” the phase. This takes the incoming signal and puts it 180° out of phase, where the beginning of the sound wave is now at 180° (figure 5).
Figure 4
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Figure 5
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There’s a lot more that can be discussed about phase, coherency, polarity, and all it entails, but acoustically, all you really need to know is that sometimes you will run into a situation where you do not have the amount of clarity you would like on your instrument. The polarity button is a tool that, while rarely used, can actually help your instrument achieve a certain amount of clarity. When you press the polarity button, if your instrument sounds clearer, then leave it. However, if you don’t hear any change whatsoever, just keep that button off. I haven’t found too many instances, even in the large settings at Cherry Hills, where the polarity button needed to be used. Even though there were instances (between drum microphones, specifically), these instances were few and far between.