Using Equalization

One of the most exciting aspects to using a mixer such as the MPL 1640 is hav- ing the ability to shape a sound, using a process called equalization. But there are few areas of sound engineering more misunderstood than equalization, and, just as good EQ can really help a sound, bad EQ can really hurt it, so read on...

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Every naturally occurring sound consists of a broad range of pitches, or frequen- cies, combined together in a unique way. This blend is what gives every sound its distinctive tonal color. The EQ section in a mixer allows you to alter a sound by boosting or attenuating specific frequency areas. The MPL 1640 provides independent three-band equalization controls for each of its sixteen channels. The “High” knob affects frequencies in the 10 kHz area; the “Mid” knob affects frequencies in the 800 Hz area; and the “Low” knob affects frequencies in the

80 Hz area. Each EQ knob is labeled with the maximum amount of cut or boost provided (±15 dB in the case of high and low frequencies, and ±12 dB in the case of the mid frequency).

We provided these particular frequency areas because they have maximum impact on musical signals—that’s why they are sometimes known as “sweet spots.” When an EQ knob is in its center detented position (“0”), it is having no effect. When it is moved right of center, the particular frequency area is being boosted; when it is moved left of center, the frequency area is being attenuated. The high and low EQ controls employ what is known as a shelving curve (where frequencies either above or below the specified area are affected, respectively) while the mid frequency control employs what is known as a bell curve (where frequencies both above and below the specified area are affected).

In most instances, the best way to approach equalization is to think in terms of which frequency areas you need to attenuate, as opposed to which ones you need to boost (boosting a frequency area also has the effect of boosting the overall signal; too much EQ boost can actually cause overload—with the accom- panying Peak LED warning!). Be aware of the phenomenon of masking, where loud sounds in one frequency range obscure softer sounds in the same range; by cutting EQ “notches” in a loud signal, you can actually make room for a softer one to shine through. And try not to think of EQ as a miracle worker—no amount of equalization can put a singer in tune or remove the distortion from an over- loaded input signal! The key is to get the signal right in the first place, by using correct gain structure and mic placement.

Although the specific EQ you will apply to a signal is very much a matter of personal taste, here are a few general suggestions: Boosting the low frequency of instruments such as bass drums or bass guitar will add warmth and make the sound “fatter”; conversely, you may want to attenuate the low frequency compo- nent of instruments such as cymbals, high-hats, and shakers so as to “thin” them out. The mid-range control is particularly effective for vocals—attenuating it can give a vocal performance more of an “FM-radio” feel, while boosting it can help a vocal cut through dense instrumentation. Be careful not to boost high frequen- cies too much or you risk adding hiss to the signal, though just a touch can help add “shimmer” to an acoustic guitar, ride cymbal, or high-hat. Finally, because both the high and low EQ settings are shelving controls, you can use them to reduce hiss (by attenuating high frequencies) or rumble (by attenuating low frequencies).

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Samson MPL 1640 manual Using Equalization