Equalization: How to use EQ

EQ (Equalization) is an important tool in creating the ideal sound recording. However, like any tool, it has a specific function and is not ideal for all situations. EQ is not even a required resource for sound quality. If the microphone did not pick up sound properly while recording or a music sample of poor quality was imported, then EQ is not going to magically give the perfect sound. But even an excellent sound recording may require the use of EQ in order to help the artist produce the best piece possible. In addition, EQ is also useful for adjusting sound quality in order to make it more realistic. While considered a very technical aspect of sound editing, EQ has an artistic side as well. It can be used creatively to intentionally create distortion, or to enhance the spectrum of sound available on a recording.

EQ Terms
It is often helpful to measure EQ when working on developing sound quality, especially when just learning the ropes of sound recording and EQ. If the initial sound quality is strong, a flat response will be seen, and as work with the EQ progresses, curves will develop to show how the quality is modified. Curves help illustrate two types of EQ: peaking and shelving. Peaking EQ is described perfectly by the bell shaped curve. Shelving EQ, on the other hand, is demonstrated by a curve that is not bell shaped. Shelving occurs when boost extends from the initial frequency to the extremes of the said frequency range. Both types of EQ have their own merits, and which one to use depends on the kind of effect that the user wants to achieve with the sound. 

EQ Doesn’t Fix What is not There
EQ does not create sound quality, but instead helps to perfect the level of quality. Specifically, the tool works with the frequency balance of a sound. This allows showcasing specific aspects of a sound while downplaying others. Because editing EQ alters the sound level, the fader needs to be adjusted in later steps of the editing process to compensate for the change.

Start at Zero
When first beginning to use EQ in sound editing, it is important to have the EQ set to zero. It is also necessary to know what to fix, accentuate, or hide before actually starting the EQ process. In order to emphasize a certain sound, boost its strong frequencies by setting gain to have a medium level of boost, and then play with the control limits until the strongest sounds are heard.

EQ Cut
Downplaying a particular sound is called an EQ cut. The EQ cut is not commonly utilized during sound editing, although it is very helpful in decreasing the individuality of a particular voice or instrument. To perform an EQ cut, find the particular sound’s strong frequencies, and then cut them.  Note that the cut should only have a thin bandwidth so as not to remove too much and risk damaging the overall sound of the recording.
Frequency, Gain and Q
EQ controls three aspects of sound: frequency (boost), gain (degree of boost), and Q. Q is the measure of width of the bell curves that develop when working with EQ. It controls the bandwidth of a sound. This allows the user to find and modify specific aspects of a sound, instead of the entire combination of frequencies.

Outboard EQs
While EQ is available on most mixing consoles, an external EQ unit can provide additional features. Referred to as outboard EQs, there are two kinds: graphic and parametric. Graphic EQs have sliders organized according to pre-set frequencies, and these frequencies are not normally changeable. Graphic EQs provide an estimate of the curve that develops as the sound is edited, although they are not completely accurate or precise. The parametric EQ is more useful, as it is able to control frequency, gain, and Q all at the same time. They are also better in terms of precision and accuracy, as they can handle a wider range of frequencies than a graphic EQ.
Not a Magic Wand, But…
Although EQ is not a magic wand to fix poor-quality sound, it occasionally can be helpful. For example, it can minimize an unwanted buzz that appears on the recording. This will, however, somewhat deplete the musical sounds on the recording, but the loss will be minimal, considering the overall gain in quality. A graphic EQ will work best for solving this problem, as it is excellent for shaping a whole piece of sound, even if that piece has many different elements. However, a parametric EQ will also work, as it can use the Q factor to locate the particular annoying frequency. This can be accomplished by sweeping the boost across frequencies in order to find the (un)desired sound. Then remove the frequency by making an EQ cut.

In the event that a recording is mixed too high, an EQ can be used to cut offending noise or to boost lower frequencies to create a balance. However, as when fixing excess sounds, there will be a slight decrease in sound. It is nearly impossible to fix such problems without some sort of minor negative effect to the original recording.

EQ Distortion
One of the problems that can be encountered when using EQ is unintentionally creating sound distortion. Should this problem arise, reducing the gain should repair the problem. It is also possible to use too much EQ to the sound. This can normally be avoided by simply paying attention and listening while working on the recording. However, the problem can be fixed on a finalized sound by boosting other frequencies to create a balance. Once again, though, some detriment to the overall sound is to be expected.

Other Uses
The techniques in using EQ to improve the sound quality of a piece can also be used for more creative purposes. For example, the instructions given on how to locate and showcase a particular sound can also be used to over-emphasize that sound, if that is the musical preference of the user. In addition, it should be noted that these techniques are applied to using EQ on sound that has already been recorded. However, EQ can also be used during the recording process to accentuate (or tone down) the sounds produced by particular voices or instruments.