Equalizers; What Is An Eq - PRESONUS STUDIOLIVE 16.4.2 - V1.12 User Manual

5 Tutorials

Equalizers

5.4
The StudioLive is equipped with a 4-band semi-parametric equalizer on every input and output bus.
Here's a brief explanation of how an EQ functions, as well as some charts to help you navigate the
frequency ranges of various instruments so you can quickly choose the best EQ settings for your
recordings and live mixes and to help you get the most out of your StudioLive.

What is an EQ?

5.4. 1
An equalizer is a filter that allows you to adjust the level of a frequency, or range of frequencies, of
an audio signal. In its simplest form, an EQ will let you turn the treble and bass up or down, allowing
you to adjust the coloration of, let's say, your car stereo or an iPod. In recording, equalization is a
sophisticated art. Good equalization is critical to a good mix.
When used correctly, an equalizer can provide the impression of nearness or distance, "fatten" or
"thin" a sound, and help blend or provide separation between similar sounds in a mix allowing them
to both shine through the mix.
The Parametric EQ
The Parametric EQ and semi-Parametric EQ are the most common equalizers found in recording
and live situations because they offer continuous control over all parameters. A parametric EQ
offers continuous control over the audio signal's frequency content, which is divided into several
bands of frequencies (most commonly three to seven bands). A fully parametric EQ offers control
over the bandwidth (basically, the range of frequencies affected), the center frequency of the band,
and the level (boost/cut) of the designated frequency band. It may also offer separate control over
the Q, which is the ratio of the center frequency to the bandwidth. A semi-parametric EQ, like those
in the StudioLive, provides control over most of these parameters but usually the bandwidth is
fixed.
The Q
Although a semi-parametric EQ such as those in the StudioLive does not provide a continuous
bandwidth control, it offers an indirect way of switching between wide and narrow bandwidth: the
Hi Q switch. Q is the ratio of center frequency to bandwidth, and if the center frequency is fixed,
then bandwidth is inversely proportional to Q—meaning that as you raise the Q, you narrow the
bandwidth. (In fully parametric EQs, you have continuous bandwidth control and/or continuous Q
control, rather than a high/low Q switch.) This allows you to attenuate or boost a very narrow or
wide range of frequencies.
A narrow bandwidth (high Q) has obvious attenuation benefits for removing unpleasant tones. Let's
say the snare drum in your mix has an annoying ring to it. With a very narrow bandwidth, you can
isolate this one frequency (usually around 1 kHz) and remove, or reject, it. This type of narrow band-
reject filter is also known as a notch filter. By notching out the offending frequency, you can remove
the problem without removing the instrument from the mix. A narrow bandwidth is also useful in
110