Starters' Guide To Equalizers; Operation - Omnitronic PEQ-131 Bedienungsanleitung

STARTERS' GUIDE TO EQUALIZERS

At first glance, a graphic equalizer may appear to be a complicated device, but actually, in theory and
operation, a graphic equalizer is a very simple device. Most people are familiar with bass and treble tone
controls. These controls work by dividing the audio signal into two frequency bands - the low frequencies and
the high frequencies. The bass knob, then, effectively becomes a volume control for the lows and the treble
knob gives us volume control over the highs.
"Hz" stands for "Hertz". "KHz" stands for "thousands of Hertz". These are measures of sound-cycles per
second. You see, sound waves are measured by the number of cycles or vibrations they make in one
second. Very low-pitched sounds like bass guitars have far fewer cycles per second than high-pitched
sounds like cymbals. So, if you want to increase the volume of the cymbals in a recording without affecting
the volume of the bass guitar, use the treble control.
The cymbals occupy only a very small band of frequencies within those controlled by the treble control. Also
included in the range of the treble control are vocal sounds. They occupy a similarly narrow band of
frequencies somewhat lower than the cymbals. A treble control alone does not offer enough flexibility of
control to allow us to increase the volume of the cymbals without also increasing
the volume of the vocals. What is needed is a type of control that divides the audio signal, not into two
bands, but as many bands as possible. This would allow us almost unlimited flexibility of control over the
tone "colors" in our audio program.
That's exactly what a graphic equalizer allows us to do. It gives us precise control over the volume of
manynarrow frequency bands, each of which can add (or subtract) their own particular tone "color" to our
overall sound.
In the recording studio and on stage, graphic equalizers are generally used for three distinct purposes:
1.) ROOM EQUALIZATION: Every room adds its own "character" to the sound of music played in it because
of the way the walls, floors, ceilings, furnishings and people absorb or reflect the sound waves. Every room
boosts some frequencies and attenuates others in this way. So graphic equalizers are used, in this context,
to compensate for the "damage" done to the sound by the room itself.
2.) FEEDBACK CONTROL: Without a graphic equalizer, it is quite difficult to stop feedback (that piercing,
whistling sound that happens when microphones pick-up and reamplify the sound from the speakers). A
graphic equalizer can zero in on the offending frequency and reduce it, leaving the rest of the music
unchanged.
3.) CREATIVE RECORDING: Graphic equalizers are routinely used to make certain sounds "brighter" or
"fuller" or even radically different, depending on the creative whims of the operator. A voice can be made to
sound as though it's coming through a telephone line, for example. An acoustic guitar can be given a metallic
sparkle. A kick drum can get more "snap". It may be a cliché, but it's true: With a graphic equalizer, you are
only limited by your own imagination!

OPERATION

Frontpanel:
1) POWER SWITCH Turns power to the equalizer on and off. Be sure to power-up before your power
amplifier is turned on to avoid loud transients which could damage your speakers or annoy your audience.
2) FREQUENCY FADERS Moving these sliders upward boosts their labelled frequency bands, and moving
them downward cuts (decreases) them. When moving these controls past zero, you will feel the center-
detent (notch) in the control which makes it very easy to find zero in a hurry, or even in the dark.
3) EQUALIZER RANGE SELECTOR SWITCH WITH L.E.D. One of the reasons to use a graphic equalizer
is that the frequency sliders themselves form a graphic depiction of the frequency response curve you have
set. But if your settings are very subtle, the "graph" becomes difficult to set and see. If you encounter this
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