Using Equalization - Hartke HD75 Owner's Manual

Using Equalization

The Hartkes HD Series Bass Amplifier gives you control over shaping the sound of your
bass, using a process called equalization. To understand how this works, it's important
to know that every naturally occurring sound consists of a broad range of pitches, or fre-
quencies, combined together in a unique way. This blend is what gives every sound its
distinctive tonal color. The HD Series EQ controls allow you to alter a sound by boosting
or attenuating specific frequency areas - they operate much like the bass and treble
controls on your hi-fi amp, but with much greater precision.
The HD75 and HD150 offer three bands of equalization. Each EQ knob, labeled Bass,
Mid, and Treble, affects a different frequency area of the audio. We carefully selected
these frequency areas because they have maximum impact on bass guitar signals. The
Bass and Treble controls are shelving EQs, which provide boost when the control is
moved clockwise from the center or cut when the control is moved counterclockwise
As the Mid control is turned
from the center. The Mid EQ control is a peaking EQ.
clockwise the frequency area is boosted; as it is turned counterclockwise the
frequency area is attenuated.
The seven-band graphic equalizer provides seven sliders, each corresponding to a single
narrow frequency band. This allows you to "draw" the desired tonal response of your
system. When a slider is in its 0, center detent position, it has no effect to the audio
signal. When it is moved above center (towards +12), the particular frequency area is
being boosted; when it is moved below center (towards -15), the frequency area is being
attenuated.
In many instances, the best way to deal with equalization is to think in terms of which
frequency areas you need to attenuate, as opposed to which ones you need to boost. Be
aware that boosting a frequency area also has the effect of boosting the overall signal;
specifically, too much Low EQ boost can actually cause overload distortion or even harm
the connected speaker.
The specific EQ you will apply to your bass signal is very much dependent upon your
particular instrument and personal taste and playing style.
However, here are a few general suggestions:
For reggae or Motown sound, boost the Bass EQ slightly while attenuating the Treble EQ.
To remove boxiness and make your instrument sound more "hi-fi," attenuate the Mid EQ
control.
For a twangy sound that cuts, try boosting the Treble and slighting rolling off the Bass
EQ control.
As you experiment with the EQ controls of the HD Series, don't forget that your bass
also provides significant EQ control in the form of its pickup and tonal settings—this
can be particularly effective in instruments that have active circuitry.
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