Using Equalization

The Hartke Systems A Series Bass Amplifier gives you enormous 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 frequencies, combined together in a unique way. This blend is what gives every sound its distinctive tonal color. The A 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 A 25 and A35 offer four bands of equalization. Each EQ knob (labeled Bass, Mid, Treble and Bright, respectively) affects a different frequency area (100 Hz, 830 Hz, 5 kHz and 8 kHz, respectively) and provides approximately 15 db of boost and attenuation except for the Bright control which provides 0 -20 dB of Boost only. We carefully selected these frequency areas because they have maximum impact on bass signals. For example, the Bass (100 Hz) control affects the very lowest audible frequencies (in fact, most humans cannot hear below 20 Hz), while the High (5 kHz) control affects the “twang” of a bass string.

 

BASS

 

 

MID

 

TREBLE

 

BRIGHT

 

0

 

 

0

 

 

0

 

 

5

-3

+3

 

-3

+3

 

-3

+3

 

4

6

-6

 

+6

-6

 

+6

-6

+6

3

 

7

-9

 

+9 -9

 

+9 -9

+9 2

 

8

-12

 

+12

-12

 

+12

-12

+12

1

 

9

-15

+15

 

-15

+15

 

-15

+15

 

0

10

 

100Hz

 

 

830Hz

 

 

5K

 

 

8K

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. Turning all EQ controls up the same amount will have virtually the same effect as simply turning up the Volume; conversely, turning them all down the same amount will have virtually the same effect as turning down the Volume. Both approaches are pointless (after all, that’s why we gave you a Volume control!)

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.

10