Hartke HA4000 Mode D'emploi page 8

Guided Tour - HA4000 Front Panel
6. DBASS control - This unique harmonic enhancer adds ultra-low frequencies ("Deep
Bass") to the output of the HA4000. As you move the knob clockwise, more and more of
this signal is added (up to 12 dB). When set to 0, no Deep Bass signal is added.
7. Low EQ control - This control provides approximately 15 dB of cut or boost at 140 Hz,
with a peak (bell) curve. When the knob is at the 12 o'clock ("0") position, there is no
boost or attenuation (flat response). As it is turned clockwise from the "0" position, the
frequency area is boosted; as it is turned counterclockwise from the "0" position, the
frequency area is attenuated. For more information, see the "Using Equalization and
Shape" section on page 11 in this manual.
8. Mid Low and Mid High EQ controls - These controls provide two bands of fully
parametric equalization for total customization of the HA4000 to match your instrument,
selected speaker, and style of playing. Approximately 15 dB of cut or boost are available
for each band. When the "Mid Low" or "Mid High" knob is at the 12 o'clock ("0") position,
there is no boost or attenuation (that is, flat response). As it is turned clockwise from the
"0" position, the selected frequency area is boosted; as it is turned counterclockwise from
the "0" position, the selected frequency area is attenuated. The frequency of the Mid Low
control can be swept between 40 and 400 Hz, while the frequency of the Mid High control
can be swept between 300 Hz and 6 kHz. Each band also has an associated bandwidth
control. As this is turned clockwise, the width of the equalization curve is narrowed and
only a small frequency range is affected; as it is turned counterclockwise, the width of the
equalization curve is expanded and a greater frequency range is affected. For more
information on the use of these controls, see the "Using Equalization and Shape" section
on page 11 in this manual.
9. High EQ control - This shelving control provides approximately 15 dB of cut or boost
at 5 kHz. When the knob is at the 12 o'clock ("0") position, there is no boost or attenuation
(flat response). As it is turned clockwise from the "0" position, the frequency area is
boosted; as it is turned counterclockwise from the "0" position, the frequency area is
attenuated. For more information, see the "Using Equalization and Shape" section on
page 11 in this manual.
10. Status LEDs - The bottom "Power" LED lights whenever the HA4000 is powered on
(see #11 below). The top "Clip" LED lights whenever the output signal rises to an
unacceptably high distortion level. The center "Protection" LED goes on for approximately
five seconds when the HA4000 is powered on and fades slowly when it is powered off.
While it is lit, all connected speakers are muted via mechanical relay, thus preventing any
"thump" from occurring.
11. Power switch - Use this to power the HA4000 on or off.
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