Rivera Sedona Owner's Manual page 8

Presence
The Presence control is incorporated as a vital part of the power amp section. Think of
it as a final brightness control after all the EQ, distortion, effects, and reverb.
Anti-Feedback Equalizer
This works with both channels simultaneously
The Sedona Lite is provided with a special circuit that can reduce the tendency or amount of
resonant feedback that commonly occurs when amplifying acoustic instruments. This is possible by
enabling a dip or cut in the frequencies that are amplified, with the frequency and amplitude of the
dip continuously variable (like a parametric equalizer). The design parameters of this "cut-only"
equalizer were chosen for their musical and sonic qualities.
It may also be desirable to use this feature for additional equalization to work in tandem with a
Channel's passive 3-band (Treble, Middle, Bass) controls. For instruments that may have an
excessively fat or midrange tone, you can select a deeper midrange notch.
Anti-Feedback Level (with Pull On switch)
To activate this feature, pull out the knob on the control labeled Level located in the right area of
the front panel. An adjacent red LED will illuminate, indicating that the circuit is engaged. Rotating
this control adjusts the level of "cut," or "dip," with 1 providing the minimum cut and 10 providing
the maximum cut.
Anti-Feedback Frequency Control
Rotating this control with the Anti-Feedback equalizer engaged continuously sweeps the different
center frequencies of the "cut," or "dip." The knob setting of 1 corresponds to the narrowest range
(150 Hz) and 10 correspond to the widest range (3.5 kHz).
P U
RACTICAL
A. For controlling feedback
controls to taste. When a note or frequency begins to drone or howl, indicating feedback,
turn on the equalizer and rotate the Level knob to 10. Then rotate the Frequency knob until
you find the setting that tunes out the note or frequency that is feeding back. Now try
lowering the "cut" amount by decreasing the equalizer's Level control until the feedback
comes back. Now slightly increase the amount of "cut." By minimizing the Equalizer's
"cut," you minimize the effect it has on the overall tone. The most effective adjustment of
this equalizer is a matter of taste, and varies according to the type and size of your
instrument, Channel 1 or 2's volume and tone settings, room acoustics, and your demands.
B. For additional EQ
so you may want to adjust your sound using the Anti-Feedback equalizer. For example, typical
O T A
SE F HE NTI
When the equalizer off, adjust the volume and tone
Some instruments require more midrange notch, or "cut," than others,
-F E
EEDBACK QUALIZER