Fishman Loudbox 100 User Manual

14
About Acoustic Feedback
Feedback usually occurs in the lowest
octave of your instrument, generally with
two notes about a half step apart. The
lower type of feedback (cavity reso-
nance) starts when the sound pressure
coming out of the speakers excites the
resonant air chamber inside your instru-
ment. We have found that it is effective
to tune out an instrument’s cavity reso-
nance feedback with the Anti Feedback
(notch fi lter) in the Loudbox 100. For
acoustic guitar this occurs at G# on the
low E-string, or at about 100Hz. Turn the
Anti Feedback knob to about 11 o’clock
to dial out this resonance. Note that
the circuit can be effectively defeated
by moving the dial to the Off (7 o’clock)
position.
The higher range of feedback (top
resonance) usually starts about a half or
whole step above cavity resonance of
the instrument. Top resonance feedback
happens when the sound pressure
coming off the speakers excites the
resonant frequency of the soundboard
of your instrument. For acoustic guitar
this occurs at A and above on the low
E-string. Push the Phase switch in and
out until you fi nd the position that
subdues top resonance feedback.
Lower
Feedback Range
(E to G#)
Upper
Feedback Range
(A and above)
OFF
Anti
Feedback
Phase

Fishman Loudbox 100 Specifications

General

Brand	Fishman
Model	Loudbox 100
Category	Musical Instrument Amplifier
Language	English