Notch Filter: This is a fixed-level, variable-frequency filter for eliminating feedback or unwanted res-
onance. The affected frequency is variable from 40 to 500 Hz. The Notch Filter is effectively turned
off in the full counterclockwise position.
Low battery indicator
Volume Control: Controls the overall gain of the Prefix Plus-T™.
Bass Control: This is a boost / cut shelving tone control for low frequencies.
Contour: This is a wide-range semi-parametric filter. It is used to selectively shape the instrument’s
tone. The Contour Level slider controls the amount of boost or cut applied to the selected contour
frequency. The Contour Frequency slider determines the frequency band that is boosted or cut by
the Contour Level control. The frequency is variable from 250 to 10 kHz.
Treble Control: This is a boost / cut shelving tone control for high frequencies.
Brilliance Control: This is a resonant-style boost / cut filter that adds presence to the sound.
Phase Switch: The Phase Switch compensates for acoustic phase differences that often occur between
instrument and speaker. It can be used as a tone filter at low volume levels or as a feedback filter at high levels.
The Phase Switch can correct any electrical phase difference between the Prefix™ system and
an outboard instrument microphone. Flip the Phase Switch several times and use your ear to find
the optimum setting. The best position for the Phase Switch may change depending on the sound
system and/or venue acoustics.
Contour Frequency: You can scoop out harsh midrange by setting the Contour Frequency slider
slightly above center with the Contour level cut to taste below the center detent. You can also cut
midrange by boosting the Bass and Treble sliders to realize an “implied” mid cut at 800 Hz.
Tuner: The preamp also has a built in chromatic tuner. The display shows the note actually played.
The LEDs beneath the display indicate whether the note is flat (lower red LED), sharp (upper
red LED) or in tune (green LED in the middle). When the tuner is activated, the sound is muted.
The tuner is in true bypass mode when deactivated.
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Alien Acoustic Bass / Alien Acoustic 6-string Bass / Rockbass Alien Deluxe 6-string Bass
Pickups: Fishman Acoustic Matrix
Elektronik: Fishman Prefix Plus-T
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