Mute Button - Roland AC-90 Guide D'utilisation

Setting the Feedback Point Automatically
This automatically detects the frequency at which feedback
occurs and suppresses feedback.
* Use in conditions where feedback occurs.
1. Cause feedback whine to occur.
2. Turn the FREQUENCY knob to the "AUTO" position.
fig.033
The ANTI-FEEDBACK indicator flashes slowly, and
automatic detection goes into standby.
3. Press the START button.
Automatic detection of the feedback point starts. The indicator
flashes rapidly when detection is in progress, and when the
feedback point is found, the indicator lights steadily. If no
feedback point is detected, the indicator flashes slowly, and
the automatic detection function returns to standby.
4. Press the START button once more to conduct the
automatic detection again.
Setting the Feedback Point Manually
1. Cause feedback whine to occur.
2. Turn the knob, moving through the range of L through
H (the ANTI-FEEDBACK indicator lights up) to search
for the frequency at which the feedback is to be
suppressed.
fig.34
Turning the knob clockwise suppresses progressively more
treble feedback, and turning it counterclockwise suppresses
progressively more bass feedback.
You can use a foot switch (the optional BOSS FS-5U, FS-6) to
run automatic detection of the feedback frequency or to turn
the anti-feedback function on and off.
You can use anti-feedback even when feedback is not a
problem. For example, you can use it to remove undesirable
resonance in the low to midrange, as well as correct other
problems with the sound quality.
Names of Things and What They Do

15. MUTE Button

This switches the Mute function on and off.
When you press the button, the MUTE indicator flashes,
muting is turned on, and the speaker output and sounds
from SUB WOOFER OUT and LINE OUT are muted.
With the mute function activated, you do not need to turn
down the VOLUME knob or MASTER knob to mute the
noise when plugging into, or unplugging from your guitar.
* Sounds from the DI OUT/TUNER OUT and PHONES jacks
are not muted.
By connecting a tuner (optional) to DI OUT/TUNER OUT
and then pressing the MUTE button, you can tune your
instrument without the sound being output from the
speakers.
You can use a foot switch (optional BOSS FS-5U or FS-6) to
switch muting on and off. (p. 13)
16. MASTER Knob
Adjusts the overall volume level.
* LINE OUT cannot be adjusted.
17. PHONES Jack
Headphones are connected here. No sounds are output from
the speakers or from SUB WOOFER OUT when headphones
are connected.
18. POWER Switch
This turns the AC-90's power on and off.
The POWER indicator lights up when the power is on.
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* If you need to turn off the power completely, first turn off the
POWER switch, then unplug the power cord from the power
outlet. Refer to Power Supply (p. 5)
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* Due to a circuitry protection feature, this unit requires a few
moments after it has been turned on before it is ready for
normal operation.
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* Always make sure to have the volume level turned down before
switching on power. Even with the volume all the way down,
you may still hear some sound when the power is switched on,
but this is normal, and does not indicate a malfunction.
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