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D3500 Quick-start
Quick start –
Using the D3500 to Reduce Feedback
The D3500 is a powerful 30 band, fully parametric equal-
izer with onboard loudspeaker processing effects. Each
of the 30 filters can be manually set and all the effects
parameters can be adjusted and stored into memory.
However, if you want to use the D3500 as a simple auto-
matic feedback management system, you can. First, lets
look at some basic concepts to employ that will help
reduce the chance of feedback before you even power up
the D3500.
Microphone Positioning - How to Reduce Feedback
Feedback is the annoying howling and squealing that is
heard when the microphone gets too close to the speaker
and the volume is high. You get feedback when the micro-
phone picks up the amplified signal from the speaker, and
then amplifies through the speaker again, and then picks
it up again, and so on and so on. In general, it is always
recommended that any LIVE mic (a mic that’s on) is posi-
tioned behind the speaker enclosures. This will give you
the best level from your system before feedback. One
possible exception is when you are adjusting the sounds
of the microphones, since you want to listen in front of the
speaker to hear properly. To do this, lower the PA system' s
main volume while setting the EQ and effects from in front
of the speakers. Once you have the sound you like, move
the microphones to behind the speakers and raise the
Main volume. In addition, be aware of your microphone's
pick up pattern. For most live sound applications, a uni-
directional or Cardioid microphone with great rear rejec-
tion is the best solution for getting the most gain before
feedback.
Looking for a great dynamic mic with above aver-
age feedback rejection? Try a Samson Q7.
Speaker Placement
Whenever possible, it is a good idea to raise the speakers
above the heads of the listening audience. Any good loud-
speaker, like the Samson dB500, Expedition, or Resound
model enclosures, feature a standard 1 3/8” pole mount
receptacle, which is compatible with speaker stands from
a variety of manufacturers (including the Samson TA100).
Position your speakers for the best audience coverage, but
be aware of where your live mics will be during the course
of your performance or presentation and position the
speakers in front of the live stage area.
Using the D3500 for Automatic Feedback Managemet
The following example is for reducing feedback in a typi-
cal PA system used by a band in a small to medium size
club using the D3500. First you’ll set ten of the filters to
RESONANCE mode to remove problem frequencies that
occur due to microphone and monitor placement, as well
as those caused by room acoustics. When the filters are set
to Resonance the D3500 will detect a feedback problem,
then set automatically the filter to the feedback frequency,
and then lock on that frequency until it is reset or a new
program is preset loaded. After setting the RESONANCE fil-
ter, you’ll set some additional filters to DYNAMIC mode to
handle feedback problems that occur from artists moving
around on stage with their microphones. When the filter is
set to DYNAMIC mode, it will search for feedback and then
lock on that frequency until the feedback problem goes
away. If the filter set to DYNAMIC senses that the feed-
back problem is no longer present, it will begin to search
for new feedback problems. So, by setting some filters to
Resonance and some to Dynamic, you can easily handle
feedback problems from speaker and mic placement, as
well as from presenters and performers moving around
with live mics. Simply follow these basic steps and start
getting a louder mix without feedback.
• Using standard XLR cables, connect the output of your
mixer to the D3500's rear panel XLR INPUT connectors.
• Now, run another set of XLR cables and plug the D3500's
rear panel XLR OUTPUT's to your power amp or active
speaker inputs.
Note: If you are using any other signal processors like a
graphic equalizer or compressor, put the D3500 after them in
the signal path.
• Power up your system as normal.
• Press the D3500's LINK switch so that the green LED
lights, indicating the left and right channels are linked
together.
• Press the BYPASS switch so that the LED is off, indicating
the D3500’s digital processing effects are engaged.
• You’ll probably want to start with a default preset, so
press the LOAD switch. The LED will flash indicating the
D3500 is ready to load a preset.
• Use the Data Wheel to select Preset 00 and press LOAD.
• Now, select the first ten filters by pressing and holding
the Channel 1 Filter Select Switch, and then press the
Channel 10 Filter Select Switch. At this point you will
notice that the green Selection LEDs for the filters 1 – 10
are lit. This indicates that the filters are ready to be set-
up and engaged.
• To set these filters to RESONANCE mode press the EQ
switch until MODE is displayed in the main LCD.
• Use the Data Wheel to select Mode 3; (RESONANCE).
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