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Level control
Your next job will be to identify the noise level of the audio.
With the appropriate channel(s) and range(s) selected, pull all six Band Gain
controls and the Level control down fully. Now increase the Level slowly. At first,
you will hear very little happen but, at some point determined by the noise
content of the recording, you will hear the noise disappear. You should attempt to
find the point at which this occurs.
When you place the Band Gain controls in this position, maximum processing will
occur as you increase the Level control, thus making identification of the noise
easier.
Band Gain controls
Once you have chosen the range(s) and determined the Level, you control the
action of the DNS1500’s filter bank using the Band Gain controls.
The six faders represent six frequency bands distributed from lower frequencies
(left) to higher frequencies (right) across the selected range.
You will use the Band Gain controls to control the amount of noise attenuation
performed in each band, adjusting them to suppress as much noise as possible
without introducing unwanted artefacts into the desired signal.
Noise suppression occurs in a given band when the fader is below the 0dB line.
However, there are occasions when you might wish to boost the signal in a given
band, and you can do this by moving the appropriate fader above the 0dB line.
Activity LEDs
The twelve Activity LEDs offer a visual indication of the activity in each of the six
bands controlled by the Band Gain controls.
Both LEDs off:
Less than
±
0.5dB activity
Green LED lit:
The signal is being attenuated
Red LED lit:
The signal is being boosted
The brightness of an LED offers an indication of the amount of attenuation or
boost being applied.
Note that each band controls numerous filters. Therefore, the Activity LEDs in a
given band display the overall activity in that band, and are not necessarily
indicative of the action of any single filter at that moment.
OPERATING THE DNS1500
Introduction
The DNS1500 divides a signal into a large number of well defined bands.
Sophisticated digital filters analyse each of these bands and suppress the noise
independently in each. The innovative design of this filter bank allows you to
control the DNS1500 using relatively few front panel controls.
Bypass
You can route the input directly to the output by pressing the Bypass button. This
allows you to audition the signal before and after processing. The signal latency
is not affected by the Bypass state.
Channel Selector
Your first job will be to identify the channel(s) that include(s) the unwanted noise.
Press the CHAN 1 button if you wish to process channel 1 only. Press the CHAN
2 button if you wish to process channel 2 only. Press both if you wish to process
both channels.
When processing both channels, the DNS1500 uses the same parameter values
for each (as determined by the current settings of the front panel controls) but
responds to the audio in each channel independent of the audio in the other.
Range Selector
Next, you should identify the frequency range or ranges in which the noise lies.
You can press each of the Range Selector buttons individually, or combine them
to choose any one of six possible processing ranges:
Low
20Hz
-
400Hz
Mid
200Hz
-
6kHz
High
4kHz
-
maximum
Low + Mid
20Hz
-
6kHz
Mid + High
200Hz
-
maximum
Full Range
20Hz
-
maximum
The maximum sample rate varies from 12kHz at 32kHz sample rate to
approximately 45kHz at 96kHz sample rate.
To select Low + Mid or Mid + High, press the appropriate two buttons
simultaneously, or in quick succession while the first is flashing. To select Full
Range, press the Low and High buttons simultaneously or in quick succession.
Selecting a range concentrates all of the filters within the DNS1500’s filter bank
across that part of the audio spectrum.
