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The BackDrop algorithm occupies:
@ Normal Sample Rate : 1/4 DSP Resource
@ Double Sample Rate : Not available
Algorithm Inputs/Outputs are distributed as follows:
E1 - E4
L
R
L
R
INPUT
OUTPUT
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Main
BackDrop’s main screen allows you to set certain global
parameters.
Algorithm Model
Allows you to select between the Basic, MultiBand and
MultiType algorithm models. These models are described
below in detail. You can instantly switch between models at
any time and the settings for each model are recalled.
Processing Mode
The Processing Mode control allows you to alternate
between BackDrop’s two modes of operation - Stereo
or M/S (mid/side). In Stereo mode, BackDrop assigns a
separate noise reduction process to the Left and Right
channels while in M/S mode, BackDrop assigns a noise
reduction process to the Mid signal and another to the Side
signal. For certain stereo audio sequences, operating in
M/S mode can give better results than when operating in
Stereo mode. It should be noted that when you change the
Processing Mode, BackDrop automatically recalculates the
noise print information for the current operating mode.
Left and Right Input Trim
The Left and Right Input Trim controls allow attenuation of
the incoming signal level. The left and right signals can be
independently attenuated by as much as 12 dB. In order
to get the maximum internal processing resolution from
BackDrop, the Input Trim controls should be set to 0 dB.
Status
On the right side of the screen is a panel which is visible
on all of BackDrop’s screens. At the top of this panel is a
region which displays the status of the noise print (No print,
Calculating, Running or Error). In order for BackDrop to
operate properly, the word “Running” must appear in the
status window, indicating that a valid noise print is available.
If “No Print” appears in the status window, then you have not
yet captured a valid noise print. If the word “Error” appears
then the sampling rate has changed since you captured your
noise print.
Introduction
The BackDrop noise reduction system was designed to
provide the maximum amount of noise reduction without
audibly altering the underlying signal. Since noise removal
systems can also remove part of the signal, BackDrop’s
fundamental philosophy is to remove the noise with as little
processing as possible. That is, BackDrop monitors the
incoming signal and continuously decides the perceptually
optimal processing to apply. This is accomplished using
advanced mathematical algorithms resulting from more
than seven years of research. BackDrop’s three patented
algorithm models allow you to apply the processing with
surgical precision while leaving the music undisturbed.
BackDrop lets you choose the algorithm model that best
suits the noise you want to reduce.
BackDrop’s Basic model provides a simple set of controls
that are perfect for removing common broadband noises
such as tape hiss. The MultiBand model expands your
control by allowing you to divide the noise reduction
process into three independent frequency bands. This
gives you full control to shape the noise reduction across
frequency in such a way that you can maximize the
noise reduction without damaging the signal. Finally,
the MultiType model separates the noise into three
components (Buzz, Room, and Hiss) and lets you choose
how much of each noise component to reduce.
BackDrop was specifically designed to remove noises
found in today’s world (hums and buzzes, room rumble, air
conditioning systems, tape hiss, etc.) and is not intended to
be used for removing clicks and pops.
As an integral part of each of its three algorithm models,
BackDrop includes a complex model of the human auditory
system. BackDrop continuously listens to the incoming
signal and removes only the parts of the noise that the ear
can hear. BackDrop offers two unique controls (Basilar
Dispersion and Transient Recovery) to adjust certain
parameters in the ear model. The ear model is another key
component in BackDrop’s philosophy of applying as little
processing as possible to the incoming signal so that only
the noise is removed, not the music.
