Sonnox
Prior to the digital revolution, noise was a
by-product of the physical media used to
store music – remember the crackle of records
and the background hiss of cassette? The
transition to digital consumer formats banished
such physicality-related artifacts, but noise is
still very much a concern when recording.
Background hum and noise can contaminate
recorded parts, and can be caused by dodgy
cables or grounding issues, or electrical clicking
from devices on the same mains circuit (kettles,
fridges, etc). Video can sufer to the point where
dialogue is masked by wind or motor noise from
the camera, and of course, material transferred
from tape or vinyl may very well still sufer from
the artifacts mentioned earlier.
Noise pollution
To combat noise problems post-recording, or to
restore audio sourced from elderly formats, we
can turn to noise reduction software such as
Sonnox’s Restore suite. It features three plug-ins
– Oxford DeClicker, DeBuzzer and DeNoiser –
which are designed to suppress clicks, pops,
crackles, scratches, hums, buzzes and noise.
Restore can work at up to 96kHz, and if you
need to use more than one plug-in, Sonnox
advise placing the DeClicker irst, then the
DeBuzzer and/or DeNoiser, depending on which
nuisance elements are most prevalent.
DeClicker ofers three sections, De-Pop,
De-Click and De-Crackle, dealing with noise
events of durations up to 10ms, 3ms and 0.4ms
respectively. Each section has its own threshold
and sensitivity controls, for dialling in optimal
detection. Once this is done, DeClicker’s
algorithms distinguish between noise events
and audio content, the former showing up as
colour-coded dots on the graphical display. With
some types of material (eg, distorted guitars),
the DeClicker can falsely lag up wanted audio
events as clicks or crackles, but that’s easily
solved by utilising the Exclude Box function – a
scalable box that you draw on the main
graphical display to exclude events within a
certain duration/level range from processing.
You hum it, I’ll erase it
DeBuzzer ofers hum and buzz removal, and
operates using either a Comb ilter for buzzes
Sonnox
Audio restoration software can be your greatest ally when it comes to
combating unwanted noise, but is this new package friend or foe?
System requirements
PC 1GB RAM, Windows XP/Vista 32,
VST/RTAS host, iLok
Mac 1GB RAM, OS X 10.4,
AU/VST/RTAS host, iLok
NOISE PROFILE
The frequency
curve of the noise
being dealt with
REMOVE
Controls how the noise
will be removed, and
by how much
AUDIO
Audition the audio with
the noise removed
DIFF
Lets you hear the
removed noise in isolation
DETECT
Settings for
the detection
of noise
Hear Restore at work in
our audio demos, and
read the manual
AUTO
In this mode, the
noise profile
constantly adapts
the background
noise in the signal
FREEZE
Great for capturing the profile
of isolated background noise
THRESHOLD BIAS
CURVE
This curve has a central
dip, giving less noise
reduction in the mids
100 / / June 2010
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