Waves Audio Z-Noise User Guide

Waves Z-Noise

Software Audio Processor

Users Guide

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1. Introduction

Waves Z-Noise is a single-ended broadband noise reduction audio processor. It

very effectively reduces noise while preserving the highest audio quality.
Superficially, Z-Noise works like other broadband noise reduction processors
which use a noise profile, or noise print, to differentiate valid signal from noise.
However, Z-Noise uses intelligent multi-level decision algorithms to maximize
noise reduction with minimum unwanted artifacts. Plus, Z-Noise uses a more
musical band spilt method for more natural results throughout the sound
spectrum.

Z-Noise is ideal for removing additive noise such as tape hiss, vinyl surface
damage, wind, air conditioner and ventilation system noise. Z-Noise offers
several improvements, including:

• Z-Noise works on the complete frequency spectrum, thus high-frequency
hiss and low-frequency rumble can be removed in the same pass. It is a
truly broadband noise removal tool.

• Real-time operation allows you to adjust parameters and hear the
results immediately.

There are several new features in Z-Noise which address problems unique to
broadband noise reduction:

• Extract Profile Mode – Not always do you have a section of pure noise from
which to create a noise profile. Using the Extract Noise Profile feature, you
can create a noise profile from a noise sample which is “contaminated” by
program material which you wish to save.

• Adaptive Mode - You do not necessarily need to create a noise profile in
order to reduce noise. In the Adaptive Mode, Z-Noise extracts a noise profile
on-the-fly and reduces the noise even if the profile changes over time.

• Better transient treatment –
well as enhanced transient processing options that allow for greater noise
reduction with less transients smearing.
transients prior to noise reduction processing, then de-enhance the transients
after noise reduction, thus allowing for more aggressive noise reduction while
preserving transients.

• Enhanced Noise profile adjustments – In both the normal and adaptive
modes, Z-Noise allows you to control the spectral nature of the noise profile.
In this manner you can more precisely define what is a noise and what is
program material. The noise profile can be equalized using a five-band
paragraphic EQ interface.

Z-Noise offers improved transient handling as

Z-Noise can detect and enhance

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• Knee control – Here you adjust the angle of the knee to smooth or sharpen
reduction dynamics.

How Does Z-Noise Work?

Z-Noise, like other broadband noise reduction algorithms, is essentially a multi­band expander that uses a noise profile to set the threshold within each band
according to the energy of noise analyzed in that band. When energy in a
specific band falls below the threshold, the input signal is presumed to be noise
or signal decaying into noise and the signal is attenuated in that frequency band.
Z-Noise employs the most recent psychoacoustic research and multilevel
decision algorithms to remove noise while preserving the sonic clarity of the
source. It performs much better than comparable DAW tools and as well as or
better than more expensive hardware solutions. Used wisely, Z-Noise reduces
noise while minimizing artifacts, and preserves the quality of the original
recording.

In the case of broadband noise reduction, noises are considered to be un­correlated from the musical signal. Z-Noise will do a great job of removing tape
flutter or analog hiss, for example, but it will not be able to reduce background
voices or anything that might be interpreted as signal, such as birds, crickets,
music, etc.

The Z-Noise is a single-ended noise reduction algorithm that does not require an
encoded original recording. Instead, it learns or extracts a noise profile from the
audio signal and uses this noise profile to help it to distinguish noise from audio
data.

Z-Noise’s controls are similar to those of a dynamics processor. Those familiar
with a typical compressor/expander should achieve excellent results within a few
minutes of experimentation.

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2. Using Z-Noise

De-noising with Z-Noise is a two-step process. First, you create a valid noise
profile, or signature, of the noise afflicting your audio. Then, use Z-Noise’s many
de-noising tools to obtain the perfect noise reduction to suit your program
material.

Step One – Create a Noise Profile

You must obtain a noise profile in order to effectively reduce noise. A noise
profile is the spectral density estimation of the noise, and is used by Z-Noise’s
noise suppression algorithms to make complex decisions as to what is a noise,
and should be eliminated, and what is not a noise, and should be left untouched.

Z-Noise provides five methods for creating a noise profile, depending the nature
of your original material and your desired work methods.

Default profile

When you start Z-Noise, a default white noise profile is loaded. This white noise
profile also loads when the Full Reset preset is chosen.

Factory presets

Other standard noise profiles may be loaded from factory presets.

Learn

Use the Learn mode when you have a clean sample of pure noise, with no
program material intruding upon the noise. Those familiar with Waves X-Noise
will be comfortable with this process.

Select a section of audio, at least 100ms long, which contains only the noise you
are trying to eliminate. Be careful to avoid “contaminations” from your source
audio, such as ring outs and false attacks.
Click the Learn button in the Noise Profile area below the Z-Noise analyzer. The

button will blink “Learning”
Noise. Click Learn again to stop the learning process and create the noise
profile, which appears as a white line on the Z-Noise analyzer. This line
represents the frequency content of the analyzed noise and changes its vertical
position as you modify the Threshold. At this point, save your Z-Noise setup,
which includes your noise profile. (For more on saving and recalling set-ups,
refer to the WaveSystem section at the end of this manual.)

If you cannot find a noise-only section, try using the default white noise profile or
one of the other available factory presets, or use the Extract Profile process
described below.

Extract

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. Play the selected audio section through Z-

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This option will enable you to create a fixed noise profile out of an audio section
where no “pure noise” is available, as you might encounter when cleaning music
on vinyl disks. To use this option, select an audio section in which the signal is
relatively quiet and whose program material “contamination” is representative of

the rest of program. Then click the Extract button. The button will blink
“Extracting.” Play the selection of audio. When finished, click the button again to
see the extracted noise profile.

Since Z-Noise will need to create an average calculation of the non-noise signal
in order to construct a valid noise profile, you should work with a relatively long
and representative sample when using the Extract Profile mode.
Remember, both the Learn and Extract methods are designed for recordings with
stable noise backgrounds. For modulating or changing background noises you
should choose the Adaptive method of creating noise profiles.

Adaptive

The Adaptive mode is used to eliminate noise that changes over time. Z-Noise
updates the noise profile by analyzing the input signal on-the-fly. Click the
Adaptive button, then play your DAW to sample the sound you want to clean. Z­Noise will start scanning the input audio and automatically assign a noise profile
(the initial noise profile will be a white noise profile or the last profile captured.)
The noise profile appears as a white line in the Analyzer window.

The Adaptive mode requires about two seconds of audio throughput before it
begins creating its own noise profile. During this initialization period, noise
reduction can be less than ideal, since Z-Noise lacks a valid noise profile. In
order to get optimal results from the beginning of your sound source, experiment
with these techniques:

1) Use the Learn mode to create a noise profile of a section of pure noise at

or near the beginning of your source audio. Z-Noise will begin Adaptive
mode noise reduction with this Learn mode noise profile, then migrate to
the Adaptive profile in a smooth way. This way you will have effective
noise reduction from the beginning of your source material, plus the
constantly updating noise reduction offered with the Adaptive mode.

2) If no pure noise is available at the beginning of your source audio, you can

use the Extract Profile mode to create a noise profile from a segment
containing both musical signal and noise. As in the previous example, this
noise profile will become the starting point in the Adaptive noise reduction
process.

3) If you don’t create a noise profile prior to starting an Adaptive mode noise

reduction process, Z-Noise will default to a white noise profile until it has
accurately created an Adaptive noise profile. After about two seconds, it
will shift to its new noise profile.

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