izotope rx 2 plug-in documentationhelp.izotope.com/docs/izotope-rx2-plug-in-help.pdf · keyboard...

iZotope RX 2 Plug-In

Documentation

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Table of Contents Introduction ............................................................................................................ 1

iZotope RX Plug-ins ............................................................................................... 1

Authorization ........................................................................................................ 2

Customer Support ................................................................................................. 3

Plug-Ins ................................................................................................................. 4

Standard Controls ................................................................................................. 4

Declip .................................................................................................................. 7

Declick ................................................................................................................ 9

Decrackle ........................................................................................................... 11

Remove Hum ...................................................................................................... 12

Denoise ............................................................................................................. 15

Spectral Repair ................................................................................................... 22

Working with Spectral Repair ................................................................................ 24

Workflow ......................................................................................................... 24

Editor ............................................................................................................. 25

Spectrogram Settings ....................................................................................... 30

Reference ............................................................................................................. 32

Options .............................................................................................................. 32

Keyboard Shortcuts ............................................................................................. 35

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Introduction iZotope RX Plug-ins

© 2001-2010 iZotope, Inc. All rights reserved. iZotope, iZotope.com, the iZotope logo, and RX are either registered trademarks or trademarks of iZotope, Inc. in the United States and/or other countries.

V 2.0.1.357

iZotope RX 2 Plug-In Documentation

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Authorization

Launching the Authorization Wizard

The first time you open RX, the Authorization Wizard will appear. You can choose to either authorize RX or use it in Trial mode for evaluation purposes. Please use your supplied RX serial number to fully authorize your product.

Trial vs. Demo Mode

For the first 10 days after installation, RX will run in Trial mode, which offers full functionality with the exception of saving and batch processing. After 10 days, RX will revert to Demo mode. In Demo mode, RX is limited to 30 seconds of continuous playback.

iLok Support

RX does support iLok. Our plug-ins will be able to detect iLok keys and assets if you already use iLok and PACE software on your system. If you don't already have PACE or iLok, we will not install any PACE or iLok software to your system, and iLok authorizations will be unavailable.

Help

We have created an online article to help with common questions about our authorization system.

Introduction

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Customer Support

How to purchase the full version of RX

If you are using the demo version of RX and would like the full version, you can purchase RX or RX Advanced direct from the iZotope online store.

http://www.izotope.com/products/audio/rx/

Once your purchase is complete you will be sent an email confirmation and a full version serial number that can be used to fully authorize your current installation of RX.

iZotope Customer Support Policy

iZotope is happy to provide professional technical support to all registered users absolutely free of charge. We also offer valuable pre-sales technical support to customers who may be interested in purchasing an iZotope product. Before contacting iZotope support, you can search our Product Knowledgebase to see if the solution to your problem has already been published.

http://www.izotope.com/support/center

How to contact iZotope for Technical Support

For additional help with RX, please check out the support pages on our web site at http://www.izotope.com/support or contact our customer support department at [email protected].

iZotope's highly trained support team is committed to responding to all requests within one (1) business day and frequently respond faster. Please try to explain your problem with as much detail and clarity as possible. This will ensure our ability to solve your problem accurately, the first time around. Please include all system specs and the build/version of RX that you are using.

Once your support request is submitted, you should automatically receive a confirmation email from iZotope support. If you do not receive this email within a few minutes please check your spam folder and make sure our responses are not getting blocked. To prevent this from happening please add [email protected] to your list of allowed email addresses. Thanks for using RX!

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Plug-Ins Standard Controls

RX plug-ins share several common controls.

Presets:

From the Presets drop down menu, you can select from default presets and presets you have saved.

Add - Clicking this button adds the current RX settings as a new preset. You can type a name and optionally add comments for the preset. Note that a few keys such as * or / cannot be used as preset names. If you try to type these characters in the name they will be ignored.

Note: This is because presets are stored as xml files (for easy backup and transferring). Their file names are the same as the name you give the preset (for easy reference) and therefore characters that are not allowed in Windows file names are not allowed in preset names.

Remove - To permanently delete a preset, select the preset from the list and click the Remove button.

Update - When you click the Update button your current settings are assigned to the selected preset (highlighted). This is useful of course for selecting a preset, tweaking it, then coming back to the preset system and clicking Update to save your changes to the existing preset.

Cancel - The Cancel button simply closes the preset system dialog and reverts the settings back to the previous Current Settings, which would be either the settings when you entered the preset system or the settings of the last preset you created or updated while the preset system was open.

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Note: You cannot "Cancel" an update of a preset. That is, adding, removing, and updating presets are done "in place" and are not reverted when you Cancel the preset system dialog.

OK- Closes the preset system, but unlike the Cancel button, clicking the OK button loads the last preset you selected from the preset list.

Renaming Presets - You can double click on the name of a preset to enter the "edit" mode and then type a new name for that preset.

Change Folder - click the Change Folder button and browse to the folder that contains the presets you want to use.

More Presets - If you're connected to the internet, clicking this button will take you a page on iZotope's site that contains additional user submitted presets.

Your presets are located at the directories below:

Windows Users

C:\Documents and Settings\<your username>\My Documents\iZotope RX 2 Presets

Mac Users

<username>\Documents\iZotope RX 2 Presets

History:

Selecting the History button opens the History window. This view gives you a list of all of the actions you've performed inside the plug-in, allowing you to step back to previous settings and undo changes.

Compare Buttons - The buttons marked A, B, C and D can be linked to different steps in the history list (using the Set buttons. This allows you to compare different settings by switching back and forth between the compare buttons.

Clear - Resets the History list.

Input/Output:


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Each plug-in features an input and output gain control and input and output metering.

Link - the link buttons below the input and output faders allow you to unlink the left and right controls. When the switch is engaged, the left and right faders will move together, when disengaged they will move independently.

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Declip

Declipper repairs digital and analog clipping artifacts that result when A/D converters are pushed too hard or magnetic tape is over-saturated. Declipper can be extremely useful for saving recordings that were made in a single pass, such as live concerts or interviews, and any audio that cannot be re-recorded.

The histogram meter in the Declipper module allows you to set the Clipping Threshold control by finding the audio level where the waveform's peaks are concentrated. This usually indicates at what level clipping is present in the file.

Using the Histogram to set the Clipping Threshold

Select a section of the recording where clipping is prominent, then click the Compute button. This will analyze the levels of the program material. If clipping is present in the selection, it will usually appear as a horizontal line in the histogram that extends all the way across the meter.

To set the module's threshold, move the red line in the histogram, or the Clipping Threshold slider, until the red line in the histogram is just below the line where clipping is concentrated.

Adjusting the Clipping Threshold will display a red line within the histogram and the waveform itself. This red line shows the level on the waveform above which the declipper algorithm will process the audio file. All sections of the waveform above this level will be regarded as clipping. Within the histogram itself the elements of the file that will be processed (above the red line) will appear white.


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Declipper repairs digital and analog clipping artifacts that result when A/D converters are pushed too hard or magnetic tape is over-saturated. Declipper can be extremely useful for saving recordings that were made in a single pass, such as live concerts or interviews, and any audio that cannot be re-recorded.

Note: if the clipping point is below -8 dB FS, the histogram will be empty. Your file may need to be normalized. You can also raise the overall gain of the file using RX's Gain module.

The histogram meter in the Declipper module allows you to set the Clipping Threshold control by finding the audio level where the waveform's peaks are concentrated. This usually indicates at what level clipping is present in the file.

Using the Histogram to set the Clipping Threshold

As you play a selection of your recording with Declipper active, the histogram will analyze the levels of the program material. If clipping is present in the selection, it will usually appear as a horizontal line in the histogram that extends all the way across the meter.

To set the module's threshold, move the red line in the histogram, or the Clipping Threshold slider, until the red line is below the line where clipping is concentrated.

Start by setting make-up gain at around -6.0 dB. This control accommodates the increased peak levels caused by the declipping process. If you're removing clipping during a short selection of a file, you may want to set this control higher to prevent a noticeable volume drop in the program material during the declipped section.

Makeup Gain

There are three quality modes in RX's Declipper: Low, Medium, and High. Low quality mode processes very quickly; High quality mode processes slowly but in some cases can achieve better results. In many cases you will find that "Low" quality mode gives you great results.

Choosing a quality mode

Depending on the power of your computer, you may only be able to use the higher quality modes offline (when you bounce down or apply effects to a track or file). If this is the case, try using Low quality mode to preview in realtime, then when rendering use a higher quality mode.

Declip Controls:

· Quality

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- controls the interpolation processing quality.

Clipping threshold (dB FS)

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- selects the clipping level used for detection of clipped intervals. User should set it to be just below the actual level of clipping.

Makeup gain (dB)

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- selects the gain to be applied to the selection after declipping.

Histogram

Clipping Threshold Resolution - The Clipping Threshold’s range can be scaled to fit your audio application. Use the (+) and (-) buttons to scale your display and value resolution for your declipper module. These buttons reduce (+) and/or expand (-) the range of the threshold slider and histogram. You may want to extend the histogram range when your clipping point is lower than what you can see on a histogram.

- a graphical display of waveform levels over time.

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Declick

When to use Declicker

Declicker is useful for restoring for old vinyl and other phonograph recordings that are riddled with clicks, pops and crackles. Declicker can also remove a variety of short impulse noises from other sources, including some clicks caused by digital errors.

If your host has a spectrogram display, it is a good idea to visually identify clicks to inspect how wide they are, as this will help you see roughly what your Algorithm and Strength should be set to.

Using Declicker

As audio is playing back, fine tune the strength slider to remove the most clicks and pops. The ideal setting should remove the most clicks without damaging transients in the program material. For example, drum hits may be mistaken for clicks at high Width and Sensitivity settings.

To better hear what is being removed, toggle the Output Clicks Only control during playback. This will let you hear what is being removed from the audio, allowing you to fine tune your settings.

Note: for material with clicks and pops of very different sizes, try running Declicker in several passes. Start with repairing short clicks, and then continue to longer ones.

· Algorithm - controls the interpolation processing quality and configuration depending on the type of clicks and pops in the audio.

Declicker Controls:

· Single-Band - Processes quickly and works well on very narrow "digital" clicks


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· Multiband (random clicks) - Works well with wider vinyl clicks and thumps and has a protective algorithm for preserving periodic audio elements characteristic to certain instruments such as Brass or Vocals.

· Multiband (periodic clicks) - Most suitable for removing periodic clicks with a wider spectrum

· Strength- controls the amount of clicks that are detected and repaired. Low values of this parameter will remove fewer clicks, while higher values can repair too many intervals which can result in distortion.

· Output clicks only - outputs the difference between the original and processed signals (suppressed clicks)

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Decrackle

Decrackle

Typically, the duration of a single click and pop will not go beyond 10 ms. Decrackler is designed to handle a more continuous stream of irregularities in your audio that become blended together at lower amplitude levels, resulting in what we hear as crackle.

TIP: Decrackle is not designed to be used instead of Declick. On the contrary, the best results can be had by first running the Declick module, and afterward, processing with Decrackle.

· Quality - controls the interpolation processing quality

Controls:

· Strength- controls the amount of crackle that is detected and repaired.

· Amplitude bias - Allows for greater or lesser processing to be applied to higher or lower amplitude signals. Values above 0 dB will apply more processing to high-amplitude signals vs. lower amplitude signals. This can be an effective tool at removing traces of clipping that may not be repairable by the Declip module.

· Output crackle only - outputs the difference between the original and processed signals (suppressed clicks)


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Remove Hum

When to use Hum Removal

Hum removal is designed to remove low frequency hum from your audio. Hum is often caused by lack of proper electrical ground. This tool includes a series of notch filters that can be set to remove both the base frequency of the hum (usually 50 or 60 Hz) as well as harmonics that may have resulted.

NOTE: the RX Hum Removal plug-in is effective for removing hum that has up to seven harmonics above its primary frequency. For hum that has many harmonics that extend into

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higher frequencies (often described as "buzz"), try using RX's Denoiser plug-in. For tricky hum and buzz problems the Denoiser features "Tonal Noise" suppresion controls under its Advanced tab.

To begin, select a section of the recording where the hum is prominent. Sometimes there will be silence (or near silence) at the beginning or end of the program material that will contain noise but not any other audio. Otherwise, try choosing a quiet passage of the recording where hum is obvious.

Previewing the Hum

Next, set a loop points in your host program around a section of audio where the hum is most clearly audible. This will allow you to set Hum Removal's parameters as audio plays back.

Finding the Hum's frequency

When attempting to remove hum, you first need to find the hum's primary frequency. The two most common base frequencies that cause hum are 50 Hz (Europe) and 60 Hz (U.S.). Under the Frequency Type field in the Hum Removal module, choose the appropriate frequency and listen to hear if this has an effect.

In some cases, for example a recording made from analog tape that is not precisely at its original recorded speed, you may need to choose the "Free" Frequency Type. Selecting this option unlocks the Base Frequency control and allows you to manually find the Hum's root note. With audio playing back, move the slider up and down until you find the point where the hum lessens or disappears.

Learn

The Remove hum module can also automatically locate the root fundamental of any hum in your audio. Simply make a selection containing the trouble frequencies, and click the "Learn" button. This will automatically change the mode to "Free" and set the Base Frequency to the result of the "Learn" calculation. If the hum continues throughout the entire audio file, clicking on "Learn" without previously selecting any audio, RX will analyze the entire audio file in order the find the Base Frequency of the Hum.

Because higher frequency harmonics often result from hum, RX's Hum Removal module has control for attenuating these overtones. Using the Number of Harmonics control, you can select up to 7 harmonics above the primary hum frequency. Again, the spectrogram display in many cases makes it easy to identify the number of hum harmonics in your project. After selecting number of harmonics, use the Harmonic Slope control to how aggressively the higher harmonics are being cut. The Filter Q control adjusts the width of the hum filters.

Attenuating Hum's Harmonics

By selecting the Output hum only checkbox, you can also hear only the hum that is being removed. This is useful for fine tuning your settings. Play through a section of your file where the hum is mixed with other material, and select Output hum only mode and then hit Preview.

Using Output Hum Only

Now you can adjust parameters like the Filter Q (width) control and the Harmonic Slope control to maximize hum removal while minimizing the affect on the program material.

Hum Removal Controls:


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· Residual output

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- outputs the difference between the original and processed signals (suppressed hum)

Frequency Type

· Learn - analyzes the current audio selection in order to automatically locate and set the base hum frequency.

- sets the base frequency of the hum to be removed. The two most common base frequencies that cause hum are 50 Hz (Europe) and 60 Hz (U.S.). Other base frequencies can be selected by choosing the 'Free' option.

· Linear-phase filters -

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enables linear phase filtering mode

Base frequency (Hz)- this slider is only enabled when the Frequency Type is set to

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Free

Filter Q

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- controls the bandwidth of filters for base frequency and harmonics

Enable highpass filter -

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allows high frequencies to pass while attenuating lower frequencies.

Highpass frequency(Hz)

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- sets the cutoff frequency for the filter

Highpass Q

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- sets the bandwidth of the highpass filter

Enable lowpass filter -

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allows low frequencies to pass while attenuating high frequencies.

Lowpass frequency(Hz)

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- sets the cutoff frequency for the filter

Lowpass Q

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- sets the bandwidth of the lowpass filter

Num Harmonics -

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select the number of harmonics that need to be removed (1-8)

Linking Type -

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here you can choose to link the gain/suppression of all of the filters, none of the filters, or odd/even filters

Harmonic slope

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- when harmonics are linked, this controls the slope of the gain/suppresion. As the harmonic order increases the gain/suppresion level resolves closer to 0 dB.

Harmonic even/odd slope

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- when linking type is odd/even, this allows you to control the amount of gain/suppression for both odd and even harmonics

Filter DC Offset -

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this removes the DC (direct current) offset that is caused by the imbalance that sometimes occurs in A/D converters. DC offset is exhibited by the waveform appearing above or below 0 dB.

Harmonic gains (dB): gives numerical readout of gain settings in dB. You can also manually type in your gain settings for any of the harmonics.

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Denoise

Denoise is designed to reduce stationary noise, including broadband noise, in audio signals. Stationary noise can include tape hiss, microphone hum, power mains buzz, camera noise and other types of noise that do not change in level or spectral shape throughout the recording.

Denoise can learn the type of noise you want to remove from the recording to give you the best results. To train Denoise, identify a section of the recording that contains only noise, without any useful audio signal. Often these places are at the beginning or end of a file, but may also be during pauses or breaks in speech.

Training Denoise

Select the longest section of noise you can find. Using the tools in your host program, you may want to loop a selection of noise-only signal and let it play. Hit the Learn button as the noise plays back, then click the button again to finish capturing the noise. This will "teach" Denoise the noise profile of your file. In some cases you may not have a section of just noise, in this case try to find the quietest section possible to train the Denoise.


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As audio is playing back, adjust the Noise Reduction slider and Smoothing controls until you get the result you want.

Denoising

Note: the B and C Algorithms are quite processor-intensive, so you may wish to preview noise reduction in the A (realtime) mode, and then switch Algorithms when bouncing down or rendering the effect.

It is usually a good idea to find a balance between a lot of noise being removed, and maintaining the natural sound of the original source material. Using the Output Noise Only checkbox allows you to preview just the noise that is being removed. If when this box is checked you hear audio you want to keep being removed, you may want to set the Noise reduction controls less aggressively.

Output Noise Only

If you are using the Simple panel, you can adjust the desired amount of Noise suppression. If you are using Advanced panel, you can separately adjust amount of noise reduction for tonal and broadband parts of noise, and fine tune the noise reduction process with some additional parameters. To read more about Advanced parameters see the Control Reference section below.

The Smoothing (Simple tab) and Global and Fine Smoothing (Advanced tab) controls suppress artifacts that result from removing broadband noise.

Smoothing

Fine Smoothing controls the reduction of these artifacts which can be a result of heavy denoising. Musical noise is caused by random statistical variations of noise spectrum that cause random triggering of sub-band gates. These artifacts are sometimes described as "chirpy" or "watery" sounds left behind during the noise reduction process.

Global Smoothing determines how much noise reduction will depend upon wide band gating or spectral subtraction. With higher values, the noise reduction will rely more heavily upon wider band gating which can produce less artifacts than a spectral noise reduction.

With lower values, noise reduction will rely upon spectral subtractions which can more accurately separate noise from the desired audio signal.

Choosing an Algorithm

RX's Denoise module offers four algorithms that range in processing time.

· Algorithm A is the least cpu intensive process and is suitable for realtime operation. It reduces musical noise artifacts by time smoothing of the signal spectrum.

· Algorithm B has more advanced musical noise suppression by using adaptive 2D smoothing (both time and frequency). It is more cpu intensive and has more latency, but can still run in realtime on most machines.

· Algorithm C adds multi-resolution operation for better handling of signal transients and even less musical noise artifacts. It is a very cpu intensive algorithms and can only run in realtime on fastest multi-core machines.

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· Algorithm D (new to RX 2) adds global smoothing of musical noise and high-frequency synthesis for reconstruction of signal details buried in noise. The speed of algorithm D is similar to the algorithm C.

In general, it is a good idea to start with Algorithm A, as it works very quickly. If you're not happy with the result, try B and then C or D, which will take longer to process but can yield better results. Algorithms B, C and D are fairly slow, and may not be able to preview in realtime.

Noise Spectrum Display:

The Noise Spectrum display shows useful information during both playback and when the noise reduction process is being applied.

Color Legend

· Purple curve (Input) - spectrum of input audio signal

· Yellow curve (Output) - spectrum of denoised (output) audio signal

· Blue curve (Noise Profile) - equals learned noise profile + threshold elevation control

· White curve (Residual Noise) - desired noise floor after denoising, can be controlled by Reduction and Residual whitening controls (Advanced mode only)

Scrolling and Zooming - by grabbing and moving the horizontal and vertical rulers, you can adjust what part of the graph is shown. In addition, holding the pointer above a ruler and using your mouse wheel will zoom the display in and out.

Simple Mode Controls:

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Algorithm

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- affects the quality and computational complexity of the noise reduction. This selection directly affects CPU usage.

Noise Reduction (dB)

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- controls the desired amount of noise suppression in decibels.

Artifact Suppression

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- helps minimize "musical noise" artifacts introduced during the noise reduction process.

Residual output

- outputs the difference between the original and processed signals (suppressed noise)


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Advanced Mode controls:

Threshold (tonal/broadband)

Higher threshold settings reduce more noise, but also suppress low-level signal components. Lower threshold preserves low-level signal details, but can result in noise being modulated by the signal. Threshold elevation can be done separately for tonal and random noise parts. A good default is 0 dB.

- controls the separation of noise and useful signal levels.

Reduction (tonal/broadband)

Denoise can automatically separate noise into tonal parts (such as hum, buzz or interference) and random parts (such as hiss). The user can specify the amount of suppression for these parts separately (e.g. in some situations it can be desirable to reduce only unpleasant buzz while leaving unobjectionable constant hiss). Strong suppression of noise can also degrade low-levels signals, so it's recommended to apply only as much suppression as needed for reducing the noise to levels where it becomes less objectionable.

- controls the desired amount of noise suppression in decibels.

Artifact Control

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Global Smoothing - Determines how much noise reduction will depend upon wide band gating or spectral subtraction.

With higher values, the noise reduction will rely more heavily upon wider band gating which can produce less artifacts than a spectral noise reduction.

With low values, noise reduction will rely upon spectral subtractions which can more accurately separate noise from the desired audio signal.

Fine Smoothing - controls the reduction of artifacts known as "musical noise" that can result from heavy denoising. Musical noise is caused by random statistical variations of noise spectrum that cause random triggering of sub-band gates.

TIP: Bring this to a low value where artifacts become apparent and then raise the control just to the point where artifacts disappear.

More Advanced Mode Controls: (Advanced Only)

A

This option will allow Denoise to alter its noise profile based on the incoming changing noisy audio. The specified learning time will allow RX to analyze incoming audio, decide what is noise and what is desired audio material, and adjust its noise profile accordingly. An incredibly powerful feature, adapting noise profiles can work well with noise sources that are constantly evolving particularly in post-production film settings or outdoor environments.

dapt to changing noise profiles

MNS algorithm

The strength of smoothing is controlled by the "Musical noise suppr." slider.

- selects the smoothing algorithm for the removal of random ripples that can occur in the spectrogram when processing your audio. These sounds are referred to as "musical noise" and can be described as sounding "watery".

· Simple algorithm performs independent noise gating in every frequency channel of FFT. Release time of sub-band gates is controlled by the Release control. This is a fast algorithm with small latency that is suitable for real-time operation.


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· Advanced and Extreme algorithms perform joint time-frequency analysis of the audio signal which results in better quality and less "musical noise" artifacts. These algorithms have higher latency and computational complexity.

FFT size (ms)

Note: Whenever FFT size is changed, it's recommended that the user retrain the Denoise's noise profile because the old noise profile was taken at a different FFT size and therefore becomes inaccurate.

- selects the time and frequency resolution of the processing. Higher FFT sizes give you more frequency bands allowing you to cut noise between closely spaced signal harmonics, or cut steady-state noise harmonics without affecting adjacent signals. Lower FFT sizes allow for faster response to changes in the signal and produces less noisy echoes around transient events in the signal.

Release (ms)

Longer release times can result in less musical noise, but may also reduce or soften the signals initial transients or reverb tails after the signals decay.

- selects the release time of sub-band noise gates in milliseconds

Note: The Release control is only available when the 'Simple' MNS Algorithm is selected.

Multi-resolution

When you select the "Multi-resolution" checkbox, the signal is analyzed in real time and the most appropriate FFT size is chosen for each segment of the signal. This is done to minimize the smearing of transients and at the same time achieve high frequency resolution where it is needed.

- enables multi-resolution for the selected algorithm type

Note: The FFT size control does not have any affect in multi-resolution mode as the FFT resolution is selected automatically. The noise profile does not need to be re-learned when switching to Multi-resolution mode.

Residual Whitening

When residual whitening is zero, the suppression is uniform at all frequencies, as controlled by Reduction (tonal/broadband) sliders, and the suppressed noise has a similar spectral shape to the original noise. When residual whitening is maximal, the desired shape of suppressed noise floor is made close to white, so that residual noise has more neutral sound.

- modifies the amount of noise reduction (shown by light blue curve) applied at different frequencies to shape the spectrum of the residual noise.

Harmonic enhancement

HF Synthesis - improves upon any dullness as a result of Denoise processing by resynthesizing high frequency signal content. A higher value will give the maximum amount of resynthesis while 0.0 will turn this feature off.

- predicts a signals harmonic structure and places less noise reduction in areas where possible signal harmonics could be buried in noise. This aids in at least preserving high-frequency signal harmonics that may be buried and not detected otherwise. It can make the resulting signal brighter and more natural sounding, but high values of harmonic enhancement can also result in high-frequency noise being modulated by the signal.

Knee sharpness

This slider controls the bending "knee" softness in the denoising process. With higher values, transitions in the denoise are more abrupt and can become prone to errors in the detection of the signal with respect to the noise. When the sharpness is reduced, the denoising becomes more forgiving around the knee, and applies less attenuation to signals

- controls how surgical the algorithm's differentiation is between the signal and noise.

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that are only slightly below the threshold. This may result in a lower depth of noise reduction, but can also have fewer artifacts.

Suppression Masking - enables a psychoacoustic model that dynamically controls suppression amount to facilitate the use of softer suppression where noise is subjectively inaudible. When noise in certain regions is calculated to be inaudible, this feature prevents any signal processing in these regions. This potentially reduces amount of processing done to the signal and may positively affect overall signal integrity. The position of the slider controls the influence of psychoacoustic model on suppression levels.

Note:When this slider is set to 0, the feature is turned off, and the amount of noise suppression is uniformly governed to the white curve in spectrum analyzer (more precisely - by the difference between the white curve and blue curve).

Additional Denoise Features:

· Noise Suppression Envelope - This feature allows for fine tuning of the noise suppression envelope with up to 26 edit points. This enables the user to customize the amount of noise reduction being applied across different frequency regions.

· Add an edit point - Left-click, displayed as gray box along envelope curve

· Remove an edit point - Right-click (CTRL click on Mac) or drag it outside the screen

· Envelope Show - This controls whether or not the suppression envelope points are visible or hidden. The modified envelope will always be applied even when edit points are hidden.

· Envelope Reset - This will remove all edit points.

· Envelope Smoothing - This controls the amount of interpolation between your suppression envelope points, allowing for sharper or more gradual envelopes.


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Spectral Repair

Spectral Repair is a tool for interpolating selected areas on a time-frequency spectrogram. It is able to provide higher quality than the Declicker tool for long corrupted segments of audio (above 10 ms).

Spectral repair can be used to remove (or attenuate) certain unwanted sounds from recordings, such as squeaky chairs, coughs, dropped objects, mobile phones ringing, etc. It can also close up gaps in audio by using advanced resynthesis techniques.

The plug-in version of Spectral Repair is an offline tool only, by its nature it cannot be used as a track insert or bus plug in. You must follow a 3 step process, starting by capturing audio from your host, then processing it within the Editor window, then committing the changes back to your host.

Processing Limitations

Depending on the mode and settings, Spectral Repair will have varying limits to the amount of audio that can be processed in your selection.

· Unlimited - Attenuate when in Vertical mode

· 10 seconds - Attenuate Horizontal or 2D, Replace modes;

· 4 seconds - Pattern, Partials+Noise modes.

Note: Spectral Repair cannot process selections longer than 4 seconds. For simpler operation we recommend you try using the iZotope RX standalone application (included with these plug-ins) for Spectral Repair. The specific nature of this type of repair simply lends itself better to a dedicated host.

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Spectral Repair has several tabs representing different modes of interpolation.

Understanding Spectral Repair Modes

· Attenuate mode

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is suitable for recordings with background noise or where noise is the essential part of music (drums, percussion) and should be accurately preserved. It's also good when unwanted events are not obscuring the desired signal completely. For example, this mode can be used to bring noises like door slams or chair squeaks down to a level where they are inaudible and blend into background noise.

Replace mode

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can be used to replace badly damaged sections (such as gaps) in tonal audio.

Pattern mode

·

is suitable for badly damaged audio with background noise or for audio with repeating parts. It searches surrounding areas for a similar piece of audio and blends it into the selection.

Partials+Noise mode is the advanced version of Replace mode. It restores harmonics of the audio more accurately with control over the Harmonic sensitivity parameter. This mode links detected harmonics by synthesizing them through the selection, and interpolates the rest of the signal using the Replace method.

·

Spectral Repair Controls

Number of bands

·

- selects the number of frequency bands used for interpolation. A higher number of bands can provide better frequency resolution, but also requires wider surrounding area to be analyzed for interpolation.

Strength

·

- parameter adjusts strength of attenuation in Attenuate mode.

Surrounding region length

·

- defines how much of the surrounding content will be used for interpolation

Before/after weighting

·

- gives more weight to the surrounding audio before or after the selection

Harmonics sensitivity

· Pattern Search Range - in Spectral Repair Pattern mode, selects the length of the audio segment used in a search for a suitable replacement interval. For example, setting it to 5 seconds will allow search within +/-5 second range from the selection.

- adjusts amount of detected and linked harmonics in Partials + Noise mode. Lower values will detect fewer harmonics, while higher values will detect more harmonics and can introduce some unnatural pitch modulations in the interpolated result.

Multi-Resolution

The Multi-resolution mode enables multi-resolution mode when better frequency resolution is used for interpolation of low-frequency content and better time resolution is used for interpolation of high-frequency content. The Multi-Resolution processing options is available for each of the Spectral Repair modes individually.


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Working with Spectral Repair

Workflow

Welcome to the iZotope Spectral Repair plug-in. Please note that Spectral Repair is very different from most other audio plug-ins. It first needs to Capture audio from the host, then you can Repair the audio, and finally you must Commit your edits back to the host.

For Spectral Repair to work, it requires a host which supports offline processing. If yours does not, we recommend that you use Spectral Repair in the iZotope RX application which was installed when you installed the RX plug-ins.

Capture

From Sequencer view, select up to 10 seconds of audio to be captured by Spectral Repair.

Open the offline version of Spectral Repair via the menu "Audio > Audio Plug-ins > iZotope RX Spectral Repair.

Click the "Capture" button at the bottom of the Spectral Repair window.

Press the Digital Performer plug-in "Apply" button. The Spectral Repair window will close.

Reopen Spectral Repair and click the "Editor" button at the bottom of the Spectral Repair window.

Repair

Now you can use the Spectral Repair Editor window to repair your audio. Please click the "?" button in the upper-right corner of this window for more details about repairing your audio. You can click Digital Performer's "Preview" button to preview your edits.

Commit

Press the Digital Performer plug-in "Apply" button.

Note: If you capture audio using Digital Performer's "Preview" button, it will introduce silence at the beginning and the end of the selection and you won't be able to properly apply processing. This is why we recommend that you use the above method for perfect edits with Spectral Repair.

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Editor

Clicking the "Editor" button in the Spectral Repair plug-in will open the Editor window. The editor window allows you to analyze a captured piece of audio with the spectrogram then select by time and/or frequency to apply Spectral Repair processes.

The spectrogram and waveform display window combines an advanced spectrogram with a transparency feature to allow you to view both the frequency content and amplitude of a file simultaneously.

Overview

Transparency

The transparency of the waveform and spectrogram can be adjusted with the transparency slider to the lower left of the display.

Repair

After choosing a Spectral Repair mode and settings in the main plug-in window, click process to apply Spectral Repair to the selected region.

The arrow buttons below the Spectrogram Display allow you to undo or redo edits made in the editor window.

Undo/Redo

Zoom


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To the lower right of the display, you will find horizontal and vertical sliders. The horizontal slider will affect how much of the time ruler is represented on the screen. The vertical slider controls the frequency range shown in the spectrogram.

You can also zoom by clicking on a ruler and moving your mouse wheel.

Selection Tools Below the Spectrogram display is a Selection Tools menu that gives you several options.

One of the key benefits of RX is that it allows many options for selecting audio not just by time, but also by frequency. This allows you to do work with sounds that fall in only part of the frequency range at a given point in your project. This is very helpful for isolating and repairing a variety of audio problems including intermittent background noises.

Above image shows election by time and frequency isolating a background noise for processing

The Time Selection tool allows you to select a segment of your project along the time line.

The Time-Frequency Selection tool allows you to make rectangular selections in the Spectrogram Display to isolate sounds by time and frequency.

The Frequency Selection tool lets you select by just frequency (vertically in the Spectrogram)

The Lasso Selection tool lets you use your mouse to outline any selection you wish in time and frequency in RX's Spectrogram

The Brush Selection tool lets you draw any selection you wish using a defined brush size in time and frequency in RX's Spectrogram.

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The Brush Size can be adjusted by clicking and holding on the Brush Tool icon.

Note: With the brush tool selected, you can also hold CTRL/Command and move the mouse wheel to make the brush size larger or smaller.

The Magic Wand Selection tool

· Single Click - The Magic Wand tool will automatically select the desired harmonic

will cause RX to automatically select similar harmonic content surrounding the selected material

· Double Click - The Magic Want tool will automatically select the desired harmonic, as well as all overtone harmonics or related audio components.

The Zoom Selection tool, when enabled, zooms into time and frequency selections as you make them.

The Grab and Drag tool allows you to move around your view of the spectrogram when zoomed in

Keyboard Modifiers (PC/Mac)

.

Shift

Hold down shift after making one selection in order to add another separate selection. If any part of the new selection overlaps any other, the selections will be grouped into one.

This can be especially powerful when combining multiple selection tools to create multiple selections of different size and shape.

Alt/Option


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Holding down Alt/Option will allow you use the currently chosen selection tool to remove or erase any portion of an existing audio selection. This can be especially useful with the "Lasso" or "Brush" tools, allowing you to edit or refine any piece of an existing selection.

Control/Command

Hold down Control/Command to move the transport's playhead to any position without erasing your current audio selections. This can be especially useful with previewing or comparing complex audio selections without having to remake these specific audio selections.

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Note: Using Control/Command - Z to undo any particular process will also bring back the previous audio selection exactly as it was before applying any processing. In order to make use of this feature, be sure that the "Store Selections with Undo History" option is turned ON inside of RX's "Preferences -> Misc." menu.

Mouse Over

After using any of RX's tools to select a portion of your audio, when the mouse is subsequently placed on top of any selection, a Grab and Drag hand cursor will be displayed automatically, allowing you to change the position of that selection.

Channel Selection When working with a stereo file, it can be necessary to only process the left or right channel of your audio file. To do so, simply make the selection that you wish to process, and click on either of the channel selectors to the left of the spectrogram/waveform main display. This can also be used during playback in order to preview either the left or right channel.


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Spectrogram Settings

Our spectrogram has been designed to provide more sharpness and detail than other spectrograms. The Spectrogram Settings menu allows you to adjust advanced settings like FFT size (frequency resolution), window and colors. Try starting with the provided presets to see how the settings affect the display.

Spectrogram Settings:

·

Type -

·

select the type of spectrogram calculation algorithm

Enable reassignment -

·

enables reassignment technique for spectrogram sharpening, use together with time and frequency overlap controls

FFT size -

·

sets FFT size for spectrogram calculation in samples

Window -

·

sets FFT weighting window, which addresses frequency smearing

Frequency overlap -

·

sets FFT zero padding, which enhances frequency resolution

Time overlap -

·

sets overlap of FFT windows, which enhances time resolution

Frequency scale -

·

sets frequency scale type for spectrogram display

Color map -

·

allows for different color choices in spectrogram color map

Show spectrogram color map -

·

this will display the spectrogram color map bar

High quality rendering -

·

accurate max-bilinear interpolation of a spectrogram (recommended)

Amplitude range (low) -

·

sets spectrogram amplitude range, lower bound (dB)

Amplitude range (high) - sets spectrogram amplitude range, upper bound (dB)

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· Reduce quality above (seconds) -

·

this reduces the spectrogram calculation quality when its size is above a specified amount of seconds

Cache size (MB) - Limits the amount of memory used by the spectrogram

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Reference Options

General

This group of options allows you to enable or disable meters and animation effects. Disabling these options saves system resources for better performance on slower computers.

Graphics:

·

Performance:

Delay Compensation

·

- Some of the processing modes in the RX plug-ins are very CPU intensive and result in a delay of the signal. That is, RX needs some time to "work on" the audio before it can send it back to the host application. That time represents a delay when listening or mixing down. Fortunately, many applications provide "delay compensation" - a means for RX to tell the application it has delayed the signal, and the host application should "undo" the delay on the track. If your host application supports delay compensation, select this option. If your application doesn't support it, or skips/stutters with this option on, you can always manually correct the delay offset in the host application (i.e. manually edit out the short delay of silence). To help you perform manual correction, the delay RX introduces is shown below "Total System Delay" in both samples and milliseconds.

View Buffers

·

- Shows buffer information from the host's track.

Host Sync - Shows information reported from the host program about playback location, tempo, etc. (when applicable).

The maximum number of steps (undo points) the plug-in will save in its history list.

History Depth:

I/O (Input/Output Meters)

Reference

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Metering:

·

This is a combined RMS and Peak meter. This meter displays a lower bar representing the average level (RMS) and a higher bar representing peak level. There is also a moving line above the bar representing the most recent peak level or peak hold.

Enable I/O meters

·

- Turns on or off the level meters

Show peak hold

·

- Turns on or off the peak hold display for the level meters

Peak hold time

·

- If peak hold is on, clicking this button allows you to cycle through different peak hold times. The choices are 250 msec, 500 msec, 1000 msec, 5000 msec and infinite. If set to infinite, the peak value will be held until you double click on the meter.

Integration time

·

- This setting only applies if the level meter is set to RMS. It lets you specify the integration time for the RMS calculation. In most RMS meters, the integration time is set to around 300 msec.

Readout - Allows you to control what is displayed by the numeric display on top of the meters: peak or actual (real time). If set to Max Peak, the display will reflect the meter's current value. If there are two levels displayed (Peak+RMS) we read the RMS value.

Authorization

Use the authorization menu to remove your current RX authorization, for example if you have upgraded to RX Advanced and have already installed the basic version. You may also


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need to de-authorize RX if you are using the RX trial version and wish to try the RX Advanced trial version.

After removing your authorization, RX's authorization screen will pop up when you restart the program. Now you can re-authorize the application using your new serial number.

Updates

RX can check the iZotope download servers for program updates by clicking on the 'Check Now' button or automatically upon launch of the application.

Denoise Plug-in Options:

Max processors to use for Algorithm C - If your computer has one or more processor or processing core, you can set RX to process Denoiser Algorithm C more efficiently. Setting a higher number spreads the processing out over multiple cores/processors.

Reference

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Keyboard Shortcuts

Keystroke

Tab

(Windows/Mac)

Move the control focus to the next control

ENTER Toggle buttons and check boxes On or Off, select items from lists

Left/Right Arrow Increase and decrease value of control

Up/Down Arrow Navigate Up and Down in menus

Page Up/Down Move controls by a large amount

CTRL/Command Hold while adjusting parameters to move controls by a smaller increment for greater precision

Mouse Wheel Used to increase or decrease the value of a control. Can also be used with CTRL for more precision