WAVE EDITOR / RECORDER
Noise Removal Tool
The Noise Removal Tool is built on iZotope RX technology and can independently
remove background noise (tonal or broadband) from a sample, repair clipped samples and remove clicks from samples. Any or all these denoise functions can be performed in a single pass. The modules are
activated by the button in front of each section label.
NOTE: The Denoiser, Declipper and Declicker have a button preceding the section titles, this activates the given function when selected. The Declipper and Declicker are deactivated in the screenshot above.
To Open the Noise Removal Tool
To open the Noise Removal Tool Left-click on the Clean up (denoise) button or use the
Tools > Spectral > Clean up (denoise) option.
Residual vs Removed Sound
Above the main display window.
- Output noise only - When selected the parts of the sample removed by the Denoiser tool (noise) are heard. Select this button when you need to fine-tune the Denoiser process Threshold and
Amount settings (using the Preview function). Listen for settings that sound only like the noise to be removed. If you hear parts of the sound you want to retain in the noise output, then the settings
are too aggressive. When deselected the Preview & Accept buttons will deliver the processed (residual) sound according to the plugin settings.
The main display window shows a spectral view of the sample to be processed. This represents frequency on the horizontal axis and time on the vertical axis, while color represents intensity.
- Frequency scale - Zooms the frequency scale for more or less precise EQ curve editing or frequency inspection.
The (white) EQ envelope allows a +12 to -24 dB EQ curve to be applied to the selected sample. Time is represented on the vertical axis and Frequency on the horizontal axis.
Apply EQ in addition to the other noise reduction functions to fine-tune the result.
To edit the EQ curve: Right-click in the 'Envelope Editor Window' to add points, and Left-click to move points and tension markers. Right-click points to open a context menu that
allows you to delete points or change the curve type. The default mid-line is 'no change'. Boost/Cut values appear in the FL Studio Hint Bar as the nodes are moved.
If you need a dedicated equalizer use the Equalize tool.
- Reset - Resets the EQ envelope to the default state.
- Envelope options (small right facing arrow under the EQ display window).
- Open state file / Save state file - Opens/saves envelope states. Several different pre-defined state files are available.
- Copy state / Paste state - Use this to copy and paste envelopes, usually between instances of the EQ editor across open Edisons.
- Undo - Undoes the last envelope edit.
- Undo history / Last reset - Shows the editing history since the last reset.
- Flip vertically - Inverts the current envelope.
- Scale levels - Opens the Scale Level tool.
- Normalize levels - Scales the envelope so the highest and/or lowest levels reach +/- 100%.
- Decimate points - Opens a simple tool that allows manipulation of the number of control points in the envelope (useful in conjunction with Analyze audio file).
- Filter - Opens the Envelope Filter tool (useful in conjunction with Analyze audio file).
- Smooth up - Opens the Smooth Up tool that allows smoothing of the envelope shape (useful in conjunction with Analyze audio file).
- Smooth up abrupt changes - Quick removal of 'spikey' or sudden changes in the envelope.
- Turn all points smooth - Preset filter to quickly filter the envelope.
- Create sequence - Opens the Envelope Sequencer tool.
- Analyze audio file - Open, analyze and replicate the volume envelope of an input sound file. Drag and drop audio files directly on the Envelope editor for automatic analysis.
To activate ensure the Denoiser button is selected. The Denoiser is designed to reduce or remove constant background noises in recordings. This background noise can include tape hiss, microphone hum, power mains buzz, camera motor noise, air-conditioning
rumble and any other type of noise that doesn't change in level or frequency significantly throughout the recording.
- Threshold - Controls the separation of noise and desirable signal levels. Higher threshold settings reduce more noise, but also may suppress low-level desirable components of the signal (select the Output noise only switch to hear the sound being removed).
A lower threshold preserves low-level signal details, but can result in noise being modulated by the retained sounds. A good default is 0 dB.
- Amount - Controls the level of noise suppression in decibels. Strong suppression can degrade low-level residual audio, so it's recommended to apply only as much suppression as needed to reduce the
target noise to the level that is barely noticeable (click the Preview button to audition various settings prior to applying the noise reduction). Remember, if the sound is to be used in a mix, then it is likely
that less suppression will be needed to render the noise inaudible.
Using the Denoiser:
- Noise profile - The Denoiser needs to hear an example of the background noise, preferably in isolation from other sounds, so that it can generate an accurate 'noise profile'. From main Edison sample
window, select a section of the sample that contains only noise (if possible). Examine the start and end of the sample, where noises are usually exposed. Alternatively, you may need to select regions in the sample
where there are pauses in the desirable sound (breaks in speech or singing for example). If a 'noise-only' region can't be found, select a quiet section of the sample where the noise is at its most audible. After selecting
the longest section of noise that you can find, Right-click the Clean up (denoise) button to create the noise profile. If the Noise Removal Tool is open, click the Acquire noise profile button to select the
- Select the region to be processed - Prior to returning to the Denoiser interface, make sure that the region you want to denoise is selected in the main Edison sample window (the Denoiser will retain the
noise profile so it is OK to close the Denoiser to select the region to be processed). If no region is selected the whole sample will be processed, this is usually the desired outcome as processing small sections of a
sample can lead to audible tonal changes at the boundaries of the processed region.
- Preview the settings - Open the Denoiser Tool and preview the default settings by clicking on the Preview button. Note the noise profile will appear in the Denoiser as a green frequency curve
(see the screenshot above).
- Fine tune the controls - Sometimes you may hear 'underwater' artifacts of the noise reduction process, if so you should continue to adjust first the Threshold and then the Amount
settings. You should apply only enough reduction (Amount) to make the noise barely or not noticeable in the context for which the sound is to be used. Excessive amount settings are guaranteed to cause audible
artifacts. It is often useful to select the Output noise only button to more clearly hear the parts of the sample being removed. Ideally only noise will be heard.
- Accept the result - Once you are satisfied with the settings.
- Practice makes perfect - If you would like to experiment, the sound 'Maximus NoiseGate Tutorial 44kHz.wav' is a
vocal mixed with some power-supply hum, exposed at the end of the sample. To download the file you will need to create a logon at freesound.
The freesound project is an initiative of the Music Technology Group of Pompeu Fabra University to build a library of Creative Commons licensed sounds.
To activate ensure the Declipper button is selected. The Declipper can repair digital and analog clipping artifacts that result when A/D converters are overloaded or magnetic tape is over-saturated.
The Declipper can be extremely useful for saving recordings that can't be re-recorded such as live concerts, interviews or one-off audio events.
- Threshold - Selects the clipping level used for detection of clipped peaks. The ideal setting is a level just below the actual level of clipping, you can examine the waveform in the main Edison window and
inspect the clip level by hovering the mouse over the clipped waveform.
NOTE: The Declipper re-creates peaks above the clipped level and will therefore reduce the overall volume of the recording to provide headroom for this process. In light of this, declipping usually needs to be applied to the entire
recording in order to avoid a sudden drop in volume in the processed region.
To activate ensure the Declicker button is selected. The Declicker is useful for restoring for old vinyl and other recordings that cause clicks, pops and/or crackles. The Declicker can also remove a variety
of short noises from other sources, including some clicks caused by digital errors or electrical interference. The Declicker works best on click-transients of 10 ms or less.
- Sensitivity - Controls the aggressiveness of the click detection algorithm. Low values of this parameter will remove fewer clicks, while higher values may treat musical transients as clicks, resulting in distortion.
- Accept - Processes and pastes (replaces) the original selection.
Interface: Didier Dambrin.