10. SoundSoap+ Controls

SoundSoap+ provides additional controls for noise reduction that are not in SoundSoap or SoundSoap Solo, and are described in this chapter.

Broadband Noise Range

SoundSoap’s unique Wash Window provides a visual representation of the noise reduction process. The Wash Window displays the frequencies that are in the audio before and after SoundSoap. The lowest frequencies are at the bottom, and the highest frequencies are at the top.  Time advances from left to right.  The black color represents silence, or no energy around a particular frequency.  Red and orange colors represent different intensities of energy around a particular frequency.  A center line divides the oval window into left and right halves, and indicates "before" and "after". Depending on the settings of the Noise Reduction and the Noise Tuner, the Wash Window will give you a visual sense of SoundSoap's noise reduction process.

Visually, removing broadband noise with SoundSoap will take out or reduce some of the red areas. You will notice that the Noise Tuner setting changes what is considered noise based on what is displayed in the Wash Window.

On the right side of the Wash Window, you will see lighter or fewer shades of red than on the left side, depending on the Noise Reduction setting. When Noise Only mode is used, only what is being removed is displayed on the right side of the Wash Window.

The SoundSoap+ Wash Window allows you to control the range of frequencies broadband noise reduction is applied to.  There are two reasons you may want to do this.  First, the frequencies of your background noise may only affect part of the audio frequency spectrum.  Limiting noise reduction to where the noise is provides a better sounding result.  Secondly, you may have discovered that audible artifacts or "warbling" occur as you apply more noise reduction, especially at the lower frequencies.  While the Noise Tuner may allow some control over this, the Wash Window broadband frequency range control allows you to limit noise reduction to a range of frequencies that do not produce as many artifacts.  This also produces a better sounding result.

Click and drag on the Wash Window to set the frequency range high and low frequency that noise reduction will be applied to.  Clicking and dragging in the center of the range you have made allows you to move the high and low ranges together.  SoundSoap+ will display a rectangle where the frequency range has been selected.  Frequencies outside of this range will not have noise reduction applied, and indicates noise reduction only inside of this range on the right side of the Wash Window.


Pressing the Waveform button toggles the Wash Window between a frequency spectrum display and a waveform display.  The waveform display is used to set the threshold setting used by Track and the Downward Expander.

Downward Expander

SoundSoap+ includes a downward expander with adjustable compression ratio and threshold.  The downward expander applies compression, quieting the audio below a given audio threshold level.  This control is a very effective tool for reducing low-level noisy audio.  The rotary compression ration control determines the amount of compression applied to audio below the threshold.  You can set the threshold using the Waveform button (see above).

Hum Harmonics

Usually audio with hum problems includes several harmonics of the fundamental hum frequency. SoundSoap+ lets you control the number of number of hum harmonics removed from the audio.  Move the rotary harmonics knob to set the number of harmonics the SoundSoap hum reduction algorithm uses.  Because hum reduction is a filtering process, you want to listen to the result as you set the number of harmonics so as not to remove more audio frequencies than needed.


Use the lo-cut knob to control the low-frequency cutoff for controlling rumble and other low-frequency issues.  This control removes frequencies below the setting, adjustable between 0-140Hz.  The SoundSoap+ lo-cut knob replaces the "Remove Rumble" setting in the SoundSoap controls.


Use the hi-cut knob to control the high-frequency cutoff for controlling hiss, restricting frequencies beyond the range of vocal material, and other high-frequency issues.  This control removes frequencies above the setting, adjustable between 0-18kHz. The SoundSoap+ hi-cut knob replaces the "Preserve Voice" setting in the SoundSoap controls.

Enhance Presets

The Enhance Slider adds “sparkle” back into the audio signal by boosting frequencies that may have been lost because of degraded media.  SoundSoap+ offers several presets to control which frequencies are boosted.  This can be useful depending on different audio material you are working with in SoundSoap.

L+H - The default Enhance preset included with SoundSoap boosts Lows (0-200Hz) and Highs (6kHz and up)

L+M - Boost Lows (0-250Hz) and Mids (250Hz-6kHz)

M+H - Boost Mids and Highs (500Hz and up)

Lows - Boost Lows (0-250Hz)

Mids - Boost Mids (500Hz-6kHz)

Highs - Boost Highs (6kHz and up)

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