Understanding and applying stereo imagery effects

Some effects let you change the apparent location, or stereo imagery, of sounds coming from the speakers.

Center Channel Extractor effect

The Stereo Imagery > Center Channel Extractor effect keeps or removes frequencies that are common to both the left and right channels—in other words, sounds that are panned center. Often voice, bass, and lead instruments are recorded this way. As a result, you can use this effect to bring up the volume of vocals, bass, or kick drum, or you can remove any of them to create a karaoke mix.

Extraction tab

Limits extraction to audio that meets certain properties.


Either select audio in the Center, Left, Right, or Surround channel, or select Custom and specify the precise phase degree, pan percentage, and delay time for audio you want to extract or remove. (The Surround option extracts audio that is perfectly out of phase between the left and right channels.)

Frequency Range

Sets the range you want to extract or remove. Predefined ranges include Male Voice, Female Voice, Bass, and Full Spectrum. Select Custom to define a frequency range.

Discrimination tab

Includes settings that help identify the center channel.

Crossover Bleed

Move the slider to the left to increase audio bleed through and make the sound less artificial. Move the slider to the right to further separate center channel material from the mix.

Phase Discrimination

In general, higher numbers work better for extracting the center channel, while lower values work better for removing the center channel. Lower values allow more bleed through and may not effectively separate vocals from a mix, but they may be more effective at capturing all the center material. In general, a range from 2 to 7 works well.

Amplitude Discrimination and Amplitude Bandwidth

Sum the left and right channels, and create a perfectly out‑of‑phase third channel that Audition uses to remove similar frequencies. If the amplitude at each frequency is similar, in-phase audio common to both channels is also considered. Lower values for Amplitude Discrimination and Amplitude Bandwidth cut more material from the mix, but may also cut out vocals. Higher values make the extraction depend more on the phase of the material and the less on the channel amplitude. Amplitude Discrimination settings between 0.5 and 10 and Amplitude Bandwidth settings between 1 and 20 work well.

Spectral Decay Rate

Keep at 0% for faster processing. Set between 80% and 98% to smooth out background distortions.

Center and Side Channel Levels

Specifies how much of the selected signal you want to extract or remove. Move the sliders up to include additional material.

Advanced options

Click the triangle to access these settings:

FFT Size

Specifies the Fast Fourier Transform size, with low settings improving processing speed, and high settings improving quality. In general, settings between 4096 and 8192 work best.


Defines the number of FFT windows that overlap. Higher values can produce smoother results or a chorus‑like effect, but they take longer to process. Lower values can produce bubbly‑sounding background noises. Values of 3 to 9 work well.

Window Width

Specifies the percentage of each FFT window. Values of 30% to 100% work well.

Graphic Phase Shifter effect  

The Stereo Imagery > Graphic Phase Shifter effect lets you adjust the phase of a waveform by adding control points to a graph.


Right-click points to access the Edit Point dialog box for precise, numerical control.

Phase shift graph

The horizontal ruler (x‑axis) measures frequency, while the vertical ruler (y‑axis) displays the degree of phase to shift, where zero is no phase shift. You can create simulated stereo by creating a zigzag pattern that gets more extreme at the high end on one channel.

Frequency Scale

Sets the values of the horizontal ruler (x‑axis) on a linear or logarithmic scale. Select Logarithmic to work at finer detail in the lower frequencies. (The logarithmic scale better reflects the frequency-emphasis of human hearing.) Select Linear to work at finer detail in the higher frequencies.


Sets the values of the vertical ruler (y‑axis) on a 360° or 180° scale.


Specifies the channel(s) to apply the phase shift to.


Process a single channel for the best results. If you apply identical phase shift to two stereo channels, the resulting file sounds exactly the same.

FFT Size

Specifies the Fast Fourier Transform size. Higher sizes create more precise results, but they take longer to process.

Stereo Expander effect  

The Stereo Imagery effect positions and expands the stereo image. Because the Stereo Expander is VST-based, however, you can combine it with other effects in the Mastering Rack and Effects Rack. In Multitrack View, you can also vary the effect over time by using automation lanes.

Choose Effects > Stereo Imagery > Stereo Expander, and set the following options:

Center Channel Pan

Positions the center of the stereo image anywhere from hard left (-100%) to hard right (100%).

Stereo Expand

Expands the stereo image from Narrow/Normal (0) to Wide (300). Narrow/Normal reflects the original, unprocessed audio.