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Modulation effects

Unlike some of the previous effects we’ve discussed, modulation effects aren’t designed to solve problems as much as add “spice” to sounds in the form of special effects. These effects tend to produce very specific sounds, and the presets included with Adobe Audition are a good place to start. Therefore, with most of these effects, you’ll load presets to hear how they affect the sound and also analyze which parameters are most important for editing.


Chorus can turn a single sound into what seems like an ensemble. This effect uses short delays to create additional “voices” from the original signal. These delays are modulated so that the delay varies slightly over time, which produces a more “animated” sound.

  1. Choose File > Open, navigate to the Lesson04 folder, and open the file FemaleChoir.wav. Play the file to hear what it sounds like.
  2. Click an effect insert’s right arrow, and choose Modulation > Chorus.
  3. Note how with Chorus enabled the Default preset creates a fuller and bigger sound. Select Highest Quality: Most modern computers can provide the additional processing power this option needs. If the audio crackles or breaks up, deselect this option.
  4. Increase Modulation Depth to 8dB or so. Notice how the sound becomes more animated. To make this more obvious, increase the Modulation Rate to 2.5Hz. Modulation Depth and Rate interact; with a higher Rate, you’ll usually want a lower Depth. Return Modulation Depth to 0.
  5. To increase the “number of people” in the chorus, click the Voices drop-down menu and choose 16 voices. Because this adds a lot more audio, you may need to bring down the Output control in the Effects Rack panel to avoid distortion.
  6. Set the Delay time to around 40ms for now. Increasing the Delay Time can make a bigger sound, but too much Delay Time may produce an “out of tune” effect.
  7. Set Spread to around 152ms. Spread increases the stereo image width. Bypass/enable the Chorus to hear the effect of these edits.
  8. With Chorus enabled, note the Dry and Wet Output level controls. For a more subtle effect, set a higher Dry value and lower Wet value, or turn up only the Wet sound for the most “diffused” character.
  9. Turn up the Feedback parameter but be careful, because even slight amounts can add uncontrolled feedback. Values up to about 10 can produce a more “swirling” sound for the Chorus.
  10. The remaining controls apply to stereo imaging. Adjust Stereo Field to make the output narrower or wider. Select Average Left & Right Channel Output and Add Binaural Cues; if you like the sound better, leave them selected. If there’s no audible difference, leave them deselected. Leave Average Left & Right Channel Output deselected if the original signal was mono.
  11. To get a sense of how you can also use the Chorus effect for special effects, try selecting other presets, like Chaos Pits and Robotic Bee Attack. Note that some of the more bizarre sounds combine lots of modulation, feedback, or long delay times.
  12. Leave the project open in preparation for the next lesson.


Like Chorus, Flanger uses short delays, but they’re even shorter to create phase cancellations that result in an animated, moving, resonant sound. This effect was popularized in the 60s due to its “psychedelic” properties.

  1. Click the current effect insert’s right arrow, and choose Modulation > Flanger to replace the Chorus effect. Play the file to hear what it sounds like.
  2. For a more pronounced effect, set the Mix to 50%. Alter the Feedback setting; more feedback produces a more resonant sound.
  3. Set Stereo Phasing, which changes the phase relationship of the modulation, to 0; the modulation is the same in both channels. Increase the Phasing amount to offset the modulation in the two channels, which creates more of a stereo effect. Vary the Modulation Rate to change the modulation speed.
  4. Experiment with the Initial Delay Time and Final Delay Time options, which set the Flanger sweep range. The “standard” range is 0 to around 5ms; increasing the final Delay Time produces a sound that’s more like chorusing when the Flanger delay time reaches the longer delay.
  5. Use the Mode options for specialized effects. Selecting Inverted changes the tone. Special Effects changes the flanging “character”: Enable it and see if you like what it does. The effect varies depending on the other parameter settings. Sinusoidal changes the modulation waveform to produce a somewhat more “rolling” modulation effect.
  6. Load other presets to get a sense of the range of possibilities that the Flanger can offer. Many of the more radical patches use either high Modulation Rates, large amounts of Feedback, longer Initial or Final Delay Times, or a combination of these.
  7. Leave this project open in preparation for the next lesson.


Chorus/Flanger offers a choice of Chorus or Flanger; each is a simpler version of the Chorus and Flanger effects described previously. Width is essentially the same as varying Delay in the Chorus or Flanger, whereas Intensity basically determines the wet/dry mix. Speed provides the same function as Modulation Rate. The only different control is Transience, which emphasizes transients to produce a “sharper” sound.

  1. Click the current effect insert’s right arrow, and choose Modulation > Chorus/Flanger to replace the Flanger effect.
  2. Load the various presets to hear the types of effects each processor provides.
  3. Leave Audition open in preparation for the next lesson.


The Phaser effect is similar to Flanging but has a different, and often more subtle, character because it uses a specific type of filtering called an allpass filter instead of delays to accomplish its effect.

  1. Assuming that Audition is open and the FemaleChoir.wav file is loaded, click the current effect insert’s right arrow, and choose Modulation > Phaser to replace the Chorus/Flanger effect. Play the file.
  2. Phasing tends to be most effective when you’re processing the midrange, so change the Upper Freq to around 2000Hz.
  3. Move the Phase Difference away from the center (0) position to widen the stereo image (as with Flanging, you can offset the modulation for the left and right channels). Leave this parameter at 180 for now.
  4. Moving Feedback off-center to more positive values increases the phaser’s sharpness, producing a “whistling” sound. More negative values produce a subtler, “hollower” sound. Leave it at 0.
  5. Vary the Mod Rate slider. Note how at faster settings the effect is almost like vibrato. Return it to 0.25Hz before proceeding.
  6. Experiment with the remaining parameters to set the degree of “drama” in the phased sound:

    • More Stages produces a more profound effect.
    • Intensity determines how much phase-shifting the Phaser applies (you’ll typically want this above 90 unless you prefer a more “static” sound).
    • Depth sets the lower frequency limit that Modulation attains. This complements the Upper Frequency parameter, which is the highest frequency that Modulation attains.
    • Mix sets the blend of wet and dry sounds. A 50% value produces the maximum phasing effect by mixing dry and wet signals in equal proportion. Moving the value toward 0 increases the proportion of dry signal to wet signal, whereas moving the value toward 100 increases the proportion of wet signal to dry signal.
  7. Load the Phaser’s various presets to hear the different types of effects it can provide.
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