10.6

320Logic Pro Instruments
When you gate speech and vocals with the Noise Gate plug-in, use Threshold to define
the level above which the gate opens, and use Hysteresis to define a lower Threshold level
below which the gate closes. The Hysteresis value is relative to the Threshold level.
Unwanted triggering by low or high frequency noise is avoided by the dedicated sidechain
filters of the Noise Gate plug-in.
Tips to enhance speech intelligibility
Keep these points in mind to achieve the best possible speech intelligibility:
• The spectra of the analysis and synthesis signals should almost completely overlap.
Coupling low male voices with synthesis signals in the treble range doesn’t work well.
• The synthesis signal must be constantly sustained, without breaks. The incoming side
chain signal should be played or sung legato, because breaks in the synthesis signal
stop the vocoder output. Alternatively, the Release parameter of the synthesis signal—
not the Release time of the Analysis section—can be set to a longer time. You can also
achieve nice effects by using a reverberation signal as a synthesis signal. Note that the
two latter methods can lead to harmonic overlaps.
• Do not overdrive the vocoder. This can happen easily, and distortion can occur.
• Enunciate your speech clearly if the recording is to be used as an analysis signal.
Spoken words with a relatively low pitch work better than sung vocals—even if the
creation of vocoder choirs is your goal. Pronounce consonants well, as exemplified
in the rolled “R” of “We are the Robots,” by Kraftwerk, a classic vocoder track. This
exaggerated pronunciation was specifically made to cater to the vocoder.
• You can freely set Formant parameters. Shifting, stretching, or compressing the
formants has a minimal effect on the intelligibility of speech, as does the number of
frequency bands. The reason for this is due to the human ability to differentiate the
voices of children, women, and men, whose skulls and throats vary. Such physical
differences cause variations in the formants that make up their voices. Human
perception, or recognition, of speech is based on an analysis of the relationships
between these formants. In the EVOC20 plug-ins, these relationships are maintained
even when extreme formant settings are used.