The voiced speech sounds (such as vowels) can be regarded as a result of exciting a linear filter (representing a vocal tract) with a pseudo-periodic train of impulses, called pitch excitation (representing vibrations of vocal cords). The impulsive nature of voiced speech formation makes the task of speech declicking and decrackling particularly difficult as pitch-related pulses can be easily confused with noise pulses, i.e. pulses caused by clicks or record scratches.
A special routine was designed to block the outlier detector in instances where pitch excitation is expected. In order to activate this device you should choose the music & speech option from the DeClick Plus dialog.
As general guidelines use the following:
The music & speech version of the renovation program applied to the restoration of instrumental or vocal music will generally work slightly slower than the corresponding music version. Additionally, it may produce slightly inferior results - due to the 'detector masking' effects, some of the clicks may be overlooked.