CDP Sound Examples – ENVELOPING

Envelope transfers

SOURCE SOUNDS

babbling brook
panther cry

TRANSFORMATIONS

panther on brook (amplitude)
panther on brook (spectrum)

DESCRIPTION
~ CDP Functions: ENVEL REPLACE and FORMANTS VOCODE ~

• In the first example, the amplitude contour of the panther's cry is imposed on the sound of the brook. We therefore hear the loudness of the brook rise and fall as did the panther's cry.



• In the second example, the result is quite different. In this case, the changing pattern of frequencies (spectral envelope) of the panther's cry is imposed on the frequency profile of the brook, and we hear some higher frequencies emerge towards the end of the transformed sound.



• The result of the second transformation is more broken up than might have been expected. The frequent dip in amplitude of the babbling brook may be the cause.

Additional Information

PARAMETER SETTINGS
(Click on image to view fullsize)

KEY POINTS

• In ENVEL REPLACE, the extraction and imposition of the amplitude envelope of the second file onto the first is done all at once. Mode 1 specifies that the envelope comes from another sound. It could also come from a binary envelope file, a breakpoint file or a breakpoint file in decibels.



• The window parameter in ENVELOPE REPLACE relates to the resolution of the extracted envelope: smaller values for a finer resolution.



• In FORMANTS VOCODE, it is the channels parameter that determines the resolution of the (spectral) envelope: smaller values for a finer resolution.



• Frequencies below low freq and above high freq are disregarded. I have used the default values here. They can be lowered/raised as required by the input sounds.



• Gain is sometimes needed to compensate for differences in the two signals. It can be applied here, or before or after the vocoding process.

SUPPLEMENTARY FILES USED

No other files are used. None of the parameters are time-varying.

If other types of envelope file are used for ENVEL REPLACE, these are given as the second input.