envelopevääristymiä

Envelope distortion, known in Finnish as "envelopevääristymiä," refers to undesirable changes in the dynamic contour of a sound signal. This contour, also called the amplitude envelope, describes how the loudness of a sound varies over time. Envelope distortion can occur during the recording, processing, or reproduction of audio.

Common causes include faulty audio equipment, such as worn-out tape heads in analog systems or digital clipping in digital systems. Improper gain staging, where signal levels are too high, can lead to clipping, which flattens the natural peaks and valleys of the envelope. Similarly, aggressive compression or limiting that is not properly applied can also alter the envelope in unintended ways, making the sound unnaturally flat or creating pumping artifacts.

The perceptual impact of envelope distortion varies. Clipping, for instance, introduces harsh harmonics and a loss of transient detail, making the sound distorted and fatiguing. Overly smoothed envelopes can make a sound feel lifeless or lacking in punch and impact. In contrast, intentional manipulation of the amplitude envelope is a fundamental aspect of sound design, used in techniques like envelope shaping and modulation to create dynamic and expressive sounds. However, when these changes are unintentional and degrade the signal's fidelity, they are classified as envelope distortion.