  In this article indicators to describe the "beauty" of noises are proposed.
Rhythmic, tonal and harmonic suavity are introduced. They give a
characterization of a noise in terms of rhythmic regularity (rhythmic suavity),
of auditory pleasure of the "chords" constituting the signal (tonal suavity)
and of the transition between the chords (harmonic suavity). These indicators
have been developed for periodic noises typically issued from rotating machines
such as engines, compressors... and are now used by our industrial customers
since two years.
