Spectral delays have been used for a long time as a way to colour and shape spectral characteristics of sound. Most of available software is controlled by drawing an envelope on a window that represents spectral bins, and by setting a max- imum delay time. Despite its comfort, such a simplistic approach does not imply any methods for allowing symbolic manipulations on spectral data that are often required by composers and sound designers. Chromax proposes an alternative dynamic parameterization of spectral delays, allowing fine and complex compositional manipulations. It implements a bin-synchronous spectral processing using the new Gen~ technology available in Max6, and provides algorithms to dynamically specify a filter, a delay and a feedback level for each bin of a processed sound.