The SignalEditor is an extensible set of general purpose tools for viewing, analyzing, editing, and
processing sampled signals on the IRCAM Musical Workstation (IMW). Its main intention is to
provide the composer and the scientist with a sophisticated interface to handle digital audio signals
naturally. This involves a high quality graphics interface, a flexible signal analysis system, an
efficient sound file system, and a powerful signal processing environment. In this paper we
discuss a prototype implementation of the spectrogram editing facilities, some aspects of the
editor's extension language and the lowest layer of the sound file system.