In this paper we will introduce a tool aimed at assisting composers in orchestration tasks. Thanks to this tool, composers can specify a target sound and replicate it with a given, pre-determined orchestra. This target sound, defined as a set of audio and symbolic features, can be constructed either by analysing a pre-recorded sound, or through a compositional process.We will then describe an orchestration procedure that uses large pre-analysed instrumental sound databases to offer composers a set of sound combinations. This procedure relies on a set of features that describe different aspects of the sound. Our purpose is not to build an exhaustive sound description, but rather to design a general framework which can be easily extended by adding new features when needed.