This chapter describes some applications of the spectral envelope methods and tools developed in this project. It covers both already existing applications and possible applications. These are grouped into applications around additive analysis-synthesis (section 8.1), synthesis of the singing voice (section 8.2), enhancements of the DIPHONE program (section 8.3), applications to real-time synthesis and signal processing (section 8.4), conversion between spectral envelopes and images (section 8.5), and application in voice synthesis by rule (section 8.6).