Sparkle - Cross-Synthesis

Sparkle is a tool for advanced spectral hybridizations made of several algorithms that operate on frequency domain. By means of envelope preservation and phase-sync processing it can creates high-quality sound transformations.

The basic idea is to transfer the temporal structure of a sound (source) onto another sound (target) of which the spectral properties are preserved.
Simply put, you can take a voice and make it sing a Beethoven’s symphony!