SlackBuildsOrg/audio/spectmorph

SpectMorph is a free software project which allows to analyze samples
of musical instruments, and to combine them (morphing). It can be
used to construct hybrid sounds, for instance a sound between a
trumpet and a flute; or smooth transitions, for instance a sound that
starts as a trumpet and then gradually changes to a flute.
In its current version, SpectMorph ships with many ready-to-use
instruments which can be combined using morphing.