this is a very interesting and quite high level sound design challenge. I am making steam whistle sounds for my game and I am using accurate and original recordings of these whistles. this one recording I have is too short for me to work with and its been causing some issues: when I try to extend it out into 1 continuous droan, its not 1 long continuous drone, its turning into some sort of wawawawa effect. Its very hard to describe what exactly I am looking for, so if someone is willing to help me with this project, I can send the whistle recording I am having difficulties with and a different whistle sound that is similar but clearly illustrates what I am trying to achieve with this one particular recording.
#steam train whistle sfx timbre
solid pumice
tranquil sentinel
Perhaps this can be of help:
https://github.com/SamWindell/Signet
Especially:
https://github.com/SamWindell/Signet/blob/master/docs/usage.md#sound-seamless-loop