Bitsonic Sound Recovery [top]
Before AI, "Bitsonic" style tools used phase cancellation and frequency filtering. If you are interested in the math behind traditional "Voice Removal" (often called Center Channel Extraction):
You might be referring to one of the following: bitsonic sound recovery
Originally released as a freeware VST plugin and standalone application, it has become a "hidden gem" for forensic experts and audio archivists. Description Before AI, "Bitsonic" style tools used phase cancellation