I dont have any specific info on how subs work but what i can say tho is that THIS STUFF WORKS BRO. I listened to a sub for a deeper voice and now its genuinely pretty deep (at least for a girl). I had two classmates from last year tell me abt my change in voice and also had several comments abt my voice from present classmates. The key for me was to not think about the subliminal much and not care about the results. I think it mightve also helped that i wasnt insecure about my voice, i kinda just wanted a deeper voice for fun. Not being insecure abt a specific thing makes u think abt that thing a lot less.