Do subconscious messages work if I can barely hear them consciously?

I have a subliminal message package that included: A sound mixer, Samples of subliminal messages that I can splice with music. From what the material said from the manual, the subliminal messages need to be turned down to a barely audible level and my subconscious will pick it up. I know the messages are working because I have felt a huge difference only after a couple of days, it maybe because of the Placebo effect but there is research that shows subconscious messages do work. I'd appreciate help on this subject, thank you.