I have purchased custom subliminal cd's and I have using them for over 3 months now and I am not sure if the message I wanted on it is even on there or what message is on there and or even if there is a message period. How can I find the message in the background. I just want to make sure I'm not being ripped off.
Subliminal CDs are pretty much a rip-off. The science is weak, but even if you did want to uncover the "subliminal" message, it'd take a ton of work (think of isolating vocals from a mixed down song). Since some of the methods for encoding the message involve reversing it or placing it outside the human hearing threshold (plausible deniability :D), this complicates things greatly. Get your money back as soon as possible.
Find the exact same recording (sans subliminal) and match up the first zero-crossing. Invert one of them. Anything left over is the difference between the two signals. If you have nothing, then there's nothing there. If you have more, then hopefully there's not too much left that makes it impossible for you to distinguish them.