Thanks for the help. Should I listen to the same dose over and over, or listen to different ones?

Thanks for the replies! Are there any tips for making them work better (I've read most of the topics about this, but nothing works)? I've seemed to hear music while listening to some of them, but nothing else. What's the longest time it can take for it to work? Are there people who truly are immune ...

I downloaded the free ones, and they all sound the same. I've only listened to about a minute of each one. Is it supposed to be like this? There are a few pitch differences in some of them, but the rest of them sound exactly the same (by the way, I haven't tried it with headphones, I was just listen...