I think there's still room to have doubts, and I see nothing wrong with wanting further verification. I'm willing to believe that perhaps CD audio is as far as we need to go with 2-channel, but for whatever reason, I find a lot more demo material in my SACD collection than in my whole CD collection. I'm willing to accept that this could merely be the extra channels at work, or a coincidental superior sound engineering for those discs, but it doesn't change the fact that from an audio quality perspective, I'm getting more out of a format that isn't CD. So, while I'm willing to go along with the idea that CDs CAN provide for the full range of human audibility, I'm still not 100% certain that there's not more to it.
