The variability between recordings is to be expected. After all, the original rendering was created in a different room on different speakers than the ones most of us would be using to playback the media. Feel free to use signal processing, on those “weak” recordings. That’s the main reason tone controls exist!

I use my Sony BluRay SACD, DvdAudio player with the coax digital out as my CD player. I figure if it can track and decode a BluRay it can track a CD.