What do you all use to play music/cd's???

[Durentis]

Originally Posted by mx2004

Incorrect. CDs contain uncompressed Linear PCM at 16 bits / 44.1 kHz.

You can argue semantics until you're blue in the face, but the fact remains - sample rate is a first stage compression. More accurate would be for you to say that CDs contain un-recompressed Linear PCM at 16 bits / 44.1 kHz, but that's kinda trivial given that anything is an un-recompressed form of itself.

But I suspect that recordings are often done at higher than CD spec and later altered to CD spec (say, by pulling out every other frame to cut the sample rate in half). It would be like retaining a 4K master but cutting it back to 1080p for distribution. This subsampling is again a compression.

There are many ways to compress audio and removing entire frames (samples) is one of them. Whether it happens in the second stage compression or right from the initial recording, it is still compression.