@lewm
I haven’t “confused” anything. I was referencing early production cdp’s. I thought I said that. Also, of course the term “brick wall” is a metaphor for very steep slope. I probably was remiss in not acknowledging that SACD and DSD ameliorated the problem. But I still hear an unnatural abrupt cutoff of extreme low bass with physical discrete CDs. For whatever reason.
Research doesn’t support me. I was wrong apparently about the low frequency limit built into RBCDs, but I still hear a less natural extreme low frequency response with RBCDs. I have to re-read some 1970s literature to remember why.
No, you simply said digital!
To me this is the perfect example of confirmation bias. You read something in Stereophile decades ago and now authoritatively state that digital has a low frequency cut-off at 22-Hz, which is completely untrue. You only have to understand how digital is formatted to understand this. Or to check out a specification. To the best of my knowledge, there simply is no low frequency limit built into RBCDs, yet you repeat "the low frequency limit built into RBCDs".
You claim you hear this when you go to a concert, so it must be true, but it simply does not exist!
Now it may well be that your digital playback system incorporates a high pass filter somewhere in the chain. DC offsets are not good for speakers, after all.
This is in no way an attack on you personally, because I have high regard for your analogue contributions, it is just an illustration of how audiophile myths can easily become lore.