Quite right. After mastering, the general view of the marketing people is that 40dB is about the right level of dynamic range to offer the customer, even for big, dramatic orchestral works. I quizzed a record executive about this and he said that they get customer complaints along the lines of ‘the quiet bits are too quiet and the loud bits too loud’ if they exceed 45dB dynamic range on a CD!
In the rock and pop world, record companies are facing a ‘who gets to sound loudest on the radio’ syndrome and all the effort is put into compression technology to try and squeeze the dynamic range down to 0.5dB - I kid you not! However what I have found surprising is that even in these releases the actual instrument dynamics seem to be very good. If you analyse these recordings with frequency discrimination you can see that, although the overall envelope is held to under 1dB dynamic range, individual instrumental sections have much wider dynamics. The human ear/brain system is able to unravel these dynamics, thanks to the construction of the cochlea, so we shouldn’t be dismissive of the recording or the mastering.
BTW, it is in the mastering, for commercial release, that the dynamic range is decided. I’ve talked to record producers who have complained that the CD masters are often a poor representation of the recording. I live in hope that streaming and MQA will solve this issue.
In the final analysis it is true that there is little point in having greater than 16-bit depth for music’s dynamic range in reproduction apparatus, so the real purpose of 24-bit file depth is to give the high resolution DACs an easier workflow and a lower digital noise floor, as I’ve hinted at. There are real gains, however, to be had in moving from 44kHz to 96kHz, but that’s another discussion entirely and not part of this thread.