I found out when digitizing vinyl that LP's before 1977, when digital mixing and mastering was not the norm that there is more data in the frequencies between 20 and 50kHz. I do my recording standard at 192kHz and analogue LP's often reach 48kHz of data while digital mastered ones do only 22kHz. After that date often the frequency is cutoff at 20-22kHz, probably to save memory room. Only after 2000-2010 there is enough memory to record at insane sample rates and bits per sample. Most awful are cds having only 16 bits and 41kHz sample rate, by modern standards really poor.