The 20 kHz bandwidth of CD audio media may cause truncation of some material. Here is an example of a small amount of energy above 20 kHz in a symphonic recording. It is interesting to note that this is a 7.5 in/s recording done on 1970s prosumer equipment. I’ve said in my presentations for some years, most 7.5 in/s tapes are well-suited to 44.1ks/s 16 bit transfers, but there are exceptions. This shows one.
Whether or not it’s distortion products or real music has been argued by some. I have been transferring most music programs at 88.2ks/s and 24 bits since about 2003. Here is a recent spectral bar graph that shows a 7.5 in/s tape I made in 1974 played in 2005. This shows the peak spectral energy of a portion of Smetana’s Dances from “The Bartered Bride.” Note the energy in the 25k4 band – this came up with cymbal crashes during a crescendo. This is the original master recording using a pair of AKG C-451 microphones feeding a ReVox A77 on Scotch 207 tape.
