First piccie is a spectral view of a second or two of a long play minidisc recording.





Next up is a freq analasis of the same file.





Next up the file is encoded to 256 kbps mp3 and decoded back to wav.





This one is a freq analysis of the mp3 sourced wav file above.





Just for comparison, these next images are taken from a dat recording, same song, same show.





Freq analysis...





Encoded to 256 mp3 and back again...





...and Freq analysis...