I have two files from the same source. This one passes Fakin’ The Funk:
This one doesn’t pass Fakin’ The Funk:
Both exceed 20,000 Hz and seem to have similar flat profiles except that one rises to 21,878 Hz and the other only to 20,498 HZ. It doesn’t look to my inexperience eye like the cut-off at the top is very sharp... small red spikes appear to exceed the stated cut-off frequency. Could it be that the song was simply recorded this way or is it because it is too far below 22,100 Hz that makes it a fake?