Sorry for stealing this. So it considers vinyls that are pressed with tracks that are cut at around 20khz as mp3?
I got 2 set of FLACs and a MP3
1 FLAC is a vinyl rip (first stored as 24-bit WAV and then compressed to a 24-bit FLAC)
1 FLAC that's a "remaster" (based on the labelowner's words)
and
1 MP3 that goes up to 22khz.
First example is my vinyl rip. This one (with more from the same artists) have most likely used a cutoff filter some kind, as most of these vinyls predates the wider use of MP3.
Second example is from a remaster bundle that was sold in wav format, but clearly contains mp3 compression artifacts. FTF detects this as alright because there isn't a clear cut off because the remasters ups the ante on the artifacts (even though visible there is a clear cut-off)
Third and last example is a MP3 from a label where quite a lot of the mp3's are filling the spectrum with no clear compression artifacts. If I were to trans-code this to a FLAC, I doubt FTF would know it was from a MP3... which it didn't, as it said the file wasn't fake (when I clearly trans-coded it from a MP3!)
Note: I am using Foobar2k to see if a file is really fake or not, as it's the only tool I have compared to spek and FTF that actually shows mp3 artifacts at higher freq.