[WalkmanA17]

Hello from Vietnam,
 
I just have got an Album: "Uptown Special 2015" -  FLAC - 16/44.100 from my friend. I used Spectro to check those files and I saw it was cut off from below 21.5 khz.The next thing I used AudioChecker to find out and it said those audio files were MPEG. So I when to HDTrack and bought Uptown Special in 24bit as WAV then converted those WAV to FLAC 16 bit - 44.100 hz using dBpoweramp. I checked those converted WAV to FLAC with Spectro again and it showed those audio files was cut off between 22.1 khz and above 21.5 khz. Audiochecker showed my WAV to FLAC files were CDDA.
 
Here is some images:
 
http://imageshack.com/a/img661/3725/q85Zaf.jpg image 1 - From HDTrack
http://imageshack.com/a/img903/5968/g0coFl.jpg image 2 - From my friend
 
So i guess that below 21.5 khz is an upscale file, right?

 

[flatmap]

Welcome to headfi, WalkmanA17!
 
I'm not an expert, but I believe that a 44.1 kHz sample rate isn't capable of representing anything higher than about 22 kHz.
 
Take a look at https://en.wikipedia.org/wiki/Nyquist_frequency  
 
Hope that is helpful.