Clearly your system can easily distinguish a lossy from lossless.
You mind taking a lossless file, convert it to 320kbps CBR with LAME, and do ABX testing and print screen your score?
Some years ago my son, who is an electrical engineer and I did a research project into lossy codecs as. We found that in my Grand Forks ND studio, we could tell lossy codecs like mp3 320 kbps. We played wav. files and converted files double blind from wave lab, and both of us could tell the two 100% of the time.
With my new rig it is even easier, the recognition is instant.
Now we chose well recorded music from ambient spaces for evaluation.
You have to understand that these are speakers that present a huge sound stage, with depth, that really gives the effect of walls opening on good recordings.
Our researches showed among other ills that lossy codecs threw out a lot of the ambient information preferentially. We came to the conclusion that these codecs were pop industry geared. That they certainly are.