Yes, MP3s are virtually identical. (Destiny)

by Xenos , Shores of Time, Saturday, March 21, 2015, 14:16 (3783 days ago) @ marmot 1333

I'd be curious to read about how you performed your blind test.

I can definitely tell the difference between a 128k mp3 and a CD. Things like cymbal shimmer and hi hats are relegated to some noisey hiss on low-quality encodings.

I think this is going to be where your issue is. Usually the gap between 128 and 256 mp3s are where you can start telling the difference (which is why pretty much everyone that sells mp3s uses at least 256 now). 320 is really the point where even audiophiles start having trouble telling the difference.