There is no humanly measurable difference. This was established as far back as the early 90's when the technology was in preliminary testing. People saying that you can buy high end gear to tell a difference are probably just rationalizing their investments with placebo.
Using classical music as a benchmark for compression is a bit funny and misguided, because typically that sort of music plays along very nicely with compression algorithms. It's music with very fast and sharp high end transients that are more difficult to process. "Rich and multi-layered instrumentation" can be used to describe most types of productions that aren't barebones garage rock. There is nothing special or magical that somehow elevates it on a technical level (besides the fact that it is more likely to avoid being dynamically compressed to hell).
I can tell the difference between Mp3 and FLAC with classical music and or anything involving rich and multi-layered instrumentation.
Listen to the album Thriller in mp3. Do it again in FLAC. You should notice a difference.
Using classical music as a benchmark for compression is a bit funny and misguided, because typically that sort of music plays along very nicely with compression algorithms. It's music with very fast and sharp high end transients that are more difficult to process. "Rich and multi-layered instrumentation" can be used to describe most types of productions that aren't barebones garage rock. There is nothing special or magical that somehow elevates it on a technical level (besides the fact that it is more likely to avoid being dynamically compressed to hell).