Lots of tests have been done, here's a good one:
Running under DOS typically does not give you 100% control over the CPU:
Maintaining contrast with the adverts was the only reason networks didn't remove all the dynamic range from the programming. Now that the contrast is illegal, there's nothing stopping channel vs. channel competition for loudness. Just as election campaigns target the swing voters, TV producers care about the channel flippers, and being louder than the competition is an easy way to grab their attention.
This law has the perverse consequence of making *everything* sound as bad as the adverts.
"The sixties were good to you, weren't they?" -- George Carlin