It's not JUST line in recordings. They're GOOD line in recordings.
If you try to line-in a Genesis game, all you hear is the background noises and stuff. If Protoman did JUST that, it'd sound like crap. He, however, did an awful lot of de-noising AND he recorded it on a Nomad. He knows his stuff.
Neothe0ne is speciallized on newer systems like gamecube and PC rips.