If you take a listen to Leo's vids for example, whatever you hear when the NULL test is done (when the signals have opposite phase) is what the profiling is missing. If the signals would be identical, a Null tests would rendered silence.
If the stuff you're hearing is a noticeable part of the frequency spectrum, then accuracy isn't as good and you're most likely going to be able to tell a difference.
If whatever you hear is just static etc then it means the profile is pretty spot on.
Just my 2c.
