>which is, as the article states, a challenge even for recording professionals Actually, it calls it an "annoyance", which is a good characterization of it. An

>which is, as the article states, a challenge even for recording professionals Actually, it calls it an "annoyance", which is a good characterization of it. And that's for professionals trying to make very high quality recordings where they accurately capture the output of instruments within that frequency range while eliminating the mains interference in the same range. If you're recording someone's voice on a portable recorder that's in your pocket or stashed somewhere in a room, you're not likely to capture much in terms of voice in that range in the first place. Even if you did, it would still be plausible that you didn't. So if you tampered with a recording and then replaced everything under 70 Hz with ambient noise recorded separately (including mains noise) in the same location, it would be pretty difficult to prove tampering.