[HN Gopher] How to date a recording using background electrical ...
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How to date a recording using background electrical noise
Author : sebg
Score : 103 points
Date : 2023-02-24 05:29 UTC (1 days ago)
(HTM) web link (robertheaton.com)
(TXT) w3m dump (robertheaton.com)
| greenyoda wrote:
| Some discussion from yesterday:
| https://news.ycombinator.com/item?id=34925583
| sliss wrote:
| Curious if this can be used to discern AI-generated voice
| recordings vs authentic.
|
| A determined faker could always add their own noise, but this be
| a good first-pass detector.
| hummus_bae wrote:
| [dead]
| vimax wrote:
| A recent approach along these lines is to do acoustic modeling
| of the vocal tract that would have produced the speech.
| Unsurprisingly, AI voices do not correspond to realistic human
| vocal tracts, for now.
|
| https://www.usenix.org/conference/usenixsecurity22/presentat...
| atoav wrote:
| So yet another argument for proper, balanced audio recordings and
| working noise gates.
| Groxx wrote:
| A video on the same subject: https://youtu.be/e0elNU0iOMY
|
| I really enjoy Tom Scott. Everything he puts out is _wonderfully_
| concise.
| cynwoody wrote:
| Yes, Tom Scott is one talented YouTuber.
|
| See, for example, his video on microwaving frozen hamsters back
| to life[0], in which he interviews the 101-year-old J. E.
| Lovelock, the scientist who did the work back in the fifties.
|
| [0]https://www.youtube.com/watch?v=2tdiKTSdE9Y
| moremetadata wrote:
| His company accounts would suggest he's popular.
| antegamisou wrote:
| I like the guy too but not a big fan of the whole dumb-it-
| down/ELI5 culture. Some subjects absolutely require a lot more
| (written text, experimentation/tweaking with code) than few
| fancy videos to grasp.
| tverbeure wrote:
| A dumbed down version is great to introduce people to the
| subject
|
| Chances are that good written explanations already exist,
| just a Google search away, for those who want to learn more.
|
| Tom's video and this blog post are perfect combo that
| complement each other.
| Groxx wrote:
| Dumbed down without being _inaccurate_ is also often
| sufficient for anyone with some base knowledge in an area.
| You can figure a lot out simply by being told the core
| concept, no need to go into extreme detail.
|
| Extreme detail is great for those that want or need it, but
| it's far from the only reasonable option for learning
| things.
|
| ---
|
| Re the general flood of these kinds of videos: oh yeah, I
| think it's excessive. I suspect YouTube is pushing that
| category lately (which is FAR from the worst to push, so
| I'm largely okay with that). It feels like all the popular,
| algorithmically pushed ones are making sure to cross the
| magic 10 minute mark, and try to look like TV/movie
| editing, regardless of what those do to the content. Bonus
| points for obtuse video titles that tell you nothing about
| what topic is covered.
|
| Which is part of why I like his. They almost never hit 10
| minutes, or even close. There's little fluff, little drama,
| little algorithmic gaming - videos today look very similar
| to several years ago.
| sebzim4500 wrote:
| IIRC the reason they aim for the 10 minute mark is
| because they can put in mid roll ads, not because the
| algorithm wants it.
| acchow wrote:
| Have you tried any 3Blue1Brown videos? Highly recommend
| antegamisou wrote:
| Yes and I believe their videos are one the best things on
| the Internet right now as far as math education is
| concerned. Same goes for {Computer,Number}phile.
|
| The reason they're high quality learning material is
| because the explanations of the various concepts respect
| weaker math backgrounds, without being desperate to be as
| reductive as possible or have clickbaity titles , and
| sometimes with downright wrong claims, to generate more
| audience.
|
| An example of a channel that consistently follows this
| latter pattern is Veritasium i.e. see the electricity video
| controversy.
| Groxx wrote:
| Yeah, Veritasium was more alright a while back, but
| they've gone WAY off the deep end nowadays. Beyond merely
| "no longer interested in their content", I think they
| might be actively damaging at this point.
| vasco wrote:
| All subjects have non-dumbed down versions in research
| papers, university level books or industry reference manuals.
| The existence of more dumbed down content doesn't make those
| disappear.
| cynwoody wrote:
| Right below the author's comment, "Regardless of a grid's size,
| the current flowing through it oscillates in perfect synchrony,
| at exactly the same frequency, throughout the whole grid," he
| presents a map of Western Europe's regional groups. I notice that
| Finland, Sweden, Norway, and Iceland comprise the Nordic Regional
| Group.
|
| Iceland? There is a lot of water between Iceland and the other
| three nations in its group. Is Iceland's power indeed
| synchronized with the other three? If so, why does it need to be?
|
| Below the map, the author includes a link crediting the Wikipedia
| article on power grids[0], which includes maps of other regions
| in the world.
|
| Perusing the map for North America, I notice another
| noncontiguous regional group, namely the Alaska group. Most of
| Alaska is off the grid (or, more accurately, on a collection of
| local grids too small to be named). The named group includes a
| slice of the interior extending northward from Anchorage towards
| Fairbanks and a separate noncontiguous area containing Juneau. I
| have the same question, are the two sub-regions synchronized?
|
| [0]https://en.wikipedia.org/wiki/Wide_area_synchronous_grid
| [deleted]
| lordnacho wrote:
| Great article. Something in me finds satisfaction when I
| recognised something I learned about at uni applied in the real
| world.
|
| Now on to building an ENF spoofing machine that people can carry
| around with them to confuse eavesdroppers.
| justinclift wrote:
| Sounds like anyone wanting to do a "proper" fake job will now
| need to separate out any existing hum, then add a new continuous
| "hum track" based upon those publicly available ENV values.
|
| Probably wouldn't even be all that hard.
| ComputerGuru wrote:
| By itself? No. But this is just one more thing that can be used
| to date a recording. If you even know about it.
|
| There are hundreds of known fingerprints and you just need to
| forget about or not know of just one for your fraud to be
| called out.
| dfox wrote:
| > Regardless of a grid's size, the current flowing through it
| oscillates in perfect synchrony, at exactly the same frequency,
| throughout the whole grid
|
| I have a feeling that this is not exactly true. The grid is
| composed of transmission lines (in the "wires on pylons sense"),
| that are on one hand short enough that they do not really behave
| like transmission lines (in the circuit analysis sense), but on
| the other hand long enough that their propagation delay and other
| "RF-like" properties are somewhat interesting for design of
| efficient grid.
|
| On the other hand, the phase shifts and related distortion
| effects are outside of the bandwidth of the audio recording as
| long as the grid is at least somewhat properly designed.
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