Engineers create synthetic, sound-silencing structure that blocks 94% of sounds
eurekalert.org
eurekalert.org
Still very cool, and extremely useful for sources like turbines and HVAC systems that are primarily one or two frequencies, but it's hardly a cone of silence; it won't block out your co-workers anytime soon.
With a 10Hz 3dB point, the bandwidth is 20Hz. Your typical engine exhaust has an acoustic spectrum bandwidth of about 150Hz so a stack of 15 of these would allow you to overlap your filters by 5Hz on either side and notch the entire spectrum out. Depending on how much back pressure it put into the system that could pretty effectively quiet a generator or a turbine.
[1] https://www.lencore.com/Portals/5/Lencore_Docs/Article_Under...
Only high mass can do that, the waves pass straight through everything else.
By the way we have these, they're called bass traps.
Bass traps work by eating up the energy in pressure waves that hit them, there's a lot of waves that don't hit them.
Which means that bass traps are only good for minimizing resonances inside an enclosed room, not to stop bass from reproducing through walls or materials.
I don't understand how it'd be implemented, in say, an open office?
As neat as this is, there are a lot of cases where sound is advantageous for us humans regardless of when it being annoying, it often can pass useful information buried in all the rest of the unuseful noise. This is already a problem in some cars where you can't tell if emergency vehicles are nearby/incoming or hear other drivers horn signals. Sometimes you want to ignore this but sometimes it's quite useful.
[1] https://journals.aps.org/prb/abstract/10.1103/PhysRevB.99.02...
Also, where's the STL if I want to try this myself??
Journalists: Acoustic metamaterial blocks all sound. Soundproof yet transparent walls. Cubicles will never be the same.
https://www.eurekalert.org/pub_releases/2019-03/bu-brd030619...
So in this case, if you have a bone to pick, it's not with the journalist.
That's not true. For example, The Fast Company article says "they could be stacked to build soundproof yet transprent walls. Cubicles will never be the same." The press release doesn't include that. This makes sense because it ties in to the emotionally charged reference to "your coworkers" in the title, which is not a trick that the press release pulls.
More significantly, the Fast Company article is written in a cloying hyperbolic style while the press release is pretty neutral. And the titles are beyond comparison, which is probably the most significant thing because titles have the greatest influence on discussion. Many readers have developed allergic reactions to titles like "Scientists have discovered a shape that blocks all sound–even your co-workers", which insult the intelligence so badly.
What's interesting is how the journalistic outlet has to be so much more exaggerated and use so many more tricks even than a press release. Presumably this reflects the economics of media vs. that of universities.
This really depends on the media outlet. Some, like Fast Company are full of uncritical puff pieces about the industry they cover, others not so much.
Economics certainly play a role, however -- from media being soft on their advertisers to industry execs writing for, editing, owning, or having input on hiring/firing decisions to certain media outlets pandering to the lowest common denominator and deliberately writing the most hyperbolic, sensationalistic articles to be popular with readers fond of that sort of fare and outcompete other media that aren't quite as sensationalitic. It's a winning formula, as can be witnessed by the widespread success of tabloids.
Not all media is like this, though.
> Ghaffarivardavagh and Zhang also point to the unsightliness of the sound barriers used today to reduce noise pollution from traffic and see room for an aesthetic upgrade. "Our structure is super lightweight, open, and beautiful. Each piece could be used as a tile or brick to scale up and build a sound-canceling, permeable wall," they say.
...
> "When we want to create a wall, we will go to a hexagonal shape" that can fit together like an open-air honeycomb structure.
> Such walls could help contain many types of noises. Even those from the intense vibrations of an MRI machine, Zhang says.
Nothing there suggests that the journalists were indulging in hyperbole, although they were clearly being light hearted. However, the comment to which I originally replied seemed to be indulging in hypobole.
Your quotes don't mention anything about office noise, cubicles, or coworkers. Why would they add those in? Presumably to make the content more sensational, since that's the effect it has.
"Boston University mechanical engineers create synthetic, sound-silencing structure that blocks 94 percent of sounds"
94% seams to be a lot, but it is far from "canceling" the sound. It's only a -20dB reduction that transform a very loud sound to a loud sound, not to an inaudible sound.
(Also, it is only useful for a narrow interval of frequencies.)