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Pinholes and Plastic Wrap Make Solid Walls "Transparent" To Sound
First time accepted submitter benonemusic writes "Researchers have devised a means of making sound transmit easily through rigid surfaces, including walls. The process relies on creating small holes on a wall, and covering them on one side with a thin covering made from plastic wrap."
If it is mono-directional it has application as sound proofing.
If it is bidirectional then the listener can be heard doing what listeners do as well as the "target".
If regions could be made "transparent" then 3D audio precision might be possible.
Interesting.... but I am not going to dig holes in my walls.
Truth is stranger than fiction, but it is because Fiction is obliged to stick to possibilities; Truth isn't. Mark Twain.
Ok, build a bunch of drum heads into a wall and notice they act just like, well, drum heads.
Brilliant. An acoustic diaphragm.
Can't think of a single use for this other than eves dropping where no electronics were allowed.
NSA Jokes, apartment sex jokes, etc. aside this is apparently a potential way to increase the precision of ultrasound scanning for medical diagnosis. As medical imaging is being used extensively to diagnose early cancer (among many other things), advances like this could have really profound effects on healthcare.
The 'walls' were thin sheets of metal - yes - this is an interesting breakthrough, but will not help much for thick walls.
The effect is strongly frequency dependant, and relies on tuned membranes.
It will not work for signals such as voice.
Or at least - it will not work as well as it would for tuned signals.
It is unclear if you can get a useful effect with a large number (say 50) of tuned membranes covering the voice band.
You can perhaps also do interesting novel things with tuning, if this is possible.
You can have a 'transparent' wall - that mutes certain tones - for example if you want to notch out a train whistle that goes past every day.
Audio prisms are another application that springs to mind.
There's also a use in controlled/clean rooms. You can already get some something similar, there called Talk-Throughs (not affiliated, just top google hit).
I am not sure if this technology has a benefit over the existing solution, but it may. Maybe just because it looks cool. There is also a section at the bottom of TFA that gives over uses.
Most Damage is done by people who are AWAKE
Some complementary work done at UT-austin
Instead of a membrane matching the impedence of a "meta-material" made by punching regularly spaces in a wall (kind of like a meta-material drum), the UT-austin work describe holes made with a "meta-material" approach. Basically a hole with some transverse tubes cut a regular intervals to create resonances that change the effective impedance parameters allowing pretty much lossless transmission through the hole (kind of like a meta-material horn).