I'll take two...

[DaleVO]

New ‘sound absorption’ method cancels out 99.7 percent of all sound
Read more: Near total silence possible with new sound removal technology | Digital Trends

 

[JimmyS1969]

And it is how thick? How heavy? How expensive?

Where do I buy it! I'll take 8...

 

[mjbphotos]

Its a double resonator system, so would only cancel out one (series) of frequencies.

 

[DaleVO]

Its a double resonator system, so would only cancel out one (series) of frequencies.

MJ,
I saw that. The article triggered my inner-geek, to find out more information on Physics.org Researchers achieve near-perfect absorption of sounds waves

They can cancel a series of freqs now. Maybe their next step is to create a parametric version. Imagine the possibilities.... hmmmmmm
Dale