Actually my father in-law used to design loudspeaker systems that canceled certain frequencies put out by power plants at different heights along exhaust stacks
I assume the trick is knowing or calculating how far you are from the source your timing to block, and having speakers that are broadcasting away from the source.
What works in one dimensional ear canal doesn’t work in three dimensional open space.
While we have noise cancelling headphones, have you ever heard of noise cancelling speakers?
Actually my father in-law used to design loudspeaker systems that canceled certain frequencies put out by power plants at different heights along exhaust stacks
I assume the trick is knowing or calculating how far you are from the source your timing to block, and having speakers that are broadcasting away from the source.