@freemo @garyackerman If you look under the hood of your vehicle there are likely resonance chambers in the air intake system. While the resonance chamber serves somewhat of a different purpose, they are echo chambers for certain wavelengths. The exhaust system on a vehicle also has resonance chambers.

Echo chambers aren't just extant but often modeled to target the wavelengths of sound that reaches the ears. Echo chambers are very real and many of us have likely been indoctrinated in special echo chambers so that we can do the same.

It's preposterous to deny the existence of echo chambers and furthermore I probably missed the point of the statement.