Let’s think about what is going on. Let’s say there is a monotone frequency at constant noise power in a plane wave. Now ANC is a point source of the same frequ

Let’s think about what is going on. Let’s say there is a monotone frequency at constant noise power in a plane wave. Now ANC is a point source of the same frequency. It’s only phase matched on one axis of propagation. Then there is a phase shift in the outside tone and a feedback loop to match the amplifier to the incoming tone. Electronics are fast, but the coil inductance is large, both at the mic and the speaker, so you will get some point of inversion in the match, which looks like a delta function in the interference pattern. A really great-sounding ANC will correct very quickly, which means a very high-frequency discrepancy. Maybe that makes it worse. Maybe high-frequencies that we can’t hear are the problem. Consider also that audio engineering treats the world as a mixture of pressure oscillations. If you look at the world as a sum of pressure delta functions, you would never attempt ANC. It’s easy to phase lock and destructively interfere with a frequency. It’s impossible to do the same with a delta function. The real world maybe a mixture of both, but not easily separable, and to some extent I think the brain is already pretty good at ignoring constant frequencies, while the delta functions drive us mad. Think about a bird versus a hammer, a cello versus a ratchet. My favorite setup is earplugs with over-ear headphones. I think audio circuitry gets things wrong and overdrives the high frequencies sometimes, so the ear plugs help filter it out. The worst for me was the bone conduction headphones - serious problems from those. And one more thing, if you always listen to music, try listening to nature for a bit, either in the real world, or through some very high-quality speakers. I don’t think the Pros are quite good enough for this.