Passive IEMs are better, ANC is always weaker and more selective. I was once using Etymotic IEM and frantically searched for the source of a loud wind noise that hit my ears upon removing the earphones, only to realize it's just an air conditioner on the ceiling. That don't happen with ANC headphones, partly due to technology and partly for product safety concerns.
Have you compared passive IEMs to Apple's noise cancelling headphones? I compared Apple's products to properly inserted earplugs and Apple's ANC was better for low to medium frequency sound, so I wonder how you arrived at the opposite conclusion when it comes to IEMs
With properly inserted hardcore isolating earphones, and with music playing at low volume(important), I just don’t notice any other sound. Including landline ringing. Perhaps fire alarms too. It’s an auditory anesthesia. Like if I’ve put on a VR goggle, but for my ears.
And that is natural, after all it’s 40dB advertised isolation with ~15dB? sound on top. There’s no way those ANC earphones with small drivers powered from a toothpick batteries and thin rubber cap sealing the ear canal can beat that.
I also have a SONY WF-1000X, and an SE215 for that matter, both with Comply tips. They are nice, but no match against proper Etymotic dead silence.
ANC earphones are not designed with maximum sealing in mind(sometimes intentionally). Doesn't matter how plug and ear canal is tightly fit together, if what is suspended in the middle was a pipe with open ends.
ER4SR is the most classic/standard Etymotic model currently sold, other models complementing in both direction of prices. Perhaps more important than tip selection is correct insertion, or Practice and patience, which is unbelievably the exact wording used in their instruction manuals at least for my ER-6i. It is definitely not the healthiest earphones in the market.
