LogFAQs > #973706569

Custom iems prob the most effective at blocking outside noise. Provides Deeper insertion than regular earbuds and the shape of the nozzle and shell will fit perfectly into the ear . So they provide a 100% seal . You can see some artists wear them while on stage at concerts . I remember seeing a pic of Ariana Grande wearing a pair of custom iems that look similar to the 64audio U12T

Then there are the universal iems which are still great at blocking out noise. I find the deeper inserting ones to be at least on par with my wh1000xm3 (noise canceling over ear headphone). Ofc I don't find universal iems to be as comfortable to wear as a lightweight headphone. my ear canal actually feels a bit sore after using them for 3+ hours and I use small sized tips (I've tried silicone and the foamies).