But can you insert the foam tip as fast as the custom? I don't think so . I take mine in and out all the time when I need to communicate and actually listen to the ambiance. I won't have time to compress the foamy tip, put it back to my ear and wait for it to get a correct seal. By then half of the song are already played..
And the Ety.. it hurts, I hate triple flange, but maybe its only me .
Westone's UM Series IEMs (UM1, UM2 & UM3X), unlike the W Series, (W1, W2, W3 & W4) are musicians' monitors - now both UM2 & UM3X also come with detachable cables - and they've been used on stage, too, for quite a while, and though isolation isn't as good as my custom ES3X, it's actually not that far from it. BUT, some people have reported similar levels of isolation using Comply/Foam tips (which I personally don't like). It's also been reported several times that Etymotic IEMs provide even more isolation that customs.