Re: King of Isolation: Remote Audio HN-7506 or UltraPhones?
There are a few things that come into play re iso phones:
db reduction claims are typically skewed for the best result. Even UltraPhones - my go-to phones for over 10 years - pick the ideal frequency for their -29db spec.
I haven't found any phones or in-ears that let you "not hear a thing", there will always be a little sound that comes through. I will say that with my -29db phones, I sit at my kit, play it pretty hard, and still have to put drums in the mix to really hear what I'm playing, so they accomplish what I need, and undoubtedly what you're looking for in terms of having the most control over the mix.
You do need to consider sound quality at least on a par with the isolation. You're going to rely on the drivers, so they'd better sound great!
And most importantly, isolation depends on a good seal around your ears. If you've got short hair, buzz cut, or shaved is ideal, you'll get the ultimate isolation any phones can deliver. But any amount of hair that hampers that seal, will reduce isolation and let outside sound in. I'm not suggesting you cut your hair just for that, but it is a consideration. My hair is short, and I buzz cut when I tour so my isolation is excellent (and I also don't have "bunk head" when I wake up!)
Hope that helps! BTW, I had tried the Extreme Isolation phones, and thought the isolation was good, but the sound was not. Got rid of those phones immediately! Also not a fan of the MetroPhones (are they still around?) or Vic Firth phones (although I love their sticks and salt & pepper mills!)