As with the cheapo, so too with the custom

Breathing lessons: the peculiar pleasure of earplugs - "I could hear people speaking, I could hear sounds, but it all took place at a remove. And yet I did not feel farther away from everything. I moved through the streets as though in a dream, but, as with a dream, somehow more attentive and aware than usual. Up to that point the purpose of earplugs was to keep things out. Now I perceived a new dimension to earplugs—to keep things in." [Slate]

The effect only gets stronger when you graduate to the custom kind.