At 143, your eyes might vibrate a little, you can feel your ear drums flexing, it's not all too intense though. At 155, your eyes get blurry bad, it starts to get hard to breathe, and your head feels like someone is sitting on it. The feel varies at different frequencies, I'm just saying I've sat in both on music and that's what I experienced. 143 to 155 may be a small number increase, but a big SPL increase.