Thanks for that interesting aspect I never thought of that! I now learned something new
This might be the reason why I prefer the universal iem cause it has that equation out and it uses my own ear canal as path which leads to a more natural perception as I am more habituated to hear sound this way....
I would say now its all the force of the eartips selection to make sure I get the proper sound.
I use 64a stock medium eartips I find its the best way to make sure that I am hearing the frequencies as 64a intended it to work.
I have one huge ask maybe one day 64a can release the silicone eartips with foam inside? Like a hybrid eartips. That helps tremendously on isolation and silicon tips has way better sound precision.