I did find this old article on stereophile which I thought was interesting with some measurement of the effects of different tips.
This story originally appeared at InnerFidelity.com The Trouble with Tips Numerous people have asked me to investigate how ear tips affect the frequency response of in-ear monitors (IEMs). Personally, I've not experienced much change in tone when changing from one tip type to another, but I've...
From what I gather how well say a triple flange works depends on the shape of your inner ear, i.e. whether the end of the tips get squashed by the shape of the inner ear. I don't think that is happening for me, but I can definitely imagine this happening for lots of people.