I think it's a certainty that ear shape and insertion depth mean different experiences, especially with BA phones that need, at least in my experience, long tips and deep insertion for me to get the full benefit. I know some folks are happy with the Ety sound using the black foam olives or short Complys, but to me, it's either the triple flanges or the UM56 customs I own (and I now use them almost exclusively with any Etys, be it the ER4S/P or the MC5s when I had them). Funny, but I also just ordered the HF2s (for a trial from Amazon, which is selling them for $111), and also am interested in the MC3 or HF3s, not sure. I want a pair to use with my iPod Touch, for skip track/pause/volume.
Anyway, I don't have large ear canals, but I do believe ear canal dimensions/shape greatly effect the Ety bass response results. What else can it be with such differing views? How many times do you see people post on Amazon, CNET or here that they get little or no bass from certain IEMs, but others hear plenty of acceptable bass. Of course, preferences play a role too, but in the end, it's a combo of insertion/tip and ear canal configuration, the latter of which no one can change (unless of course they buy custom tips).
Oh, and you mention "some recordings," and I also believe that's a critical factor. I can be listening to a track using the Etys and even though I like them, the bass sounds somewhat weak. Then, a well-mixed track comes on (for example, Buena, from Morphine's Cure for Pain CD, or the previously unreleased version of Diamonds on the Soles of Her Shoes from Paul Simon's Graceland CD - this one is especially amazing with the Etys), and voila, the bass line blows me away. There has to be a reason for it. It can't be the Etys only work for certain tracks. Even the vauted bass-testing track, Hotel California from the Eagles Hell Freezes Over CD, rumbles with plenty of bass via the Etys (this is with the custom sleeves, on the Touch, via the T3/LOD, no gain switches on).
It's got to be the tracks. Maybe some IEMs, mainly dynamics, cover up those sorts of mastering issues with extra doses of bass. Not sure. But I do notice the variance in bass detail and punch with Etys, depending on tracks. Same with the DBAs I own (similar sound sig).
