This or having perfectly Titan-matching ears.
As in my ears, the tape-modded T3 sounds just like the stock T3
in my ears.
Some tape-modded measurements of the T3 and T5 I posted a couple pages back:
http://www.head-fi.org/t/744083/dunu-titan-series-1-1es-3-5-ti-coated-diaphragm-half-in-ear-earphones/2550#post_12202820
One line shows a more or less "free-air" performance as if there was no ear close to the vent (freely sitting in the measurement coupler with literally nothing around and behind it), the other shows the FR with completely blocked vents.
Depending on how the IEMs sit in one's ears, the sound signature one is perceiving will be somewhere in-between both lines. In my ears and Nik's (
@nmatheis), there was no lack of bass at all with the T3.
Just recently, I tried to flip the Titan 3 upside down so that the vent was pretty much freely sitting in my ears (the tip was perfectly sealing though, so the ensuing result was not seal-related). With that pretty much free vent, I suddenly faced the thin, upper-mid centric sound without bass emphasis some were describing.
Guess I am lucky about the way may ears's shape and the Titans' vents harmonise together, as especially the T3 sounds very even, balanced and correct in the mids the regular way I'm wearing it. For those who are facing way too thin, sibilant-prone upper mids and a lack of bass with the T3, I suggest either to go to a plastic surgeon to transform your ears' shape into mine or to try the tape mod.