Yeah, squishing tf out of the tape for a while ahead of inserting it or using something less compressible like @spoony 's felt, your plastic idea, or a sliced-up eartip stem, makes the first listen more representative of the long-term behavior. While I like the treble timbre on the (modded) HiFiWalkers better, I concur with you about the bass and mids on these. The bass once reduced to a reasonable level still extends down low and does it right. I haven't tried these out of anything more ambitious than my phone and a DragonFly, but they've become my go-tos for the daily commute. Edit: Also, I think there might be something in the suggestions of an audible break-in effect with these. If my aural memory is reliable and it's not expectation bias from being aware of the rumors, the mids seemed smootherer after a few weeks of use.