Oh, I see, I misunderstood it, sorry... I mean judging from your recording, I suspected that it's the amount of low frequency content that is the culprit, as in both of your recordings the low end seems lacking to my ear...The filter in the last sample I posted was a high cut filter; it filters out the high end. If excessive high frequency content were the culprit, the effect you're referring to should've been much more prominent in that sample, in my opinion, because I basically removed all of the high end, but the effect still sounded less prominent than what I'm hearing in your sample.
(I am currently away, I will need to verify this later today)