Yeah the SS-100 is like that, stock, but not so much huge in the bass as it is just, low quality. The lesser cup space compressing the damping is likely what causes that.My RP18 appears to be a unique case. I bet once Tyll measures it the distortion plot will be absolutely through the roof in the upper midrange. However, I did love it with the TH600 pads, so I'm gonna give it another go. That's why I repurchased my specific pair.