I didn't think you were thinking that. Just makes it REALLY hard to talk about neutral bass (or not)
Human hearing or the way we perceive sound is quite interesting, over time you can get accustomed to almost any type of sound. That means bass light / neutral / bass heavy. Quite often if you don't have proper reference point it can be hard to tell what is actually neutral or what is not. Its possible your "memory" is set on bass light sound.
Also its always possible some people are just more sensitive to some frequency like Bass or Treble.
I think this is a very good point also, I would have to lean towards what you mentioned, that my bass "memory" is set on light.
So yes. As far as headphones go, the HP150 are fairly neutral close to neutral. How close? I'm not sure anyone can tell you with certainty, except maybe an audio mixing engineer who works with audio all day long.
I get that, and it is really very helpful to get an opinion from someone with different, and more, experience, so I really appreciate all the replies here, it has been very helpful!