mtrot,
I added a bit about earphones because you seem to like yours and millercarbon nicely explained what could be causing the difference you notice.
You seem to have decent home equipment but have you considered a possibility that you overall actually prefer the sound coming from phone through the earphones? These days, many people do. Many chase "perfect sound" while they could be enjoying more by accepting the fact that they like "imperfections". At the same time, some people simply prefer the sound through headphones. Chasing speakers to sound like headphones may not be that successful. They are inherently different.
I added a bit about earphones because you seem to like yours and millercarbon nicely explained what could be causing the difference you notice.
You seem to have decent home equipment but have you considered a possibility that you overall actually prefer the sound coming from phone through the earphones? These days, many people do. Many chase "perfect sound" while they could be enjoying more by accepting the fact that they like "imperfections". At the same time, some people simply prefer the sound through headphones. Chasing speakers to sound like headphones may not be that successful. They are inherently different.

