Help me understand this: Using my Ultimate Ears headphones,

[fuzzybabybunny]

When I plug my Ultimate Ears headphones into my Logitech Z-5500 control console, I have to turn the volume knob to around 90% to get decent volume. When I plug these headphones into my little Archos Gmini 220 MP3 player, the volume at 50% is plenty.

Why does my big honking Logitech control console require higher volume levels than my little MP3 player?

 

[eplebnista]

Different power output/impedance?