Originally Posted by dfkt
Both OF and Rockbox have the exact same frequency response - ruler flat, no matter what phones they have to drive. There's no bass boost by default. With "default EQ" I guess you mean "normal EQ"? In the OF that means the EQ is turned off. It might indeed be that Rockbox is a bit quieter than the OF, but that's about the only difference.
Even though the frequency responses are the same regardless of impedance, it just seems that Rockbox handles the voltage output differently to the OF. Cans are driven by power (as well as sound wave frequencies) and even though both the OF & Rockbox may be sending the exact same frequencies to your headphones... the "current/voltage" regulated by the OF is giving the diaphragms in heaphones more juice.
Rockbox is still great software, regardless.