So you've never experienced a difference before on your other players? My DX100 exhibited noticeable differences as well. More so on the newer firmware it was not necessary as it made the sound stage too big, but even more flat IMO. What I like about the EQ Flat on the iRiver is it allows me to turn the volume up higher without getting fatigued while if I use it on EQ off I'll have to listen even lower and thus be a bit bored lol. Strangely enough I felt I am getting more detail in the mids now since EQ is set to flat. For some reason I feel that extra treble is overshadowing some of the micro-detailing in the mids. At least for me it's distracting and taking away from it.
Edited by lee730 - 1/12/13 at 1:10pm