@FiiO, just wondering if there are any plans for storing multiple user created eq profiles. Haven't played with viper effects at all, so maybe my answer is in there. I do use the default eq, accessed through the playing songs options menu. I have a few headphones that I make just a few dB adjustments in a few spots through out the range, but would love to store the settings so I can switch a little easier between phones. I prefer not to eq at all, which works well on some of my gear, but I have 400i's that need treble hump taming to really shine and some mid-range iem's I have need just a few db added down low and on lower treble freqs to shine. All achievable with this player, but not easy to switch around. Last settings stick in the eq, so on/off works if I happen to have a set that doesn't need eq in the rotation with the set the eq is configured for, but that's just not always the case.