Yesterday I bought a FiiO HS2 - a source switcher. And now I can not hear a difference between FiiO X7, iPhone 5s, Centrance Mini-M8. So what is the best way to compare? Run simultaneously on each one. Or one of them with 1-3-5sec delay from other? Or set 1 track to 3-5 times repeat and then...

How to normalize volume for DAP which does not support Replaygain?

Hi! I need urgently know what is the best solution for portable sound for my HD650 and Dunu Titan. iPhone 5S + Oppo HA-2 or FiiO X5-II? Both I can use as DAC for PC. But FiiO has a more storage. Thanks!   p.s. Also I have a matrix m-strage HPA (amp) and I can use at at home with one of this...