Hi Costy, I'm running them on high gain and with balanced cable, I think balanced gives an improvement to the sound over single ended, plus I think high gain gives a slightly fuller sound, but only by small amounts. As for them being brighter on high gain, again by a small amount, but that could be down to me being less sensitive to high fr, plus the music/recordings you listen to, and the rest of your system, can have an affect, plus also, it might take a little while to get used to high gain if you haven't used it before, it may sound like stating the obvious but have you tried just turning the volume down a bit, I find, depending on the recording that once I get past a certain volume, on a given recording it can then get harsh, but just that that slight turn down is sometimes all that is needed, and yes having flu, I'm sure will mess with you hearing too.