Loud setting on generally sounds like beats headphones. That super shitty V- curve lol. If you are listening at lower volume then turn up the gain a bit more. Keep in mind where ever the max volume was for you volume before, thats now at waay past clipping levels, so your max volume you can safely go up on the headunit after upping the gains will decrease dramatically. There's tradeoffs to every setting.
Another way you can go about it is lowering the gain on your mids and highs amp so that you have to turn the volume up higher but it'll still be the same listening level you would want.