[TimeSnow]

If your solution is to use different headphones for mixing the sound, am I going to need to buy another pair of headphones for mixing the mid-range?
If so, then which ones do you recommend me?
Thanks.

(Maybe for first headphones its not the best option the K712)

I think he was trying to say that the K712 should be fine for midrange, and if they don't sound that way it might not be the headphones, but the DAC/Amp that's causing the midrange issues.