The war of: Can you mix in headphones has been long over.
CONCLUSION , YES YOU CAN.
You cannot mix in just any headphones though. If you don't have a treated room there are headphones that will act as a treated room. I have been using the Sennheiser HD 600, and have been mixing in headphones since 2004. My ear is trained, plus l understand the variable of ear fatigue.
You have to get the right headphones and they will cost more than the average headphones. Your headphones should be balanced with the highs, mids and lows. If one is higher than the other you should not use them to mix only for your llistening pleasure. They should be open back and not closed back noise canceling headphone.
Headphones have advanced to where you can hear left and right and 360 degrees in the stereo field. The direct sound is isolated in headphones and not on monitors. Amateur beat makers who mix on monitors don't have knowledge how to set their monitors and how to set themselves in the "SWEET SPOT". They don't have the knowledge of cutting out frequencies nor gain staging.
In the sweet spot your monitors should be ear level, your monitors should be turned in at an angle where you're sitting in the middle and you turn each one where you can't see the sides of either monitor. (Example below). In headphones you don't have to worry about that, with the right headphones you'll feel as though you're in a treated room.
The sound emanating from each speaker blends together a little bit in the air. This phenomenon is called crossfeed. Putting you in the sweet spot or what is known as CROSSFEED. There are some interesting plugins that can simulate the effect of crossfeed in your DAW, Just be aware of your panning and the width of your sources in the stereo field and you won’t have a problem, don’t be afraid to pan wide! I use the Binaural effect in S1v4 and a few others that are really dope.
This the main reason for me going entirely INSIDE THE BOX. Being ITB elinates noise floor. Humming from having many pieces of gear plugged up and hissing. This cause you to bring levels higher to bypass the noise floor. I don't have to do that. Two factors come to mind, knowledge of mixing and practicing over and over! When l take my mixes to the major studio it sounds amazing, some people that are there ask where did l mix my track l tell them in my house and headphones. They look at me weird. I still reference my music in a car or my monitors to see if anything is outta wack.
Having a higher ohm's value can boost your headphones and make your sounds, sound fuller.
thank you