When it comes to monitoring it is important to be good with reading and understanding rms and peak levels across the frequency + stereo spectrum, that you can trust. In my opinion that should be the focus because it is your insurance policy against poor monitoring when you are aiming for a pro sound. It is also good to know the relative loudness between their lows, mids and highs, as well as 'lows + mids' vs highs, and lows vs 'mids + highs'. For instance you need to understand what builds up the perception of the low end, is it because of direct velocity in that frequency range, is it building up due to lack of mids for instance, or is it building up due to too little velocity in mids and highs combined... etc... You simply have to understand what's building up the perception in the various frequency ranges.
In general it is difficult to achieve a good sound with a single pair of headphones, but if you can find say 3 good pairs and their individual gain sweet spot, then in combination with A/B you can achieve a pretty decent translation.
I think the Audio Technica M-50x with the short cable are worth a purchase, incredible value for the money, they work with any amp and provide a good reference when you A/B.
In general closed back headphones work better because they tend to produce somewhat more bass and that tends to provide somewhat lighter mixes. A bass heavy mix is the artist's work down the toilet, it is incredibly important to not have too much low end in the mix.
When you mix it can be good to mute the bass and kick first, then bring in a little, in this way you tend to bring in more low end frequencies from the other sound sources and you can fill up the low mids more and brind in more combined warmth, it is also important because the low end can become distracting, you need to be able to focus on getting the mids and highs good first of all. Then when you add the bass and kick you won't have to add as much signal, but to enhance the perception of the lows at those lower velocities you can side chain compress the kick and bass with competing sound sources in the same frequency range. (be gentle/precise) This makes it so that you get a light punch, enough perception of the low end and a bright overall frequency response. Focus that side chain compression only to the frequency range where it is needed. The warmth in the lower mids is very important, it has to shine through without creating an overall muddy sound, try to bring it out towards the side, so that the center stays clear. You are losing warmth if the cutoff is too steep, try to make the cutoff not so steep, but cut it steeply right at the end to remove rumble noise in the low sub frequencies. Try to bring in the bulk of the low end from a stringed sound source other than the bass guitar, and make that stringed sound source pump with the kick drum and snare. I think the best is two different electric rhythm guitars with a big body, one panned L, the other panned R. Organ, piano, pad, acoustic guitar you can fit on the inside of those and then add the vocals and snare panned in between (in terms of width). The cymbals I like to have panned far right and left. The hi-hat I want near the center. Percussion I want outside of the hi-hat. Pedal steel and pad I want at the stereo sweet spot on the inside of the outer edge. I want delays and reverbs very far out, very airy and lush.
I like to start with the mids and highs with the bass muted. When the highs are somewhere near the target , I bring in a little bass and kick, so little that I think it is still too quiet for the final. Now I dial in the mids to near the target levels. Then I finally bring in the low end to near target while keeping an eye on the meters. Then I iterate a little to set the rms and peaks to near my target. Then I start to A/B and engage various monitoring solutions. During this work I do a lot of M S relative balancing and focus a lot on the sound of the S component. I have specific rms and peak level ranges I target across the frequency range for the S component. Having the right frequency response and levels on the S component is incredibly important, that is where much of the perception of a pro sound comes from. You can have a weak noisy signal there or a well gained clear awesome sounding one.
Although I think the monitoring solutions in terms of hardware is very important, I do think the work with monitoring is equally important. I think for instance it is important to bring in the L and R side individually in mono to both ears at the same time to be able to perceive the sound of each side as if it was a stereo mix of its own, especially when the side component is sent that way, because two ears can perceive more and when you apply both ears to each dimension individually, you get better sound on each and the product combines into a superior sound. Similarily, it can be good to mix sound sources that are grouped to be localized to sit at some specific position, with a dedicated monitoring solution for each. This makes it so that these sound sources separate more and you get a better overall sound because the stereo field is not "smeared".
You should be vary careful with headphone monitoring solutions where you have way too little power to drive the headphones. Certain headphones from e.g. Audeze, Sennheiser etc. require a very powerful amp to drive them. It's all about getting "into" the sound and that requires enough amplification. That's also why you have to find the gain sweet spot because you get more into the sound at that gain level, the frequency response is somewhat more flat there and you can perceive more of the stereo image there. In combination with lots of headroom in your hardware it creates a great sound.
I could use the K712 and DT880 for certain things but would rely on other ones such as the M-50x for more heavy duty work.
If any of you know of any headphones that are way way better sounding than the M-50x, please let me know. But be honest.
