Apologies for the log post - which I am making longer. I replied to an old thread before realizing that this is probably the best place to ask what I wanted. Thread that I replied to asked comparing the 1770 to the 700 Pro X and the 770 Pro. Here it comes.
I know I am replying to a very old thread, but thinking is better to pick up from an existing thread. I was looking for feedback on people's experience with the 700 Pro X and I found this thread, so I will answer first the OP.
I own all of them. The DT 1770 Pro is to me, very similar to the 770 Pro. Not a bass monster but a very good amount of bass, right out the box. I got the DT 700 Pro X and I expected them to be similar to the DT 770 Pro. To my surprise, NOT AT ALL. Very very flat, IMHO, which is a sound signature I don't enjoy. Before putting them on sale I decided to give them one more chance.
Now, a bit of an intermission. In the past I owned a pair of AKG k550s. Now, more than flat with no bass, well, they sounded, to me, too hyped up in the highs to the point of being painful. Coincidentally, my friend bought an equalizer around the time I was trying to decide whether to keep the k550s or not. So I hauled the k550s to my friend's house and tried them with EQ. To my amazement, they wouldn't budge. No matter what I did on the equalizer, sound did not change!

Up until that point I did not really know that headphones responded differently to EQ. I assumed they all would. K550s were sold.
Which brings me back to the DT 700 Pro X. Even though the 1770 and the 770 Pro are marketed as studio headphones, well, like I said, they are not truly flat. They are, TO MY HEARING, the perfect sweet spot for those of us that favour a little bit more bass.
I don't normally use EQ, but I decided to try equalizing the 700 Pro X in Roon, using their new plugin for headphone eq and my own settings for the parametric eq plugin using Autoeq.app.
Well... in my opinion and conclusion, the 700 Pro X are TRUE studio headphones. Let me explain. To my own logic and intuition, a true studio headphone should be naturally flat but responsive to EQ. In my mind that's what you want if you are recording and/or mastering. You want a signal reproduced with no adornments but you also want the changes you make in the signal chain to be audible.
So that is exactly what the DT 700 Pro X are. Adding different EQ settings, I feel they can approximate both the 1770 and 770 Pro sound signatures. Normally I don't use EQ, so they are not my go to cans for non-Roon listening. But for Roon listening with access to the plugins, I use them quite often, having settled on an eq setting that is kind of adding a bit more high and mid presence to the 1770 (or 770 Pro). My objective was, kind of like a Grado with more bass. Which is a sound signature that is not in my current can selection. So I found them useful that way and was able to keep them.
That said, my question was exactly that - what are your experiences with the 700 Pro X? Do you find my assessment ( flat but very EQ-able) similar to yours? Do you always use them with EQ? Or always without?
thnx!