First of all, let me clarify that I am neither an expert in acoustics, nor do I have a professional involvement in music, so I don't know about mid-range, high, and low... but I have had them for 2.5 years and I have used them daily, so I will give you a real-life experience!
I got them just in time before the first lockdown and they kept me mentally balanced in a 40 sqm house with two kids running around! Life saver! I could hear the loud arguments, the unnecessary nagging, but I didn't have to intervene!
Noise Cancelling: It cuts off the strong north wind and the crashing waves on the rocks, but you also have the option to deactivate it, which gives you extra battery life, and you can hear the gentle waves on the beach while listening to a voice in an audiobook without one disturbing the other. There is also an intermediate button that I haven't touched or remember what it does.
Sound Quality: I like to listen to music as if it's being played right next to me, to distinguish each instrument in classical music, to hear Vissi's breath and the breaking of her voice in "Sudden Love," and to feel like I'm at the Buddha Bar while defrosting chicken with a hairdryer, with the drums staying in place during headbanging, and feeling the deep bass in extreme Norwegian metal. Since I can't buy a super-duper sound system for my house and annoy everyone with my wide range of music, these are the only ones that have met my high standards for listening.
Customization/Presets: You can adjust a custom mode in the app with deeper bass (I know, irrelevant, but I'm only human, I want to feel my heart pounding), and you can switch by pressing a button on the headphone from "effect mode-" -club (which hits your chest), -movie (where you can hear the spoon hitting the actress's plate), -speech for those endless zoom calls or audiobooks: crystal-clear voice, zero noise, -director (which is the custom mode I mentioned earlier), and -off, which puts it in its neutral state. They have all perfectly met my needs.
Connectivity/Intuitive Use: They automatically connect to two devices simultaneously, so you can listen to a course on your laptop while receiving a call on your phone, and you can answer with a tap on the headphone. You can comfortably play electric guitar and scream at the same time, and if you think you heard a doorbell in the background, you lift the right headphone from your ear and the music automatically stops! As soon as you put it back on your ear, it resumes where it left off. By gently swiping your finger forward or backward on the headphone, you can change songs and adjust the volume up and down (which could be stronger on one side, but it might save your life because you'll hear the horn as if it's lost in space, and if you walk gracefully to the beat!).
Overall, being able to listen to music on the go, come home and have them wirelessly connected to the laptop ready for work, is a great feat! The fact that you can turn off all the Bluetooth (shouldn't the plural be blueteeth?) and play with just the cable is also an option! I want options!
Battery: I charge them once every two weeks, approximately with 5-6 hours of daily use, constantly on Bluetooth and noise cancelling. The battery performance hasn't declined at all after 2.5 years of daily use!
Also, a strong point for me is that when the battery runs out, they are the only ones that you plug in with a cable to your laptop and another cable to their charger and continue to use them while they charge.
Temperature/comfort: In the summer, during the scorching heat, you won't go outside wearing them easily, yes they get warm, but who goes outside in the middle of the day in the summer heat to begin with? In the evening, they are manageable, especially on the island where it's always cool... In autumn-winter-spring, I don't go anywhere without them! It has become a criterion for my bag; if it doesn't fit them, the bag is useless!
Another reason I bought them was because my ears would freeze and hurt in the winter while I walked on the field while my little one was practicing, my ears no longer hurt, I even run with them, they don't ring, they don't weigh me down. I would like a slightly thicker cushion at the top of the head, but every head is different, you can't call them thin... Also, during calls and on the road, they give incredible style and keep the hair in place (vain much?)
What else haven't I mentioned? If you are a bit introverted, all over-ear headphones prevent strangers from talking to you on the street... The only negative thing I can find in these, if I really push it (because even if I sold them, I would buy them again), is the wear and tear of the faux leather in two and a half years (maybe it's because I have their case abandoned in a drawer and it has become a cable storage nest), but I will look for replacement cushions and headbands because the sound is still unbeatable!
Durability: unbelievable! Constantly squeezed in backpacks, sandwiched between pens and laptops, wrapped in final exams (they fold and "break" both headphones without any damage), thrown in bags with keys, phones, water bottles on top of them, they haven't made a sound!
And something I discovered and I doubt if the manufacturer had consciously intended this, is that when I have them connected to my laptop with the cable and I have turned the headphone off (they open and close with a twist of the headphone), and I forget and still play music, they function like a mild and discreet speaker! (No comparison to a real speaker, but sound comes out normally!)
That's it, and the next ones and the ones after that, and gifts for sweet sixteen children when the time comes, will only be Sennheiser!
The most expensive and best gift I have ever given myself, worth every cent!