Perhaps you will be surprised that the parameters of the SOUND are both a plus and a minus at the same time. I will explain in simple terms, the sound here is absolutely the same as in the previous model. And in the previous model, the sound is incredibly good, both in volume and in balance and volume. There are no obvious distortions (in bass, in treble, in a fierce V-shaped frequency response, and so on). And there is everything that a potential buyer expects from such headphones: powerful (but in moderation) bass, decent detail and generally comfortable sound. It is for this reason that 4 stars and not 5. as I always look forward to improving the sound in each new model, since these headphones are primarily for listening to music, and only then for everything else. For me, this parameter is the most important, more important than those few soft options that are added to them. But in terms of convenience, they have become much better. The previous ones were slightly cramped for the ears, here, due to the additional volume of internal space, they sit much more comfortably. Those with big ears will definitely appreciate it. A sensor has also appeared that is responsible for turning off playback as soon as you remove them. In general, the design and appearance remained unchanged and at first glance it is difficult to distinguish them by comparing them head-on with the 3rd series model. To summarize, I will say this. If you already have headphones of the 3rd series, then I see no reason to run and sell them to buy these, for the rest I will say this: if sound is more important to you, then I advise you to buy Sony WH-1000XM3 headphones, which now cost 10,000 cheaper than these. And those who, in addition to sound, need wider functionality (proximity sensor, simultaneous connection of two devices, improved noise reduction at the macro level, etc.) or if you have big ears, then take the 4th series and get ready to fork out for an additional 10k. Thank you for your attention, all the best✌️