I can only agree with the other comments. There is no vacuum, but you have to get used to the NC. By the way, they can be calibrated to your own ear at the touch of a button. They are the best headphones I have ever had.

The first time I put on the MDR 1000X, I also had a slight vacuum feeling, as if the ear cups were sucking on my head. However, I got used to it immediately. I think it's not so much the NC, but more the shape of the ear cups, which fit very tightly (but still softly!) to the head.

Physically, there is certainly no vacuum, but sometimes you get a feeling of pressure fluctuations on your ears. This is due to the NC and the sensitivity of the person. It is certainly independent of the model. I don't know which model I have, but I really only have this feeling of pressure when we cross another train on the train. Everything is silent, but the pressure wave is slightly amplified by the NC.