I've been looking at getting a pair of these for months. The reviews on them are all over the place, some reviewers really like them, others not so much. So, when I found a deal on them where they were 35% off, decided to try them to see if they would work out. They are going to be primarily used with Astell+Kern KANN, with occasional use with a McIntosh D150.
After listening to them for several days, I'm happy to report that they are very enjoyable headphones for use with all types of music. Although they are closed, they present the music very close to an open headphone type. The frequency response is among the widest on the market, and the overall clarity is remarkable. While they are not as accurate as some other reference headphones in the same price range, they are damn enjoyable. I'm very impressed with just how big (and right) symphonic pieces sound with these. The listener can hear the orchestra very clearly, with the proper proportional volume of the various instruments. Jazz/Rock music has lots of dynamics and punch with these. I found the bass to be full sounding, very musical, with good definition. Mid-range is very clear and natural sounding, and the treble is pristine, but not overly hot. The treble pretension provides a good balance between clarity and detail.
Instruments such as piano and strings sound very natural sounding.
Comparing the Z7's to a couple of IEM's I tried provided some interesting contrasts. The IEM's present some aspects of reproduction with what some would refer to as more accuracy. However, the Z7's (to me) actually present complex music with a better sense of octave to octave balance. This is especially noticeable with heavy symphonic music. Overall, when at home, the Z7's provide a more enjoyable listening session.
In order to properly drive these, the KANN needs to be set at the HIGH output to get the best from them. If using with a DAP (other than the KANN), a separate amp would be best with the Z7's, but it isn't absolutely necessary.
Lastly, I'm impressed with the build quality of Z7's. for big headphones, they are both light and comfortable. The headphone body is made of metal, and the cables are replaceable. They are also made in Japan, and it's obvious that there is a high level of quality control.
In summary, the Sony MDR-Z7 is a quality headphone, worthy of a recommended auditioning. They perform well with all types of music, and can be worn for hours comfortably. With headphones, personal preferences are more of an issue than with just about any other piece of audio gear, but I think most folks would enjoy these.