Sony's NW-ZX100 high-resolution music player is a looker, its sleek chassis and large display have a luxury feel. Before we go any further I hope anyone considering a player like the NW-ZX100 ($700, £500, AU$799) already owns at least one set of high-end headphones. If you don't, first invest in a really decent set of 'phones, only then will you fully appreciate what the NW-ZX100 does for the sound of your music.
This player boasts 128GB of built-in storage, and a microSD card slot for additional storage capability for AAC, AIFF, DSD, FLAC, HE-AAC, MP3 and WMA files, with up to 192 kHz/24 bit PCM and 2.8M/5.6M DSD resolution files (during playback DSD files are converted to PCM). The NW-ZX100 also offers wireless Bluetooth operation.
The NW-ZX100's all-metal body feels rather substantial, so I was surprised to see it weighs just 5 ounces (145 grams) and measures 2.1 by 4.7 by 0.6 inches (54 by 120 by 15mm). The 3-inch (76mm) screen isn't a touch screen, all the controls are physical buttons, which I prefer. Included with the NW-ZX100 is a set of Sony MDR-NW750N in-ear headphones. The player has a special setting that optimizes the sound for the MDR-NW750Ns.
Listening with and without the optimization I'm not convinced the setting changes the sound for the better, and the same could be said for the NW-ZX100's other sound tailoring effects such as "Clear Voice," "S-Master," "DSEE," but the "Dynamic Normalizer" did a good job minimizing volume differences from tune to tune, and the Equalizer might be useful for tweaking the sound to taste. As for the MDR-NW750N headphones they're fine, but can't hold a candle next to any of the other headphones I used during the course of this review.
The NW-ZX100 doesn't have enough oomph to play my high-impedance (150 ohm) Sennheiser HD 700 or (600 ohm) Beyerdynamic DT 880 Pro headphones at high volume. At more moderate volume both headphones sounded wonderfully balanced and clear. Most low impedance, under-100 ohm headphones played pretty loud.
As for play time the NW-ZX100's battery holds enough charge for up to 70 hours of MP3 playback, or up to 45 hours of FLAC playback, that's a whole lot longer than most players I've tried.
During comparisons with my Astell & Kern Jr high-res music player it didn't take long to hear the NW ZX100 sounded richer and fuller-bodied. I listened with Audeze EL-8 and AudioQuest NightHawk full-size headphones, and heard similar differences between the two players with my Jerry Harvey Audio JH13 in-ear headphones, the NW-ZX100's sound was consistently more satisfying than the Jr's. There's a sure-footed solidity to the presentation, so instruments and vocals sound more life-like with the NW-ZX100. That one also trumped the Astell & Kern Jr in resolving the quieter details of recordings, like the way a singer phrases the lyrics, the Jr glossed over those details. High-resolution files had slightly better transparency than standard res files.
I also compared the NW-ZX100 with Sony's skinnier and smaller NWZ-A17 ($300, £170) high-res player. The NW-ZX100 sounds richer, more detailed and clear, the NWZ-A17 squashes and flattens the sound. Once you hear the NW-ZX100 you'd never want to settle for the NWZ-A17.
Summing up, I found a lot to like about the NW-ZX100, it's a sweet design that'll bring out the best in high-end headphones.