I’m going to start making posts about IEM’s here on my blog instead of various forums. I am in total control here. I can say anything I want. There are no mods, no advertising or marketing to limit free thought. I’m probably never going to actually fully review these, or anything in this ‘First Impressions’ “series”, but these are going to be a review after an initial 24 hour listening impression. This isn’t 24 hours of continuous listening, this is just 24 hours of trying to avoid co-wokers, sound isolation & entertainment on my bus/train commute, and normal at home listening. I’m also not going to nitpick on things like ‘timbre’ & ‘speed’. I ‘burned them in’ for 30 whole minutes, and my sources are my Xiaomi Mi A2 Lite (Snapdragon 625),¬† XPS 13, and TRN BT10’s using the aptX codec, probably a similar setup to any other person buying $38 IEM’s would use. You’re buying $38 Chinese IEM’s that people are comparing to Campfire Audio Andromeda’s, don’t you think multi hundred billion dollar corporations like Qualcomm with world class engineers have audio circuits pretty figured out? Media will be 320k Spotify, probably 128/96Kbps soundcloud, maybe a couple of FLAC tracks. Cables will be whatever I have laying around, since cables don’t matter. All of this is subjective, please don’t just buy this because I said so. Research reviews, figure out if they align, then buy based on what you think your preferences might be.

Bass. Cannons. At first. Seriously, these go low. ‘Drake – Free Smoke’ is intense and moves a lot of air. It’s accurate and I don’t see any obvious flaws. It sounds good, but the bass is slightly overpowering so far. Listening to the 320k download of Soulection Show #388, bass & mid bass are very present throughout the whole episode, again slightly overpowering. The rest of the sound signature is still fairly neutral, perfectly present, and distinctly separate from the heavy lows. I have not yet tried any of the reportedly bass head ZS3 or ZS4, but among the KZ IEM’s I own, these are the most bass heavy in their lineup. Even the Tennmak Piano’s can’t perform like this. After a while, you do get used to it and it does start becoming less present, but it’s still pretty heavy on lows. It’s fairly heavy in other genre’s as well, but I feel like the ability to extend so low and not fall off, only adds a positive element to the sound signature; a more full sound. I ran a tone generator and I can hear an audible frequency down to 18Hz, but the background ambient noise was oscillating. I am not a sound engineer or audiologist, but I’m not sure if that’s something to worry about regarding the sound design, or if it’s perfectly normal. Usually bass & sub bass fall to the noise floor when I’m on the light rail during my commute using IEM’s or headphones, but not with these. I have a feeling a lot of people are going to find the bass of these overpowering. Its almost in a sense, a reverse of the ZS6. I’m personally fine with it, but if you think the AS10 is too much, this is taking the AS10 mid bass and adding in a ~18-60hz DD at the same level as that mid bass. At the same time, it’s possible this may bring new people into KZ. The extent to how low these can go, and how much more full that makes the overall sound may be something new to the KZ line. The ZS7’s absolutely slap.

Mid bass is just as present as the AS10’s. Fairly overpowering at first but you get used to it. It’s very similar to the AS10 in that it has a lot of texture and it gives the sound signature that extra punch & fullness that older KZ models didn’t really have. I don’t really have much music where a detailed mid bass matters, so I’m not going to be of much use here. Compared to the ZSN’s, the bassline in ‘Jorja Smith – Lost & Found’ is much more textured and precise. It really feels like you’re sitting next to the cabinet. Kick drums sound detailed and airy. The BA is definitely better at mid bass than the DD in the ZSN.

Mids are definitely some of the best in KZ’s lineup. Vocals both male & female are forward with no sibilance. Doing an A/B of the ZSN’s and ZS7’s, the ZSN’s are very sibilant on vocals comparatively. Not only is there no sibilance on the ZS7’s vocals, they are more forward and neutral. Along with the mids, you also get the mid bass and deeper sub bass to work together and make awesome goosebumps creating microphone pops and really add to a full range of microphone frequency response.

Highs are fairly rolled off similar to my AS10’s (I know others have said they’re bright!) but definitely extend high enough. They can sparkle, but it’s very controlled. I notice more of a response from cymbals with the ZS7’s, as in they can produce a more accurate sound signature than probably all of the prior KZ’s I own. I wish the highs extended further and I wish the ZS7 was a little more bright overall, but it’s good enough in its current configuration. I wish it had some of the ZS6’s brightness, but it’s not remotely close.

Soundstage & Imaging are on par with the ZS10’s, probably a bit more spacious of a sound field with more stereo separation, but not by much. Quite wide and airy. I haven’t had anything wider than this except for the ZS6’s that I lost one side of. Impressive, but doesn’t blow my mind more than other ‘top’ IEM’s I own. The recent AS10 and ZSN are extremely narrow compared to the ZS7 and ZS10.

Left: KZ ZS7 – Right: KZ ZS6
Top: KZ ZS7 – Bottom: KZ ZS6

Compared to the ZS6, their size is indistinguishable and the only noticeable changes are with the angles of the outer grilles. Compared to other recent KZ offerings:

Left to Right: ZS7, ZS6, ZS5v1, ZSN, AS10, ZS10

Comfort is on par with the ZS6’s & ZS5’s. It doesn’t bother my ears, but the edges may bother some. They do stick out of my ears by a few millimeters, but it’s not a big issue. I would prefer this in the AS10 shell as it is one of the most comfortable & well sealing of KZ’s IEM’s in my opinion. The nozzles and included starline tips seem very sensitive to the position you have them in your ear, so I might recommend trying alternate tips. I found spinfits to work the best on the ZS6’s, but I will need to order another pair to test them on the ZS7’s. There is now a lip on the nozzle so I don’t have to pick abandoned ear tips out of my ear with tweezers in the bathroom at work anymore.

Isolation is just mediocre and much less ambient sound is blocked compared to the isolation of the AS10. It’s better than a lot of KZ’s but it lets in some stronger mids & highs that make it sound somewhat open. Its isolation is slightly less of that than the ZSN’s.

For the current going price of around $38-$40, it’s another excellent addition to the KZ family, and something I would recommend to people who want a huge low end and a more full sound. These will likely be my daily drivers over the AS10’s. They’re a perfect upgrade (and cheaper!) to the AS10’s. I expect KZ to release future models based around this, with a more refined sound signature.

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