Hey there fam and welcome to another review. In the labs today is the K7 ZS7 earphone with 1 dynamic and 4 balanced armature drivers per side. It’s got a metal body, big, bold sound, detachable cable and costs less than $50. Interested? Then let’s keep going.
KZ is a brand that I’m sure does not need an intro. But just in case it’s your first time here or you’re new to the in-ears world I’ll do one real quick. KZ (Knowledge Zenith) is like the Walmart of IEMs, the McDonalds of in-ear monitors and a giant among even the many large Chinese earphone manufacturers. They specialize in the mass-production of high price-to-performance earphones and have models to suit just about any preference when it comes to sound signature.
Good build quality
Bold and detailed sound signature
Easy to drive
Upper midrange too forward
Stock cable is not very good
Driver unit: 1DD+4BA hybrid driver unit
Earphone sensitivity: 105dB/mW
Frequency range: 20-40000Hz
Earphone interface: 2Pin Interface
Cable Length: 1.2m±5cm
This sample was provided for the purpose of an honest review. All observations and opinions here are my own based on my personal experience with the product.
Package and Accessories
Anyone who follows this blog or KZ releases will recognize the typical KZ packaging here. The ZS7 comes in a plain black box with a brand logo on the front. Opening the front flap reveals the earphones seated in a soft, black foam insert. Down at the bottom is the now familiar KZ plaque which is mostly useless but I’m sure many people will appreciate it nonetheless.
Beneath the foam are the standard KZ accessories. Let’s break down the contents of the box.
KZ ZS7 earphones
Detachable 2-pin cable
3 pairs of silicone eartips (S, M, L)
User guide, warranty card and QC pass
As usual the accessories are nothing to get excited about, although maybe you should be excited because this is one of the factors that allows KZ to provide such good value IEMs. I was disappointed to see the familiar brown, twisted cable with the devil’s own memory wire and Y-split located halfway to hell. KZ, if you’re reading this please update your default cable!
Build Quality and Design
The KZ ZS7 sports all-metal housings that are similar to the previous ZS6 model. It has 3 angled vents on the faceplate and 3 screws attaching the faceplate to the shell. At the time of writing it seems the ZS7 is only available in 1 colour combination which is blue and black.
The earpieces have a little bit of heft to them without feeling heavy and overall they feel very well built for the price. On the inside of the shell there is a single pinhole-size vent close to the base of the nozzle.
There is a lip on the end of the nozzle which helps to hold the eartips on securely – much better than the method used on the AS10 and AS06. Covering the mouth of the nozzle is the typical metal mesh which prevents earwax and other sediment from penetrating the housings.
Comfort and Noise Isolation
I find the ZS7 to be a lot more comfortable than I was expecting. In pictures it looks quite chunky and angular but in reality the edges are smooth and the shape of the earpieces fit naturally in your ears. I have not problems listening all day with this earphone when it comes to comfort.
Noise isolation is about average for this type of in-ear monitor. Outside noise is partially blocked but once the music is playing you won’t hear much else. For use in transit, on public transport and most everyday environments it will be just fine.
There is a bit of noise leak but it shouldn’t be of any concern unless you’re really blasting your music in a quiet place.
The KZ ZS7 has a V-shaped sound signature that’s big and bold from top to bottom. A solid, enhanced bass, recessed but clear midrange and a smooth, somewhat laid back treble add up to a sound that is tuned for frivolous fun but is also deceptively technically adept.
The KZ ZS7 sports a powerful bass that also happens to be well controlled and impressive overall. It’s quite linear from sub to mid-bass and has very good extension and plenty of authority. Well north of neutral, the bass packs a punch but its relatively fast decay means there’s little bleeding into the mids.
Sub-bass rumbles and can be felt as well as heard and although it looks aggressive in the measurements I never found it to be intrusive or over the top. Overall, the ZS7 does bass incredibly well for a budget IEM and it’s definitely a highlight of the presentation.
There is a solid boost around 2-4 kHz that can be fatiguing at higher volume but at the same time gives electric guitars some fantastic texture and crunch. The ZS7’s warmth comes from its strong bass foundation. This means the midrange can be fairly neutral and uncoloured with good instrument separation and resolution.
Mids are recessed but do have good clarity. However, the upper mids are too boosted compared to lower and this creates an unbalanced presentation. Female vocals are vibrant but can become shrill along with pianos and other instruments in the higher octaves.
The ZS7 treble is fairly tame, especially in comparison to the upper midrange. I actually quite like this treble as it’s crisp with well-defined notes but at the same time it’s easy on the ears and doesn’t cause fatigue.
Cymbals have good timbre and realistic decay that provides natural sheen and some airiness. I think this is one of the better trebles I’ve heard from KZ in recent times but unfortunately it’s placed behind the aggressive upper midrange which tends to dominate on certain recordings.
The soundstage is neither particularly large nor small but about average for a budget V-shaped IEM. There is more width than depth along with a decent amount of height. Imaging is decent and the ZS7 is able to provide positional cues that aren’t razor sharp but are pretty solid.
KZ AS06 (3xBA $47)
The AS06 (review here) has less extension and quantity in the sub-bass but more emphasis on the mid-bass and a thicker, warmer lower midrange. It has a much better upper midrange tuning that has clarity and presence without the fatigue that the ZS7 brings. It doesn’t give electric guitars the same impressive texture as the ZS7 but it sure is a lot easier on the ears. The AS06 has a bit more treble energy but it is a little drier than the ZS7.
I find both earphones comfortable but the AS06 feels the best to my ears. However, I do love the premium feel of the ZS7’s metal housings. Although both IEMs come with the same standard KZ cable, the AS06’s cable has pre-formed ear guides which I much prefer over the memory wire on the ZS7 cable.
BQEYZ K2 (2DD+2BA $49)
The BQEYZ K2 (review here) has less sub-bass presence but a similar mid-bass quantity. It’s midrange is slightly warmer and more forward but has as good clarity and vocal articulation without any of the harshness that the ZS7 has. Vocals sound smoother and more tonally accurate on the K2.
The K2’s treble has a more realistic timbre and a sweetness that the ZS7 can’t match. Both IEMs have comfortable metal housings but the K2’s cable is far superior. Overall the K2 comes across as better to my ears. It’s more balanced, smoother and sounds more natural which is why it still has a place in our Best Universal IEMs list.
CCA C10 (1DD+4BA $40)
The CCA C10 (review here) has less sub and mid-bass which is also less textured than the ZS7’s bass. Its midrange is less recessed and has thicker notes but is still very resolving with excellent instrument separation. Vocals are smoother and sound more rich and vibrant on the C10.
Taking a very relaxed approach in the treble the C10 is extremely smooth and non-fatiguing but that huge dip between 4.5-9 kHz takes away some of the excitement and sounds more dull than the ZS7’s treble.
I find the C10 to be more comfortable of the two and also prefer its cable which is the same as the one that comes with the KZ AS06 (ear guides vs memory wire). With the C10 costing around $9 less, it gets my recommendation over the ZS7.
The KZ ZS7 is a well-built and attractive earphone that has a lot going for it. But for me, the upper midrange emphasis is a deal breaker because of its fatiguing nature and the way it takes away from the overall tonal balance.
On its own the ZS7 is actually a good product; it has excellent detail retrieval and great bass. However, in recent times there have been so many really stellar sub $50 IEM releases (several from KZ themselves) which has made the budget segment incredibly competitive. As such I think there are better options out there but if you happen to like a boosted upper midrange then you might really like this one.