Greetings Head-fi!
Knowledge Zenith (KZ) has been producing excellent earphones targeted towards budget-minded buyers for quite a while now, and they have a strong following on Head-fi. We collect these things like baseball cards (is that even a thing anymore?). There is good reason for this.
KZ earphones are made from quality materials, have interesting yet occasionally questionable designs, and most importantly they sound amazing compared to many other products in their price range, and well above for that matter. There are certainly exceptions and some true stinkers from KZ, but they are few and far between.
This bring us to the HDS1, one of KZ's final releases from the 2015 calendar year.
This unit was purchased through AliExpress. I am in no way affiliated with Knowledge Zenith or any AliExpress sellers. All opinions within this review are just that, opinions.
A Bit About Me:
I like to think I'm starting to get a grasp on this whole portable hi-fi audio thing, and can thank Knowledge Zenith and their army of budget earphones for helping me find my preferred signatures. My gear is constantly improving. I have finally upgraded to a quality phone, the HTC One M8, adding the Topping NX1 as my go-to amp. I primarily listen to EDM (liquid drum and bass ftw), hip hop, and classic rock, but have been known to dabble in metal and jazz. While I enjoy a good sounding earphone, physical design is also key. If they look boring but sound great, that's cool, but I would like to have something interesting to look that is also great sounding.
About the HDS1:
Normally this is where I would look at packaging and accessories, but in typical KZ fashion this is so inconsistent I don't see the point. One set of HDS1 I picked up came in a small cardboard box set within a larger cardboard box. The other in a plastic bag nestled within a nice carrying case. The point is that what I describe might not be your experience so packaging expectations should be set aside and focus placed on the earphone itself.
To get this out of the way now, know that micro-drivers, 6mm and smaller, are my favorite driver type. In my experience they tend to offer up quick, snappy bass, lots of detail, and result in tiny earphones that are almost always exceptionally comfortable. As with everything, there are exceptions, but the HDS1 isn't one of them. The tiny 6mm driver KZ stuffed in an equally tiny housing is a marvel at the sub-10 USD price point these can often be bought at.
The all-metal housing on the HDS1 is very small, very light, and very comfortable to wear. They don't tug at your ears or create any painful hot spots. They do however transmit an unnecessary amount of cable noise should you choose to wear them cable down, which is a big no-no to my ears. Cable noise is enough to ruin an earphone entirely for me if it cannot be quelled, so when I found that wearing the HDS1 cable up removed it from the equation almost entirely, I was a happy camper.
The cable itself is a KZ standard found on many of their other products, such as the ED10. I found that it was a pretty poor choice for the HDS1 since by it's very nature it is a noisy little thing. Combine that with a housing that projects this noise directly into your skull and things can get pretty distracting. At least the cable feels reasonably durable, though it is a bit thin and sticky. Not one of KZ's best cables, and in general, not one of KZ's highest quality earphones when it comes to material choices.
Sound:
Where the HDS1 fails to impress in it's build, it certainly makes up for it in it's sound quality. While the HDS1 has a bit of a boost to their mid-bass they offer up a mostly balanced sound, especially compared to the majority of KZ's lineup.
Treble is well-extended and nicely detailed without being too sharp or prickly, though it can run a bit dry on some recordings. As with the rest of the HDS1's signature, the HDS1's upper ranges are in general very musical and carry a beat well. They're never splashy or harsh, and are just pleasant to hear.
Mids on the HDS1 are slightly forward in my opinion, and as a result soundstage is smaller than I expected from a semi-open back earphone. It's not congested by any means, but it does give off a more intimate presentation putting you close to the artist. They sing at you, not to you. Both male and female vocals sound great, but I prefer the texture female vocals are given. Female vocalists (Hope Sandoval anyone?) with breathy voices sound particularly amazing through the HDS1. Males with higher pitched voices (ie. pretty much every male EDM or pop vocalist nowadays) benefit from the HDS1's presentation as well. Acoustic guitars pluck realistically and with just the right amount of grit and reverb.
There is a mild mid-bass boost on the HDS1. While I find it plays nicely with middle frequencies, the HDS1 does occasionally produce a bit of echo when undesired. For the most part though bass is well controlled and pleasant without ever being overpowering. It's plentiful enough for bass heavy beats, but polite enough to keep the HDS1 from ever sounding like a bass-heavy earphone.
Compared to other micro-driver earphones in my collection, the HDS1 stands out as one of the best. Out of the box I compared them very closely to RHA's obscenely good S500i. While I don't necessary agree with my initial impressions, I do still think that they compete with each other quite well. The RHA S500i is brighter with less forward mids and reduce mid-bass emphasis, although I think they dip into the sub-bass frequencies more effectively. I agree with @peter123 that the HDS1 is the darker of the two and falls short in clarity when put head-to-head. That said, the HDS1 is a more relaxed listen. The S500i's bright signature can be fairly fatiguing even over short listening sessions. They are two different but equally good-sounding earphones. The RHA whomps the HDS1 in build quality and accessories, easily making up that ~40 USD price difference and justifying the price jump if you want something a bit more "hi-fi" and premium feeling.
Overall Thoughts:
The HDS1 is really a no-brainer buy. While I paid about 13 CAD near release for each for mine, they can often be found for under 10 USD on AliExpress. When you take into the account the quality of sound you are getting, it becomes pretty easy to overlook their flaws. Yeah, the cable kind of sucks, mid-bass is ever so slightly boosted, and they probably won't come with anything but a few spare ear tips, but man do they ever sound awesome.
Thanks for reading!
- B9Scrambler
