Knowledge Zenith ES4

Even though this is slightly older or released couple of years before, still good. With eartips changed, the bass improved a lot. I used Soundmagic eartips and spinfit cp100 and observed the bass improved a lot. The cable is basic one and could be used for some time

Sound is good but definitely not to everyone's taste. Highs can get a little piercing. Not the best fit. The wire feels very weak. Other than that it is a great earphone for the price.

HiFiNage has exchanged Astrotec AS-200HD and gave me KZ ES4. So first of all, below is the experience of Astrotec AS-200HD and HiFiNage:

Actually I liked the product. But the product soft skin was peeling off when I received the item. I informed hifinage support. I really loved the way they responded to me to issue a store credit note to purchase another item. It was a master class service from them. I really recommend all the products to purchase what they are selling. They are very lovely and much more responsive and responsible. Loved to purchase at hifinage.
Warm Regards

Now the review of KZ ES4:
ES4s by KZ absolutely does their job. They are very balanced in-ear monitors for beginner audiophiles. They are perfect with foam tips for better fit and noise cancellation. Recently downloaded FiiO music app. These IEMs are doing good with that music player. One comment on Hifinage is They are very much responsive and Responsible. Really loved the support they extended when I required for a defective piece. Just choose any product and Trust them they will do rest till you receive the one. Warm Regards

My order was nicely packed and was delivered in time.

Timely delivery and great customer service from Hifinage.com. Looking forward to buying more stuff from them.

First impressions: A lot of people suggested wide bore tips for this. Tried stock tips, it sounded below average, muddy. Tried wide bore and the highs were gone, it was a mid-bass massacre. After an hour of replacing tips, tried the double-flanged one and voila. Tight controlled bass, minimal mid-bass bleed and focussed mid-range with a slightly harsh upper mid to lower treble (totally acceptable).

The low extension is fantastic, in addition to my reg music tried some movie trailers as well. Blasts, rumbles sounds fantastic with good depth but surprisingly recovers very quick as well. Checked with some electronic music like Dzihan and Kamien, plaster as well. Sounds very good. With any other tip except the double-flanged one, it reaches basshead levels which I personally never enjoy.

Mids are recessed yes but have good tonality and attack. Metal guitars(Dying Fetus, Cannibal Corpse, Krisiun, Origin) sounds very realistic with slight grain which I like. Softer albums like Seachange (Beck) sounds acceptable.

Highs are a little limited and tamed. Make no mistakes with the double flanged tip it gets very bright but still a bit limited and stiff(extension wise). Some track shows a slight hint of sibilance here and there but that's nitpicking.

Sound isolation is extremely spot-on as it fits perfectly in my ears. It's light, comfortable for long listening sessions.

The soundstage is decently wide horizontally but a little less vertically. Overall the 3-dimensional presentation is satisfactory.

Imaging is good overall, separation is decent too.

Extremely sensitive to tips. Never heard such a huge difference with different tips with any other earphones.

I don't wanna comment about cable quality etc at this price point. Removable 2 pin cable is provided whereas my one more triple doesn't come with one(and costs almost 3.5 times).

What a value for money. What a great time to be alive.