This is a review, measurements, listening tests and equalization for KZ ZSX IEM. It is on kind loan from a member and costs US $60.
Not much to say about the look of the unit. The owner sent me one set of tips which I used for measurements. They were kind of worn out but still worked out well. For listening tests, I grabbed one I had on hand which you see in the picture above. They did not provide a complete seal for long unless I kept pushing them in every couple of minutes. Expectedly, bass would response would drop some when that happened.
The unit has 5 BA and 1 DD driver. I assume the number 12 comes from two times six.
KZ ZSX IEM Measurements
As usual, we start with frequency response measurements of the IEM and comparison to our target:
I was relieved to see proper level of bass and generally good compliance with our target. For the purposes of EQ, we want to see the deviation from our target:
Distortion test revealed a clear problem with the design:
It is a shame more people don't do distortion tests as it so clearly demonstrates problems like this.
Group delay is usually clean with IEMs and such is the case here:
Impedance is flat and low:
Combined with good sensitivity, you should have no trouble driving these IEMs to loud levels:
KZ ZSX IEM Listening Tests and Equalization
Out of box experience was non-offensive but not exciting either. I expected it to sound better than it did give the small variation from target. Turns out those differences matter when we perform AB test with EQ correction:
The yellow filter gave the IEM huge boost in spatial effects, rising to delightful levels! The sharp filter in teal was put in there for distortion reduction. Without it the sound was a bit grungy and muddy (in limited blind testing). I initially put in correction for shortfall in higher frequencies with Bands 5 and 6. Alas, that made the IEM too bright after a few seconds of listening especially since I could not maintain good seal/bass response. So I disabled them.
Once there, the experience with my reference tracks was incredible! I often forget how great these IEMs can sound. Detail, resolution, and spatial experience per above, was superb. I didn't want to stop listening. The only miss was lack of deep bass as I have stated which may have been remedied using a different tip.
Conclusions
I very much like that KZ has made an attempt to give us bass and general response that is close to our target. The distortion is unfortunately though. My correction took a way of a bit of tonality to reduce that. Audibility may not be there due to narrowness of it but still, I like to see that remedied. Sensitivity is quite good unlike some otherwise excellent IEMs I have tested.
Overall I am fine with out of box experience so going to recommend the KZ ZSX. Add some EQ to it and this IEM becomes reference quality, blowing away vast majority of home systems.
Weight: 31g
Wear: In-ear earphone
Sensitivity: 111dB
Impedance: 24Q
Frequency: 7-40000Hz
Line Length: 1.25±0.04m
Plug Type: 3.5mm gold plated
Pin Type: 0.75mm gold plated
------------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
Not much to say about the look of the unit. The owner sent me one set of tips which I used for measurements. They were kind of worn out but still worked out well. For listening tests, I grabbed one I had on hand which you see in the picture above. They did not provide a complete seal for long unless I kept pushing them in every couple of minutes. Expectedly, bass would response would drop some when that happened.
The unit has 5 BA and 1 DD driver. I assume the number 12 comes from two times six.
KZ ZSX IEM Measurements
As usual, we start with frequency response measurements of the IEM and comparison to our target:
I was relieved to see proper level of bass and generally good compliance with our target. For the purposes of EQ, we want to see the deviation from our target:
Distortion test revealed a clear problem with the design:
It is a shame more people don't do distortion tests as it so clearly demonstrates problems like this.
Group delay is usually clean with IEMs and such is the case here:
Impedance is flat and low:
Combined with good sensitivity, you should have no trouble driving these IEMs to loud levels:
KZ ZSX IEM Listening Tests and Equalization
Out of box experience was non-offensive but not exciting either. I expected it to sound better than it did give the small variation from target. Turns out those differences matter when we perform AB test with EQ correction:
The yellow filter gave the IEM huge boost in spatial effects, rising to delightful levels! The sharp filter in teal was put in there for distortion reduction. Without it the sound was a bit grungy and muddy (in limited blind testing). I initially put in correction for shortfall in higher frequencies with Bands 5 and 6. Alas, that made the IEM too bright after a few seconds of listening especially since I could not maintain good seal/bass response. So I disabled them.
Once there, the experience with my reference tracks was incredible! I often forget how great these IEMs can sound. Detail, resolution, and spatial experience per above, was superb. I didn't want to stop listening. The only miss was lack of deep bass as I have stated which may have been remedied using a different tip.
Conclusions
I very much like that KZ has made an attempt to give us bass and general response that is close to our target. The distortion is unfortunately though. My correction took a way of a bit of tonality to reduce that. Audibility may not be there due to narrowness of it but still, I like to see that remedied. Sensitivity is quite good unlike some otherwise excellent IEMs I have tested.
Overall I am fine with out of box experience so going to recommend the KZ ZSX. Add some EQ to it and this IEM becomes reference quality, blowing away vast majority of home systems.
Manufacturers Specifications:
Model: KZ ZSXWeight: 31g
Wear: In-ear earphone
Sensitivity: 111dB
Impedance: 24Q
Frequency: 7-40000Hz
Line Length: 1.25±0.04m
Plug Type: 3.5mm gold plated
Pin Type: 0.75mm gold plated
------------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
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