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Review - HZSound Heart Mirror Pro

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Also available on YouTube in Spanish: Acho Reviews YouTube 

The HZSound Heart Mirror Pro have been sent to me by KeepHiFi in exchange for the publication of this review. They have not requested anything specific and I will follow my usual procedure of aiming to be a unbiased and sincere as possible, although it is always good to remember that these IEMs have not actually cost me anything.

You can find the Heart Mirror Pro via KeepHiFi here:

As always, the above is a non-affiliate link, therefore I do not receive anything by you clicking or even purchasing via the link.


Back in 2021, HZSound released the Heart Mirror, a set of budget IEMs that received quite a lot of praise from the IEM community. Personally I ever got to hear the Heart Mirror, not because I wasn’t interested but it’s impossible to get to try all of the models that are released!

Fast forward to far more recently and KeepHifi reached out to see if I was interested in trying out the Heart Mirror Pro, the follow up from the company which does come in at a higher price point (around 80 euros) but also offers upgrades from the original, at least that is what is advertised.

I obviously can’t go into comparisons with the original as I haven’t heard it, but I was more than happy to try out the new Pro version and share my opinions on this set which, while not in the extreme budget category, is still something that can be considered a relatively cheap IEM.


The box is a dark blue one, with a sketch of the IEMs on the front and information on the rear. It is not something that draws attention to itself but doesn’t look overly cheap either.

Upon opening the box, we find the IEMs sitting with their cable attached in the upper half of the interior, with card showing the HZSound logo covering the lower half. Removing this card, beneath it we find the user manual and the storage case.

Inside the case we get a second cable, this one with an inline microphone (terminated in a 4 pole, 3.5mm), 8 sets of tips (in various different sizes and types, including foam), a carabiner and the two additional connectors for the modular cable (more on that below).

In general, the presentation is more than adequate and the contents are very pleasing for a set of IEMs in this price range.

Build and Aesthetics…

I actually expected a mirror finish on the IEMs like the original model but I was actually pleasantly surprised to receive them in black. Not that I have anything against the mirrored finish but it does lend itself to becoming a fingerprint magnet (some black finishes do also, but not in this case). Looking closely at the finish, there is actually some grey (silver?) speckle to it, which is a nice touch, along with the HZSound logo in a dark bronze colour.

The IEMs are not very large, in fact, they are on the smaller side of things, and I find them to be rather comfortable. If they were any larger, the triangluar shape at the bottom may have been a problem but that is not the case. They are completely made of metal and seem to be well assembled and I can't spot anything that I would say is a going to be a problem over time as far as durability (but, as always, only time will tell).

The included cable is rather thin and a little rubbery but is not bad and a a very positive thing is that it comes with a modular connection system, including 3.5mm, 2.5mm and 4.4mm connectors. While it may not be on the level with some of the other (more expensive) modular systems, it works well and it is very nice to see it included. They also opt for standard 2 pin connectors at the IEM end, so I have no complaints here either.

The included case is also a very nice one. It is quite spacious (enough to hold the IEMs, some accessories and even something like the Go Blu) without it being overly bulky. I don't carry it in my pocket but it doesn't take up to much room in my small sling bag that I carry (yes, I’m a bag guy 😉).

In general, I have to say that I am quite happy with the overall quality of the IEMs and accessories for their price point.


Let’s start with the usual look at a graph comparing the Heart Mirror Pro with my usual preference target curve.

Start off with the subbass, we can see on the graph that it is north of my usual preferences, however, as it is kept clean and well detailed, it does not become overpowering. In fact, if I hadn’t have looked at the graph, I would have guessed that this has less subbass than it actually does. It is not missing subbass, “Chameleon” has plenty of rumble, but at the same time, it is not a set that I would class as a bass head set.

The midbass is also a little elevated for my personal preferences but again, it doesn’t become over powering nor does it become the center of attention. I have said in the past that if something is tuned higher than I prefer in the bass range but still manages to keep it clean and detailed, chances are that I am going to enjoy it. The Heart Mirror Pro is one of those sets.

It is true that the low end of the guitar in “Crazy” does have a little too much in the midbass area, which sort of gives it a bit of a boomy effect to said guitar, yet, as the mid range is well balanced (I’ll get there in a moment), it gives an overall clean and detail effect to the track in general, making for a very pleasant listen.

The additional midbass manages to decrease before hitting the lower mids, avoiding things becoming muddy in the bottom of the mids, something that is appreciated as it counteracts that midbass boost and makes things seem a lot cleaner.

I have to say that I find vocals, especially female vocals such as Daniela Andrade in the track “Crazy” that I just mentioned, to have just the right amount of presence and warmth in their lower ranges, making most of the acoustic music Iisten to very enjoyable. 

There is a little bit too much warmth for me to class the timbre of things like the acoustic guitar in “All Your Love (Turned Into Passion)” as correct, yet just because something may not be exactly what I consider correct, it doesn’t mean that it is bad. If I was wanting to focus on dissecting and equalizing music, then I wouldn’t suggest the Heart Mirror Pro in these ranges for that, but for enjoying the music, I have to say that I have had no problem in doing so with these IEMs.

Moving up to the higher part of the mids, I have to say that I am impressed with the tuning of the Heart Mirror Pro. It is almost a perfect replica of my personal preference, with a smooth climb that stays smooth and present from the 2kHz to 4.5kHz, starting to ramp down just before the 5kHz mark. I really couldn’t ask for a better tuning for my taste in this upper mids.

This works for the vocal centered tracks that I listen to, as it brings the voices forewards without them being overly present, harsh or nasal. As an example from my test tracks, “Seven Nation Army” by Zella Day, which is a track that can be very harsh on so many sets, is just right on the Heart Mirror Pro. I have heard it slightly less harsh on other sets but that is because they are actually taming it down. I feel that these, the Heart Mirror Pro, are giving the real presence of her voice, just on the verge of the harshness, as her voice actually is.

As we move into the higher ranges the extension is fairly good. I wouldn’t say it is the most extended, airy or open of IEMs in the treble ranges but it certainly doesn’t suffer from a pronounce roll off like so many other single DD sets. I wouldn’t say it is going to win any prizes in this range but it’s certainly not bad.

Using “Code Cool” as my usual judge of sibilance, I feel that HZSound has also done a good job here, with Patricia Barber being just on the verge of sibilance, which is were I feel that she should be when a set is nicely balanced in these ranges. She could maybe be toned down just slightly but I don’t think it is a reason for complaint.

Detail is not bad but is not excellent either. I find that the details that are more “up front” are easily identified and quite impressive but the smaller background details (such as reverbs etc.) do fade away fairly quickly. A good example of this would be the intro of “All Your Love (Turned Into Passion)”, where the initial strikes on the body of the guitar are impressive yet the room reverb does fade away quickly, leaving an impression of things being a little too tame (when compared to other sets that are better at this specific task).

In the soundstage category, I would say that they are around average, maybe on the higher side of the middle ground. There is a decent amount of soundstage but they are still very much IEMs. Image placement is decent but I do feel that things like “Strange Fruit” could do with a little more space between layers in the more complex parts of the track.

The isolation is a little above average, meaning that they should be fine for use in places with normal extenal noise yet they will suffer with things like the low frequency rumbling of engines on a plane or train etc.


The Heart Mirror Pro is a set of IEMs that I have enjoyed listening to and have no issues using as a daily general listening set. I don’t feel that they are ground breaking in any specific way, yet they are a solid performer in all of the categories. I could mention various areas where I think they could be improved but I don't have any complaints about anything specific with them at all. 

The lows may be a little elevated for my personal tastes but they are not irritating and the upper mids I find to be very well done indeed. The details retrieval may not be the best for those small nuances happening in the background but the overall detail of music is by no means bad and I don’t feel that those small elements are something to really focus on unles you are specifically looking to analyze the track.

The build is good, the included accessories are very good in the price range and in general, I just feel that the Heart Mirror Pro are a good set of IEMs for the 80€ price range. I certainly cannot complain about their performance. 

All FR measurements of IEMs can be viewed and compared on
All isolation measurements of IEMs can be found on

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