Review - Kiwi Ears Allegro

Review - Ikko Opal OH02

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Also available on YouTube in Spanish: Acho Reviews YouTube 

After some time away from my review desk and a series of mini reviews, I am finally back to my normal set up and it is time to start making my way through a few things that have piled up while I was away.

The first on the list is the Ikko OH02 Opal, a set of IEMs that has been kindly sent to me by Hifigo in exchange for me publishing this review. As usual, the only request has been that I include links to the IEMs via their website, therefore my review will aim to be as unbiased as possible, although it is always good to consider the fact that these IEMs have not cost me anything.

You can find the Ikko Opal OH02 on Hifigo here:

And via Amazon US here:

(non-affiliate links)


Starting off with how these IEMs arrive, I must say that the packaging and contents are quite impressive and are certainly original, moving away from the usual way in which IEMs in these ranges are usually presented.

The box itself is large and colourful, as you can see in the image above, with a sleeve that has a shaped cutout to allow the artwork to show.

Inside the box we get the IEMs, as is to be expected, placed in a foam cutout that also includes an Ikko branded pin in a combination of gold an black. Personally I have no use for a pin but I always mention unexpected contents and I don’t think I have ever received a pin with a set of IEMs before.

Also in the box we get a cable, which I quite like except for the black covering for the pre moulded ear shape (which detracts from the nice aesthetics of the cable in my opinion) and the fact that they use MMCX connectors. To be honest, the MMCX connectors seem to be of good quality and look like they will last fairly well, but I guess MMCX is just a personal phobia of mine. 

Also included is a leather (imitation?) carrying pouch that is also different to any other pouch or case I have received in the past. It is actually more of a pouch that I would use for other things more than IEMs, and is closed by means of a leather string that wraps around the pouch. I can’t say that it is a great solution for IEMs but again, they deserve points for originality.

The last thing to mention as far as contents, other than the documentation that is in a nicely branded envelope, a couple fo replacement filters and a cleaning/MMCX extraction tool, is the amount of tips included. There are a lot. I don’t think that this is the most tips I have ever received but it is certainly the largest selection of uncommon tips I have received. As the nozzles are oval in shape (I’ll mention more about that in a moment), there is also a large selection of oval shaped tips included, with one set that is possibly the largest I have ever seen, along with a selection of hybrid foam/silicone tips. In total there are 9 sets of tips, so there should be something for everyone, well, maybe everyone except me, more on that in the next section.

Build and aesthetics…

As far as build quality, while all plastic (or at least I think they are all plastic), they do seem to be decently made and I see no issues with the build at all. 

In terms of aesthetics, in my opinion they are also good looking. The set I have received are a dark green colour, with a small transparent green tinted window that shows a circuit board below. As with the packaging, the aesthetics are original enough to be different but without being so off the wall to look strange.

When it gets to comfort, here I wasn’t quite as lucky, at least with the included tips. As the nozzles are oval, as I mentioned above, they have also included oval shaped tips. In my case, no matter which way I tried to orientate the tips, and no matter which size, I never felt that I could get a proper seal and they never felt overly comfortable. The result with some of the other tips was better but still not something that I enjoyed too much. In the end, I opted for Azla Crystal tips and these solved the issue of seal but I still didn’t find them overly comfortable.

The angle of the nozzle just seems to be a mm or two away from matching my ear anatomy and I always feel like they are putting pressure on the front of my ear canal. I will say that they are very light though, so there is no sense of fatigue from weight, even after long sessions of many hours, just that little issue with the pressing on my canal.

Obviously we all have different ears and this is only an issue for me personally, I imagine that these will be extremely comfortable for most people.


As we are back to my normal review format, I will mention that, as with all of my normal reviews, each track mentioned is a clickable link that will allow you to open the song in the streaming service of your choice. The measurement of these IEMs can also be compared with any other IEMs I have reviewed here:

Starting, as usual, from the lowest ranges, the Opal have quite a roll off in the subbass, however, due to a fairly boosted midbass range, they never seem to be lacking in the low end. If isolating the lowest notes, then yes, the roll off is noticeable, but I can’t say that it is something that I notice while listening normally.

Into the midbass, here there is a boost that does make itself the centre of attention in the low end. The mid bass is controlled fairly well and actually works ok for a lot of modern pop music, such as “Get Lucky”, but when moving to more acoustic focused music, I feel that the midbass focus makes it seem a little unnatural. Even with electrical based instruments as the focus but with simple songs, such as “Crazy”, I find that it is a little too present. In the case of this specific song, it causes a sensation of reverb in the midbass of the electric guitar and I can’t say that it sounds very natural.

Moving into the mids, there really isn’t too much bleed due to the fact that the midbass is fairly well controlled, meaning that while it is very present, it doesn’t interfere too much with the mid range. There is a slight dip in the centre of the mids and while the higher midrange doesn’t climb as much as it does on many other set, the vocals stay present for the most part.

I say for the most part as, depending on the instruments in play, the midbass boost can become a little overpowering and make the voices suffer a little to be present on certain tracks. This is something that I experienced on a lot of hip hop, such as “Bang Bang” for example, where that midbass can make the instrumental sound impressive but make the vocals seem to struggle.

One thing I will say is that voices do not come across as harsh, even “Don’t You Worry Child” is quite smooth in the vocal range (a track that I find harsh on a very large selection of IEMs).

Moving into the treble, there is actually quite a decent job done in this area to compensate for that midbass boost and not make the overall sound seem dark. There are occasions on which I find certain tracks to also be a little unnatural in the higher ranges but in general I feel that a good job was done to balance out the highs with the lows without becoming overly harsh in the upper ranges either.

The sensation of air and spaciousness is not bad, considering the low end boost, and while the soundstage is not large, more towards intimate I would say, it still doesn’t seem too cluttered, with things having space to breathe.

Last of all, detail. I don’t think that these can be considered highly detailed IEMs, yet they still manage to give a sensation of everything being in its place. I wouldn’t pick up these IEMs to find small nuances but at the same time, I feel that they can be enjoyed without the sensation of things missing.


The Ikko Opal OH02 is its own thing. From the packaging, to the aesthetics, to the sound, everything is different to normal but not so different it is “off the wall”.

As far as sound, it’s like an IEM that manages to be V shaped without actually being V shaped. Depending on your choice in music, that midbass boost will either be very impressive or irritating. If you enjoy vocals on hip-hop, or on bass heavy RnB, then that midbass does get in the way. I also feel it can be problematic with some of the simpler vocal/instrument tracks. However, when moving to more modern pop, it can actually be the opposite and work quite well.

At a price of less than 80€, I feel that you are getting a good deal on these IEMs considering everything you get, but the sound signature will not be for everyone. They by no means sound bad, they are just different, and whether that difference is for you, only you can decide.

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

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