A gorgeous IEM to add to your collection

If you are at all interested in building a collection of IEM’s, I believe that you should have at least 3 different IEM ’tunings’, a balanced ‘Harman’ IEM, mid forward/centric tuning and finally a V-shaped ‘fun’ IEM tuning. Having a small collection with at least these 3 options really allows you to get the best from a wide range of your music, each IEM in your collection can extract different aspects of the music and the Forteza makes a great choice for those looking for a V-shaped tuning.

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Read on to see if it is the right IEM for you to add to your collection.

Design and Build Quality

The Forteza utilises a fairly unique combination of drivers with 2 Dynamic Driver’s (one for bass and one for the midrange) and a single BA handling the treble. This is an excellent design choice as it lowers the potential for any distortion (if you were to really push these IEM’s) where each driver has a set range of frequencies to handle.

Whats in the box

The Kiwi Ears Forteza comes in a nice box with a three sets of ear tips and a pretty good cable for this price point. kiwi-ears-box.jpeg

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I do like a little bit ear-tip rolling so having a good variety of stock ear tips is great but as you will see later in the review, I also tried and measured a few others ear tips to get the best sound out of these IEM’s for me.

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The Kiwi Ears Forteza boasts a gorgeous slightly transparent shell housing where you can see the drivers. As a nerd I always appreciate being able to subtle see the electronics inside the shell, unlike ‘dark’ shells used typically on the many IEM’s at this price point. The shell does give the Forteza a premium look and serves as a taster for the premium shells available on some of the more expensive Kiwi Ears models.
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Comfort and Fit

The design of the Forteza ensures a comfortable fit for most users. The earpieces are ergonomically shaped, and when combined with the right selection of ear tips, they provide a secure and comfortable fit, making them suitable for long listening sessions or even out on a long walk. I found as comfortable as my Kiwi Ears Orchestra Lite and a more stable fit than my Gizaudio Chopin’s.

Hopefully in this comparison photo you can see that the nozzle is smaller than the Truthear Zero and therefore for most people it will be a much more comfortable IEM to wear (the Forteza is on the left): Nozzle Size Comparison.jpeg

As a size comparison, here is the Truthear Zero, the Kiwi Ears Orchestra Lite and finally the Forteza on the right: Comparison2 Medium.jpeg

Overall, I found the shape of the shell used on the Forteza as well as the nozzle size to the perfect shape for my ears.

Sound Quality

So as I mentioned in the intro the Forteza has a ‘fun’ V-shaped sound signature, I believe this is a good move by Kiwi Ears as the current IEM is flooded with good and cheap ‘harman’ tuning IEM’s like the Truthear Zero Red while the there are not many quality V-shaped IEM’s priced less than $100 making the Forteza a great deal at $59.99.

Lets get into what you can expect from the sound of the Forteza …

Bass

The Forteza’s excellent bass is immediately apparent, it is both deep and punchy, catering well to genres of music that benefit from a more robust low-end presence. The bass is not overly dominant in any one area so even listening to a ‘sweep’ you get a smooth transition through the bass frequencies, allowing for a balanced listening experience without overshadowing the mids and highs. It’s a perfect V-shaped bass, giving you a visceral bass punch yet still allowing the treble detail to shine through. So on tracks like Billie Ellish’s Bad Guy and Xanny sounded great and Massive Attack’s Angel had that bass punch it needs without overwhelming the treble.

Mids

Despite the V-shaped tuning, the mid-range remains surprisingly clear and detailed and though I did find in some track that the vocals
took a slight backseat to the more pronounced bass and treble frequencies. That said tracks some very mid-centric tracks from the classic Elton John “Goodbye Yellow Brick Road” album sounded better than I have heard them in a while with the overall listening session getting something unique from that classic recording. So I believe the Forteza is suitable for a wide range of musical genres and will allow you to hear your music in new and unexpected ways.

Interestingly, I found the Forteza almost the opposite tuning of the Kiwi Ears Orchestra Lite which is mid-forward, so between the 2 Kiwi Ears IEM’s you get a very interesting contrasting music experience which is great fun to try on your collection.

Treble

The treble range is where the Forteza truly distinguishes itself. While exhibits an elevated treble response, which contributes to an overall sense of clarity and detail in the music. This elevation in the treble range enhances the listening experience for tracks where high-frequency details are pivotal. However, this elevation might, depending on your preference, occasionally lead to a perception of sharpness or sibilance, particularly in tracks with already prominent high frequencies. So, for example, in the new Japanese House song ‘Over There’ I felt the treble on the female vocals where a little sharp. This is where either some EQ or some ’tip’ rolling can be used to relax the treble frequency slightly.

Soundstage and Imaging

The soundstage of the Kiwi Ears Forteza is commendably wide for an IEM in this price point, providing a sense of space and directionality that enhances the overall listening experience. I believe the high quality drivers mixed with the elevated treble help provide some precise imaging, allowing for accurate placement of instruments and vocals within the soundstage.

Specifications and Measurements

Here are some of the key specifications:

Technical Specifications
Sensitivity (1KHz) 103 dBSPL/mW
Frequency Range 20Hz-20KHz
Impedance(1KHz) 32Ω

The specifications show that the Forteza is very easy to drive, a simple Apple USB-C Dongle adapter could be used when on mobile and these IEM’s will sound amazing without needing to switch to high gain on even a modest desktop headphone Amplifier. I tried them on various equipment from an Apple USB-C dongle onto my iPhone 15, with the headphone jack on my Macbook Pro and with various desktop headphone amps including the FiiO K11 and K7.

Measurements

These measurements were carried out on my IEC711 ‘clone’ coupler using REW

I decided to measure the frequency response various ear-tips provided with the Forteza as well with 2 sizes of ‘flange’ based ear-tips and a comply foam ear tip.

Firstly here are some measurements of the different ear-tips provided:

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As you can see the different stock tips had a very similar response.

But as I mentioned earlier I am a big believer is getting the right ear tip for you for a given IEMs as this can change not only how well they fit in your ear (so how they affect the bass response) but can also affect the treble (sometimes increasing and sometimes decreasing the treble) depending on your personal HRTF and I did feel when listening to this IEM that some people will like a slightly reduced treble in specific regions and a different Ear tip is a great way to subtly manipulate the treble response.

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So for example the triple flange reduced the treble peaks, but this effect will be different as everyone ear shape is slightly different, but I think it’s a great way to tame the treble response if you have a bunch of different ear tips to play with.

Finally, here is a comparison of the Forteza with a few other IEMs:

comparison-other-iems.jpeg As you can see the Forteza has great bass and an elevated treble (which can be tamed as I mentioned above) and slightly recessed midrange giving it that classic V-shaped sound signature.

I have uploaded all these measurements and others to the new Pragmatic Audio Measurement Database here

Distortion

I did noticed that the 3rd harmonic was a little high in the midrange - but still below audible limits - just posting it here for completeness:

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Rating

I have given the Forteza a pragmatic rating of 4, it’s V-shaped tuning while a great addition to a collection is probably not for everyone but the Forteza represents a good deal for a quality IEM with the looks and comfort of a much more expensive IEM.

Conclusion

Note: I would like to thank Lillian @ Linsoul for providing the Kiwi Ears Forteza - if you are interested in purchasing it here is a non-affiliated link to their store: here

The Kiwi Ears Forteza are a compelling option, particularly for listeners who are looking for something different than the usual ‘Harman’ sound and wanting to build their IEM collection. It’s robust bass response, detailed yet slightly recessed mids, and treble make it a versatile choice for a variety of music genres. While the treble elevation might not suit all preferences, it contributes to the clarity and detail that many will love, using some alternative ear tips can also tame the treble for those who find it too much. The combination of sound quality, comfort, and build quality makes the Forteza a noteworthy IEM in its price range.