Kiwi Ears Singolo English Review

 

Subwoofer For Bass-Heads

 

Ratings

 

Construction and Design
88
Adjustment/Ergonomics
85
Accessories
55
Bass
86
Mids
72
Treble
85
Separation
71
Soundstage
70
Quality/Price
78

 

Pros

 

  • The Kiwi Ears Singolo try to carve a distinctive niche for themselves among so many similar IEMS.
  • Voluminous and powerful bass, thanks to the good innovation of the KARS.
  • Soft but well extended and natural treble.
  • Pleasant and musical tuning from the midrange onwards.
  • Very good comfort and ergonomics.
  • They arouse a mixed feeling, sometimes they seem quite good, sometimes not so good.

 

Cons

 

  • They need some break-in, power and volume to «wake up» the midrange and high frequencies.
  • Technically average.
  • Sound somewhat compressed in layers.
  • Specialised profile, not for all tastes.
  • Very sparing in accessories for the price.

 

Purchase Link

 

https://www.linsoul.com/products/kiwi-ears-x-crinacle-singolo

 

Link to the Store

 

https://www.linsoul.com/

 

Introduction

 

Kiwi Ears are a small international group of engineers with the sole aim of producing the best sounding audio solutions for musicians and audiophiles. They focus on developing the latest driver technology innovations with refined tuning strategies that reveal all the nuances of music and performance. This time, they have collaborated with Crinacle, one of the world’s most reputable audio critics, to create the new Kiwi Ears Singolo. The Singolo is a custom 11mm dynamic driver IEM featuring the revolutionary Kiwi Acoustic Resonance System (KARS). KARS is a discrete bandpass filter that manipulates the airflow to the driver, regulating the low-frequency output. This patented innovation features an elaborate labyrinth-like network of tubes that has been designed based on numerous scientific and physical models to perfectly calculate the right resonance point for the Singolo transducer. The KARS makes a tight subwoofer shelf possible, something that was previously impossible in a single-transducer IEM. Unlike traditional crossover filters that use multiple transducers with RC (resistor-capacitor) networks, KARS uses Helmholtz resonance to regulate their tuning. The airflow to a dynamic transducer regulates how much the diaphragm can respond, but also requires additional calculations of flow rate, direction and volume. The KARS allows precise regulation of this airflow to manipulate the sound as desired. While capacitors and resistors provide a calculated medium for crossover solutions, they also add unwanted artefacts to the sound in the form of distortion, especially when using cheap SMD components. With KARS, the sound you hear comes directly from the transducer itself, resulting in a pure, higher resolution audio experience without the encumbrance of passive electrical components. KARS is 3D printed to an accuracy of 1.0 micron. The Singolo incorporates a custom Japanese liquid crystal polymer (LCP) diaphragm driver. This 11mm dynamic transducer has been custom created for the KARS, with unique front and rear acoustic chamber profiles. The Singolo is tuned according to Crinacle’s tonal signature. It is a synthesis of all the best tuning profiles found in the world’s most successful headphones over the years. With an 8 dB sub-bass boost, the bass is incredibly punchy and powerful, but cuts off impeccably at 300 Hz. This allows for a neutral midrange that articulates the natural sound of vocals and instruments without any artificial distortion. The treble follows the perfect compensatory curvature of the pinna, with a clean peak at 3 kHz and a natural roll-off into the upper treble.
After all that talk, let’s see how the Crinacle Kiwi Ears Singolo really perform.

 

 

Specifications

 

  • Model: Kiwi Ears x Crinacle Singolo.
  • Driver: 11mm custom dynamic driver + KIWI Acoustic Resonance System (KARS).
  • Frequency response: 20Hz- 20kHz.
  • Sensitivity: 108dBSPL/mW.
  • Impedance: 32Ω.
  • Capsule material: Resin.
  • Cable length: 1.2 meters.
  • Connection interface: 0.78mm.
  • Plug type: 3.5mm SE.
  • Mouthpiece inner diameter: 4mm.
  • Suitable ear tip size: 4-4.5mm.
  • PRICE: $79.00 USD.

 

 

Packaging

 

The Kiwi Ears Singolo comes in a medium-sized box with a mix of blue and black background. Its dimensions are 146x122x38mm. On the main side you can see, at the top, the logo of the brand and also the Crinacle logo. In the centre there is a real photo of the capsules on gold ink brushstrokes. At the bottom is the model name and a short description of the model, all in white ink. On the back, at the top left, are the logos of all the certifications held by the product. To the right is the brand logo in large print. In the centre, the model name and description are repeated. At the bottom are the brand name, e-mail address, web address and distributors. Removing the cardboard cover reveals a black box with a silver brand logo in the centre. After opening the lid you can see the IEMS with the cable inside a black foam mould. Underneath is a black cardboard lid with the brand logo in silver. Under that cardboard is the rest of the cable and accessories. In a nutshell:

 

  • The Kiwi Ears Singolo x Crinacle.
  • A silver-plated single-strand cable coated with clear PVC.
  • Three pairs of black tips sizes SxMxL.
  • Three pairs of white tips sizes SxMxL.
  • One instruction manual.

 

And nothing else. For a set costing around $80, there is no storage bag or pouch. The cable is just average, with a tendency to stiffness, although I like the curved design of the plug sleeve, as well as the 2Pin 0.78mm connectors, and the cylindrical metal cover installed on all these parts. The tip set is standard, completing a limited accessory set for the price.

 

 

Construction and Design

 

The capsules of the Kiwi Ears Singolo are made of resin. They do not have a semi-custom shape, but a classic one, with a triangular outer shape with rounded corners and a smooth, but continuously curved inner side. The outer face is blue on a fluid micro glitter base that varies in shades of blue to white, with almost pinkish tones in between. In the centre is the brand logo in silver. The capsules are relatively thick compared to the small-medium size of the set. The inner face is completely transparent, emphasising the visibility of the internal construction and those ducts that make up the KARS. You can see a duct that connects the driver output face to the base of the driver and then that labyrinth-like duct that connects a plate above the base to the output at the edge of the capsule. Enlarging the photo you can see the steps of the KARS made with 1 micron precision. The driver is relatively large, 11mm, coated in metal, while on the side near the apex you can read the name of the brand written on that cylinder. The inner side is very rounded and the transparency allows you to see the driver diaphragm at the base of the mouthpiece. The mouthpiece is metallic, with a minor diameter of 5.3mm and a crown of approximately 6.55mm. The total length is around 4mm and they are protected by a multi-perforated metal grille. Finally, the 2Pin 0.78mm connection interface is fully integrated into the rim of the capsules and is gold-plated.
The cable is a simple transparent strand whose conductor looks like silver-plated copper. It is somewhat stiff although not very thick, which is classic when it comes to this translucent PVC coating. All connector sleeves are curved and made of a whitish plastic. They are small parts with a cylindrical metal cover. The gold-plated 3.5mm SE plug is located near the cable outlet. On the 2 Pin 0.78mm connection interface it is at the base of the two gold-plated pins. The pin is at 90 degrees while the sleeve of the 2Pin connectors does not reach that many degrees, although it is clearly curved. The splitter is a smooth metal cylinder and the pin is a translucent plastic piece with a double through-hole. It is effective enough to hold the adjustment.
As you can read in the introduction, Kiwi Ears seems to have gone all out on the interior design of the capsule, with the patented KARS replacing any electronic crossover filter. In the end, it looks like a simple labyrinthine duct that has been seen in other IEMS. Otherwise, the capsule’s exterior design is pleasing, very rounded, with generous nozzles in diameter although somewhat short. The cable, given the price and the scarcity of accessories, could be better. There is no choice of balanced plug.

 

 

Adjustment and Ergonomics

 

The size of the capsules is small-medium, somewhat thick. Their weight is very light. All this, together with a very rounded shape, fits very well in the pinna. The problem comes with the diameter of the mouthpieces and their length. Their projection is very good, as is their inclination. But the thickness can be a bit big for some ear canals. Not for mine, whose diameter is quite large. Using my large tips filled with a lot of foam, I get that classic occlusive and long-lasting surface insertion. The good shape of the capsules limits rotation and the isolation, using my homemade tips, is very good. However, it is clear that the use of these specific tips, together with the diameter of the mouthpieces, can lead to some fatigue over the hours, despite the large size of my ear canals. Nevertheless, the ergonomics are more than remarkable and quite durable.

 

 

Sound

 

Profile

 

The profile of the Singolo is somewhat peculiar, oscillating between a V-U, with that excitement in the sub-bass and midrange. However, the highs are quite nuanced and, perhaps, that is the crux of the matter. Thanks to the KARS, the bass is the star of the show. Designed to sound like a subwoofer, the Singolo’s bass is big, voluminous and wide, even if it has a distinct drop-off as it enters the low-midrange. The first half of the midrange feels a little sunken and the midrange stays there until a gentle rise up to 4kHz. From that point on, there is an abrupt drop and the treble softens up a lot. It is not a dark profile, but rather a more nuanced and softened profile in brightness, sounding a bit dry and sparse, a bit forced.
Finally, the Kiwi Ears Singolo are somewhat difficult to move.

 

 

Bass

 

Without a doubt, the bass of the Kiwi Ears Singolo is big and voluminous. The low end is certainly intrusive and permeates the entire soundstage. It’s a bass with range, medium speed, that lingers in the room. It is relatively agile, but its strength and effect is felt in the air and in volume, it stays in the head and is not so quick to collect itself. This makes the spin more impressive, but the hit is effective, well-drawn and very punchy. It is not a dry hit, but juicy, but relatively well defined. It has a good dose of texture, plenty of bounce and power, both physical and sensory. And that shows in the very low frequency pure tone test. The low end is quite sensory with an audible undulating part. But, that sensory point possesses a good degree of power that comes to stun, like a dull kick. You can clearly perceive the power in the sub-bass and its sensory power. As the frequencies increase, this energy becomes more audible, but remains shattering and vast. Are the Singolo IEMS for bass heads? From their overwhelming behaviour in the sub-bass, I would say yes. That mix of sensory and physical power, coupled with the volume it generates, makes me think it can be included in this category.
Finally, in the test of dirty bass, unfiltered bases, complex and mixed bass lines, the Singolo’s proved remarkably adept. Despite the grandeur of their bass, it is true that their intonation stops at the point where the midranges begin. From 20Hz to 250Hz there is a 10dB drop designed to deactivate the bass in the midrange. Does it succeed? It’s tricky, but it works up to a point. On the plus side, the Singolo’s are able to execute complex passages with a good level of definition, without clumping and without sounding drowned out or muddy. Admittedly, there is a lot of rumble and it is not one of the fastest basses to recover. But there is some ability to follow the lines, as long as they are not too fast. But, it is also true that the lines can get stuck together due to their own power and the volume they occupy in the atmosphere. This makes it not the cleanest when it comes to reproducing fast bass lines or layers. But, so much power is not easy to make disappear.

 

 

Mids

 

The brand itself says that «the bass is impeccably cut at 300Hz. This allows for a neutral midrange that articulates the natural sound of vocals and instruments without any artificial distortion.» The truth is that the first half of the midrange feels relatively sunken, more so, if the music has bass. In electronic music with vocals it is clear that the power of the bass affects the ambience and tends to crowd out the vocals. For a male range that already feels medium-distance, with a lean body, a somewhat dry sonority due to limited harmonics, the Singolo would not be the best choice if you want to enjoy it. When the bass is not very present, there is a tendency to want to turn up the volume to bring these male voices closer, because their sonority, although somewhat sparse, is felt in an analogue but muffled way. This implies a release of full sibilance, but leaves them with an unjuicy, mostly dry, dark-leaning body. On the other hand, the female voices don’t stretch towards brightness either, despite the emancipation of the pinna gain. It is true that they are favoured, but they remain on a plane that is not entirely protagonist. Feminine sibilance can become subtly visible in those songs prone to it. But it’s a thick, rounded, nuanced sheen, never penetrating, and brief.
In the rest of the instrumentation, this dull, dry, nuanced quality persists. In my opinion, the natural sound is more vivid and also more sparkling, without being annoying, of course. However, the Singolo’s are too secure in this respect, as well as being somewhat distant. Do they sound good? As I say, there is a tendency to turn up the volume to enhance the fullness of the midrange and, as long as the bass doesn’t appear, they can come across as fuller and more balanced. At that point, more enjoyable midranges appear, slightly soft, dark, yet musical. But that does not detract from the imbalance in the bass.

 

 

Treble

 

To describe the high end, I refer again to the manufacturer’s notes: «The treble follows the perfect compensatory curvature of the pinna, with a clean peak at 3 kHz and a natural decay towards the upper treble». Are the treble natural? Perhaps I could say they are naturally smooth. It is true that I have been commenting that the sound is muffled, dry and nuanced, that the harmonics are not felt very much. However, if we talk about pure treble, it is true that it is there and expressed in a more natural way than I had thought. With that initial peak at 4kHz and a steep drop of another 10dB, the treble is stretched into the air zone by means of a controlled undulation. The result is a high end that doesn’t have a lot of energy, but is more homogeneous and realistic than expected, sounding smoothly natural and analogue. It is also descriptive and extensive enough to provide a good level of information. The downside is that the treble also feels a bit off from the midrange, hence the harmonic hollowness in the central range. In addition, their low energy also means that more power is needed to perceive them individually. The effect on the rest of the music is that their presence is relatively average.

 

 

Soundstage, Separation

 

The scene is predominantly frontal, a clear sense of volume at the bottom giving it a good level of depth. However, it is not too wide. There is a correct lateral sensation and not too much headroom. The feeling is of a more compact and unified sound, where the separation is not very obvious, nor is the layering or stratification. Beyond the volume and space occupied by the bass, the midranges feel homogenous and fairly cohesive, something that keeps the sound from being too technical or possessing too much resolution. If the songs have enough treble, the ensemble responds in a more airy way. Otherwise, the feeling of dryness, sparse and relatively dark sound, will detract from the detail. With corresponding power, detail can come to the fore and the sound becomes cleaner. But, even in that scenario, the detail is somewhat coarse and not very well defined, declaring a medium resolution and a rather average technical behaviour. It is clear that the Singolo are more musical and fun in their bass section, than technical.
The image is just OK and not very remarkable in this department either.

 

 

Comparisons

 

TKZK Ouranos

 

The TKZK Ouranos struck me as IEMS that were in the middle of the tuning of the late 2022 and early 2023 TinHiFi’s (T2 DLC 2022, T4 Plus, C2 and C3). They were the softest in treble and with a bass in the middle. Personally, I have to say that I liked them a lot. Their ergonomics are a notch above the Singolo, due to their semi-custom shape. The cable is almost on a par, although the Ouranos is stiffer. In terms of accessories, both are very sparse, but the Ouranos come with a small cloth bag. The current price of the Ouranos is $55 compared to $79 for the Singolo.
What can you see from the comparison of the two frequency responses? You could almost say that the Ouranos are a Singolo with a softened subwoofer. Their curve is more balanced and rounder, with slightly more irregular treble. Subtly more sensitive, the Ouranos’ profile seems more homogeneous, balanced and fuller. There is some similarity in the way the bass of the two IEMS performs, neither is too fast and the power control found in the Ouranos gave it a certain amount of joy and vigour. In the Singolo this character is clearly enhanced and it does feel like a more exaggerated Ouranos in the sub-bass, but also less compact and staying more in the room. The LFOs work quite well on both IEMSs, executing the pure tones very well, but with that familiar sensory and physical superiority of the Singolo. But so much power is difficult to dissipate and with a texture that is also complex to smooth out.
The midrange is more disconnected from the bass on the Ouranos, but they have that nice, musical warmth, which gives it more body, a more physical part and more presence. The first half of the midrange is closer in the Ouranos and male voices appreciate it. In the Singolo there is a point of sinking in that first half of the midrange, which unbalances the central range, leaving a certain gap. At that point, the Ouranos seem more natural and with better timbre. They are relatively equally dark. That they are thinner in that first half gives a point of clarity to the Singolo, less warmth in exchange for being leaner and thinner. That warmth of the Ouranos is also transmitted to the midrange and the female voices also feel fuller and rounder. I think the midranges, despite the dark and warmth of the Ouranos, are better than on the Singolo. However, the highs of the Singolo are better achieved than in the Ouranos. They don’t sound the same, despite the similarity. I find the high end of the Ouranos a bit more strident, while the Singolo’s treble reproduction is more homogeneous, even coherent. In the Ouranos I feel a certain disconnection in some points, while the Singolo show a more balanced behaviour throughout the range.
On a technical level the Ouranos dare to hint at the micro level. Despite the darkness and its softness, there is more space between layers and a richer background can be glimpsed. In it, certain details can be noticed. Those same details are more buried in the Singolo’s because they sound flatter and tighter. That level of layering gives the Ouranos more of a sense of depth throughout the range. Therefore, I think there is a point more resolution and detail, even though the Singolo’s seem more defined because they are thinner.
The scene is more voluminous in the Singolo, but I find the presentation of the Ouranos to be more spacious, with that better layering. Their better balance between bands means that, by giving them more power, there is no imbalance and you can see the size of their scene and better laterality.

 

 

Conclusion

 

Every brand seeks to innovate and in this regard, I find Kiwi Ears’ work in creating the KARS commendable. It is clear that their bass is distinctive, creating IEMS that combine a power for bass heads, along with a tuning that tries to be smooth and natural. Thanks to the KARS, the Singolo’s bass comes close to the behaviour of a subwoofer. But that very power makes them a specialised IEMS, which distinguishes them from an all-terrain IEMS. Kiwi Ears may have sought to create IEMS for bass heads, but without sacrificing a certain degree of naturalness and realism. In this sense, it succeeds in the treble. However, the clear intention to disconnect the bass from the midrange makes the first half of the middle range relatively hollow. On the other hand, it is more musical and smooth than technical. And in the price range in which it moves there is a lot of competition with very good resolving abilities. But I think the Kiwi Ears Singolo need not compete with them, but with that other IEMS range for bass heads that lacks that more audiophile level. The Singolo’s niche is in that area, not in the wide range of IEMS based, more or less, on the Harman curve. And that is where they excel and should be taken into account.

 

Sources Used During the Analysis

 

  • Hidizs S8 Pro Robin.
  • EPZ TP50.
  • Burson Audio Playmate 2.
  • Aune X8 XVIII Magic DAC + EarMen ST-Amp.