Page 3 - Subjective Audio Analysis
Reviewing audio devices requires extensively trained ears, lots of experience, and sufficient technical knowledge. Even for an experienced evaluator, it may be difficult at times to perform an accurate evaluation of a product without the aid of a thoroughly familiar product serving as reference. There are no truly objective measurements for audio sound quality, but as a reviewer, I will put the Belle IEMs through a series of subjective tests in an attempt to extract the most objective rating that I can. After using the Belle for upwards of 70 hours of break-in time, the audio tests were conducted with the Belle IEMs connected to a Lenovo IdeaPad Flex 5 via the 3.5mm audio jack. All audio files were sourced using songs from Spotify with audio streaming quality set to lossless 24-bit 44.1 kHz. All settings were left in the default state.
The overall sound of the Kiwi Ears Belle is an elevated bass with warmer mids and a rolled-off treble. It is not a true V-shape, as the mids are not recessed, being much closer to a warm-neutral with an emphasized bass. I would describe the character of the sound as warm, musical, and relaxed, prioritizing listenability over rigorous analytical precision.
Starting with the bass, at the lower end, the sub-bass performance was rounded and clear, possessing a soft edge with a consistent sense of weight. Above the sub-bass, the mid-bass and upper-bass were both full and well articulated. Bass guitar string vibration was clear enough to be visualized, while on the vocal side, in lower songs with multiple bass singers, the individual voices could be distinguished, even in subharmonics. Overall, I found the bass to be a strong showing, and I found myself able to listen to bass-heavy songs for extended periods without experiencing fatigue.
In the midrange, the Belle IEMs were generally clean and natural. Vocals, particularly male vocals, came through with good warmth and body. The Belle executes presence and bite without falling into harshness. Piano pieces making use of the sustain pedal and overlapping harmonic layers showed good resonance, allowing notes to naturally decay without noticeably losing clarity.
The Belle's treble was sufficient to avoid any impressions of darkness, but it rolled off on the upper end. Exceptionally high vocals such as whistle notes often sounded recessed, as though they were slowly retreating away. However, certain instruments tended to fare better. For example, woodwinds were pronounced and distinct, retaining their characteristic timbres, even up to the flute, and the hammered dulcimer, which keeps its characteristic tonal sweetness. Overall, the treble was cromulent and non-fatiguing, despite lacking a degree of air and sparkle.
As for soundstaging, the Kiwi Ears Belle is slightly on the narrower side but about average for an IEM. The single dynamic driver design and warm tuning mentioned earlier do not typically lend themselves to a wide or deep presentation. I found the imaging to be adequate. Directional cues are intelligible and at a level serviceable for gaming, although I noticed that if multiple directional cues occur at once directly in front or behind, the directionality can become muddied or confused. Any cues at an angle of greater than about 30° and less than 150° to the left or right of center were consistently very good.
In terms of layering, the Belle encounters no issue with simple to medium-complex tracks. More complex pieces such as orchestral pieces start to show signs of congestion. The frequency separation of the Kiwi Ears Belle is average. There is a tendency for the bass and mid-bass to blend. The treble is sufficiently separated but can feel recessed at times. The Belle does perform strongly in cohesiveness, where the single dynamic driver tuning produces a smooth, coherent sound without crossover inconsistencies. The cleanness of the Belle is fairly clean on the simpler tracks, but the mid-bass can cause some muddying in more demanding situations. I personally found that this was most pronounced in certain orchestral pieces with multiple simultaneous instrument sections and/or massive dynamic swings.
In terms of sound isolation, the Kiwi Ears Belle comes with three different sizes of eartips, which should work for most people's ear sizes -- important for comfort and passive noise cancellation. I found that the medium size worked best for me and proved to be effective at passive noise cancellation. I have commonly worn these IEMs during my morning commute, and they were up to the task of almost entirely blocking the sounds of public transit, people who try to preach at me, and street traffic. While they are obviously not as effective as ANC, once you have audio playing, only unusually loud sounds will interrupt unless you actively try to hear the outside world.
Overall, the Kiwi Ears Belle delivered a strong performance for its price point. On one hand, it provided a warm, well-articulated sound with a slightly recessed but acceptable treble, and its bass and mid-forward tuning produced a smooth, coherent listening experience. On the other hand, it showed signs of congestion with more complex tracks, and its soundstage, while adequate, is on the narrower side. Additionally, the treble rolled off in the upper end, leaving some high-frequency detail feeling recessed.
Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Hardware
3. Subjective Audio Analysis
4. Conclusion
