The iBasso IT04 pushes clarity and detail first, but smoothes those sharp edges with a liquid render. It excels at transparency, and accompanies it with authoritative weight and dynamism, achieving a well-rounded profile. Spaciousness, air, and body come together to give the IT04 a near-perfect audiophile experience.
Treble is sweet, silky, and beautifully extended. These are not shrill, thin highs. They possess such light and air, feeling limitless as they open the ceiling and reveal the great expanse of the universe. I suspect there’s a 6k bump for articulation, followed by a slightly larger upper-treble bump for its very open and airy quality. Though, where it really impresses is in that super extension. There’s no way to cheat that.
IT04 delivers vivid, highly textured, and clear vocals. They may not have a great amount of weight, but they are not thin or wispy, either. They are certainly more about articulation than warmth or lushness. If you favor fullness in your vocals above all else, the IT04 is perhaps not ideal for you. But if you seek clarity and detail in a smooth, non-fatiguing presentation, iBasso has a winner here.
Instruments have superb definition and really sparkle with dynamism. Electric guitars crunch in a very obvious way, and drum strikes are precisely located. There is enough body in the tuning to create authentic warmth for the midrange, though only barely. iBasso walked a tight-rope here, flirting with coldness or sterility, but managing to keep clear of such fatal flaws. I personally would prefer a little more warmth, but like I said, there is enough here to keep musicality and clarity in good balance.
The bass is highly dependent on the seal. Which is always true. And I do struggle to get the best seal with these. That said, there is enough bass. By no means is the IT04 bass-heavy. But with the right seal, the music fills out nicely and you get good, deep, well-controlled lows. Sub-bass is elevated, and then it slopes seamlessly into the mids. There might be a subtle hump in the mid-bass. But not much. Overall, the lows are more about speed and control than warmth and richness. Still, there is a slight coloration which comes from the bass which helps give the IT04 its unique sweetness and liquidity.
Soundstage is vast and wide. Separation and layering is excellent. Imaging is spot on. The IT04 has a particular affinity for resolution, which is remarkably sharp. Indeed, on technical merits alone, iBasso can justify its price-point. This is a killer performer.
While I did have a brief period with the IT03, it was long ago and I could not reliably compare the two. The IT01 ($99, Review HERE), however, I have on hand, and know quite well. Tuning is very similar to that of the IT04. Bass is sufficiently present, but not exaggerated. There’s lots of treble. And vocals are crisp and clear. Still, there is more to an IEM than mere tuning. The IT04 does not sound like the IT01. Its treble is sweeter and smoother. Less grainy and more refined. The mid-range is richer, possessed of a more natural quality. The bass is more or less the same, though. I would be hard pressed to state which one I preferred.
One of the best comparisons I could make is the DUNU DK-3001 ($469, Review HERE). Not only do they share so much in common sonically, but they are also tricky f**ks for fit and comfort. Both are prone to causing pain unless you are careful or have just the right sort of ears. The DK3001 has a grand soundstage, with superior height. Its treble is even smoother, but no less airy and open. Mid-range resolution and clarity is not as strong as you find in the IT04, but it sounds even more natural and effortless. DUNU’s bass has less texture, speed, or control, but the tone is so natural and delicious.