The dynamic driver gives you the kick and rumble if the recording has them, but it’s not like some other hybrid monitors that have incredible punch and rumble. The Fusion keeps the low frequencies in a tremendous control. This is one of the best implementations of the dynamic drivers I’ve experienced, if not the best.
Mostly with hybrid IEMs, the sub-bass is the dominant area whereas the mid-bass is a bit recessed. The Fusion, however, gives one of the most well-balanced and cohesive bass reproductions I’ve heard to this date. If I’ve told you that this is full BA IEM in a blind test, I doubt that you’d notice it. Lows are very close to the reference sound, and comparable to my studio speakers.
At the same time, the lows have good texture when needed with great resolution and perfect control. From this perspective, I can say that the Fusion stays faithful to the recording and the source. It doesn’t add anything excessive. That may not be your cup of tea if you seek a very impressive bass impact, and there are IEMs out there that surely give a more impressive bass presentation in terms of quantity.
Lows are very fast too, and there aren’t any problems with fast-paced songs. It has excellent decay and recovery.
This is the area that the Fusion shows its musicality and great tonality. In mids, you can realize that this is not a boringly flat monitor. The transparency in this area is also exceptional. The timbre of instruments is very nice, and it has a very slight amount of warmth to make it musical instead of analytical.
The mid-bass body is not too obvious at first listen, but you realize it’s there after some time. That is one of the reasons for the unimpressive presentation at first. The Fusion doesn’t try to impress from the get-go. When you spend more time with it, you start to appreciate the incredible balance and coherency.
The mids are in excellent harmony with bass and treble. Tonality is very life-like as well. The note thickness is also there but not too much like some other IEMs. However, it’s not too thin either. It is all about balance with the Fusion. The resolution is also very close to the TOTL level.
In my opinion, the lower mids could’ve been a bit warmer with more thickness along the way to give an even better foundation to the mids. That would make a perfect presentation for me, but it’s already very good as it is.
Treble is outstanding with the ItsFit Lab Fusion. That magnetostatic driver shows it wonders there, especially with treble-rich songs. Highs are apparent, very resolving, and sometimes bright in a good way. Despite its strong treble reproduction, this area is mostly very sleek and clear from any possible sibilance.
The treble performance may vary with the universal version because of the fit and tip selection. But with the custom one, the treble has a great amount of air, and the extension is very impressive. This part is very sparkling, lively, and rich with the Fusion. It wouldn’t be wrong to say that this area is the highlight of this CIEM.
The treble has great separation and articulation as well. Timbre is nicely done once again with a great balance between thickness – thinness. There’s also a great amount of detail and transparency in this part. Itsfit Lab surely has done a wonderful job with this driver. I couldn’t find any flaws to criticize in this area.
The review ends on PAGE 4 with technical performance and comparisons.