The XBA-6in1 are indeed an amazing upgrade over the previous 4in1. They fixed the pierce and the added some much needed warmth to the sound as a whole. The sub-bass is deep, yet the mids remain loud and forward. Thanks to their excellent balancing - the vocals aren't shouty and you won't have to boost the volume to hear the bass. Perhaps their closest competitors are the LKER i8, both being unashamedly loud and mid-forward with deep rumbling bass response, but XBA-6in1 has the upper hand when it comes to longevity thanks to the replaceable cable (which is also of good quality).
Sound signature: Mid-centric
Amazingly clear audio quality with mid-centric sound signature.
Powerful and well-balanced mid-bass with deep, punchy sub-bass.
Super loud. Can be driven even by low-powered sources.
Sturdy, highly durable build quality.
Standard MMCX connectors which makes customizing accessible and extends the lifespan of the earphones.
Unoriginal design, to say the least...
Very basic package contents.
Quite expensive, compared to most budget earphones.
It is no secret that XBA-6in1's design was highly inspired by Sony's XBA series. Personally, I'm not a huge fan of that design. I think it's weird and has nothing to do with human ear anatomy. Nevertheless, I had no issues wearing these cable straight down. Wearing them over-the-ear was a no-go for me.
Lows / Bass
Deep and pounding and very well-balanced. I've yet to experience any leakage of bass into the mids. This bass adapts to anything from rock to electronic dance music, it's pure fun to listen to. The mid-bass is a bit more prominent than 4in1's mid-bass which warms up the whole sound and gives it some much needed body and volume.
Mids / Vocals
Very forward mids, but their accurate reproduction makes the sound quite impressive rather than fatiquing. Thanks to the well balanced sound signature, you won't feel uncomfortable listening to vocals even on lower-than-average volume. Voices are warm but not bloated, guitars are crunchy and upfront. Absolutely incredible results.
Highs / Treble
While TinAudio T2's highs seem to be more crisp, but also prone to pierce sometimes, the XBA-6in1 retain clear and bright highs without introducing as much pierce or sibilance on the vocals, but they are still quite aggressive and peaky. They are tonally more on the natural side, compared to T2 and are probably one of the best all-rounders on the budget market right now, but those who are looking for a balanced experience might get a bit overwhelmed.