The HiBy RS6’s advantage in the sound department is its musicality and atmospheric nature. This is most likely the result of the R2R circuit design. This is a very fluid, organic and musical player that has a life-like sense of realism and naturalness with the classic timbre of copper chassis players. It’s warm, thick and deep sounding.
Based on that impression, one should be selective about pairing it with various IEMs and headphones. The warm nature of the RS6 can be the critical factor when you test its sound quality.
The bass in the RS6 is very strong, deep and impactful, and it can be quite boomy and overwhelming when paired with the wrong IEM. The RS6 goes well with flat, bright and reference-like equipment in this department. However, if you pair it with warm-sounding or bassy gear, the result is not especially desirable. Even so, this is not a big problem for a DAP like RS6. With a little tweak inside the “MSEB” sound adjustment menu, you can perfectly set it to your liking. Yet, these are artificial effects at the end of the day.
The bass reaches very deep, but the decay and quickness of the bass are not on a very high level. However, midbass is nicely executed with great texture. It’s not too fat and doesn’t get in the way of things too much, but retains that unique warmth of the player. I think the overall bass performance of the RS6 is very satisfying, especially for bass lovers in terms of quantity and those who enjoy a warm approach.
You won’t get the quickest bass response with the RS6, but you’ll surely get a very warm and impactful one. So if you’re considering getting the RS6, make sure you set your expectations accordingly. This player has bass, a big one. If you have a flat sounding monitor, you might get the most ideal balance right there. It’s all about matching when it comes to the bass performance of the RS6.
The mid-range has great note thickness and tonality. Again, the warmth of the RS6 continues to put on a show here. It presents a very fluent mid-range, with a good definition and great timbre. I especially liked the presentation of various instruments, particularly acoustic guitar and sax. The musical quality of the RS6 is mesmerizing at times.
The smoothness of the mids is the key factor in the RS6. It doesn’t have the most transparent mid-range, nor the most resolving. But it plays instruments and vocals in a very musical and smooth way. There are players that have better resolution in this area, such as the SE180, but that one doesn’t have the warm timbre of the RS6.
So again, the choices come into play. If your IEM has good clarity and resolution, it will balance out well with the RS6 since you’ll get excellent timbre and tonality, as well as good note weight. The RS6 doesn’t exemplify technicality monsters, it instead speaks for musical DAPs out there. It reminds me of the old Hifiman DAPs; the HM801 and HM601 LE. Similar timbre quality and smoothness.
The treble region is nicely controlled but well extended. Treble sounds very crisp and clear as well. There’s a good balance here with good resolution. It doesn’t sound harsh, but it doesn’t play it too safe either. It has clarity, crispness, and extension with a resolving sound here.
This reminded me of the WM1Z. Not that this one is on the same technical level, but presentation-wise they sound similar. The WM1Z is not reserved when it comes to treble, even though it has a warm sound presentation. The same story is applicable to the RS6. The treble is crispy, sometimes bright and it’s certainly not too shy about it.
So don’t expect a recessed treble just because it is a warm sounding player. The treble is right there with good definition and presence. However, it’s never harsh or piercing. That’s the most important thing. It keeps the treble under control with all of these qualities I mentioned. There’s good transparency here as well.
So overall it’s a very nice treble reproduction with excellent balance and timbre. The treble is not too thin sounding, but not too thick either. It sounds just right and correct. There’s a good resolution here with plenty of detail.