Pros:

• Cool design

• Flagship level configuration

• Class A amplification

• Fast operation

• Android 12

• Systemwide parametric EQ

• Very neutral and natural sound

Cons:

• Battery life

• Low power output

• Side buttons are hard to feel and press with the leather case on.

• Lack of volume wheel

R6 Pro II is, as the name implies, the second iteration of the improved Pro version of the R6 line of Digital Audio Players from Hiby. Although I have known and followed Hiby as a company, R6 Pro II is the first of their products I have actually used. Retailing at 749 USD, this DAP has some impressive specs to boast about.

Disclaimers​

I bought R6 Pro II with my own money from a friend pre-used so, of course I didn’t pay the full price if that matters. I have been using the device for some time as my personal unit, therefore review includes my own long term user experience as well. As I always say, everyone is biased one way or another so take everything you read with a grain of salt. Also I will try to be more concise and to the point in my reviews from now on without worrying about the word count etc. If you have any questions, please ask me in the comments and I will try to answer them to the best of my abilities.

About Hiby​

Hiby was founded in 2011 according to their website and has even more experience in the audio field apparently. They are mostly known for their Digital Audio Players but they also make DAC/Amps and earphones. However, what makes Hiby different from other manufacturers is their expertise in software. Their UIs, apps and connection protocol Hiby Link are used by even other brands.

Packaging of R6 Pro II​

R6 Pro II comes with a rather modest packaging, still it doesn’t feel like missing anything. A leather protective case, spare screen and back glass protectors, a rather thick USB-C to USB-C cable and a USB-C to USB-A adapter is included in the package. Leather case feels sturdy and premium enough and has a great design feature that stretches and closes when the DAP is slid inside. After the loose DX300 case I used for a long time, it is a very welcome change.

Hardware of R6 Pro II​

R6 Pro II is a hefty device. In fact it’s heftier than I first thought it would be, definitely more in line with +1k devices. It has a unique asymmetrical wavy design but not as esoteric as Astell&Kern devices. R6 Pro II comes in two colors: Purple and black. Purple comes with a purple case and black comes with a gray case. Honestly I would have liked to have the purple one instead.

Inside, the device used Asai Kasei’s latest DAC chip AK4499EX in dual formation along with their AK4191EQ delta-sigma modulator. Companies like to promote this modulator as another DAC chip but it really isn’t and if I’m not mistaken this modulator was embedded to older chips but in the latest AK4499EX they separated it from the DAC chip instead. Still these chips are flagships of the company and having them in a DAP that’s sold for 749 USD is quite a feat.

R6 Pro II runs Qualcomm’s Snapdragon 665 processor. While it’s not a flagship or the latest processor on the market, due to batch limitations, it was probably the best one they could offer. However I'm pretty sure it's the fastest processor that’s used in a DAP currently on the market. I had no problem with the operation of the device. It’s always smooth and responsive. Even one of my friends commented that it was faster than his phone.

Device has 4 GBs of RAM which is again enough for the intended use case and 64 GBs of internal storage. You can also add a micro SD card to increase the storage up to 2TBs for your music.

R6 Pro II has an independent amplification circuitry that can provide both class A amplification with dual OPA1652 op amps and class AB amplification. I will describe the differences later in its own section.

5.9” FHD+ screen with minimum bezel thickness gives R6 Pro II a sleek look but Hiby decided to feed all this hardware with 5000 mAh battery which yields suboptimal listening times.

Lastly R6 Pro II supports the usual wireless and wired connectivity options, namely WiFi, Bluetooth 5.0, USB and Coaxial through USB-C output. Analog outputs include 3.5 mm single ended and 4.4 mm balanced. Line outs and phone outs are separated. Device also supports DLNA, Airplay and their own Hiby Link protocols as well as Hiby Cast remote control. It can render X16 MQA too, if that’s important for you. I’m pretty sure there are others I forgot to mention.

So all of these yields to virtually no distortion and noise. Battery life isn’t the best, I got 5 hours and 45 minutes of playing time with streaming in class A mode, low gain and balanced output at volume 50/100 which is louder than my usual listening level, with minimum screen usage. Website says R6 Pro II plays for 5 hours in balanced class A mode so info is more than real. It’s mostly enough for me but competitors offer more so there is that. Class A mode works slightly warm which is expected.

Amplification section isn’t very powerful but should be enough for almost all IEMs and a lot of headphones out there. Max single ended power output is 125 mW and balanced power output is 383 mW.

Software and UI​

R6 Pro II uses an open Android 12.0 which means you can download any 3rd party apps you want and it should get app updates for quite a while. While Android 14 is out, 12.0 is the newest version among the current DAPs on the market if I’m not mistaken. Hiby Music comes pre-installed as the default music player and I didn’t need to use any other music app since I mostly stream my music.

UI is customized by Hiby for the intended use case. It is not too different from the usual Android experience but changing audio controls like adjusting gain and amplification type is especially very easy.

Hiby’s own MSEB (Mage Sound 8-ball Tuning) is an EQ based easy sound adjustment mechanism. If using EQ is intimidating for you, playing with MSEB can ease you into it. I think it’s a great feature. Here is the list that shows how each choice affects the sound:

1 -- Overall Temperature is a tilt of the whole line towards treble (cool) or bass (warm)
2 -- Bass extension 70Hz and below
3 -- Bass texture 100Hz (medium)
4 -- Note thickness 200Hz (wide)
5 -- Vocals 650Hz (very wide)
6 -- Female overtones 3kHz (tight)
7 -- Sibilance LF 5.8kHz (medium)
8 -- Sibilance HF 9.2kHz (medium)
9 -- Impulse response 7.5kHz (very wide)
10 - Air 10kHz sloped all the way to 20kHz

Other than that Hiby added Systemwide Parametric EQ to P6 Pro II along with some of their other DAPs with the latest updates. Actually groundwork was always there, MSEB used it after all, but they decided to give the freedom of choice to us. It has 9 bands and all the filters, not just peak filters. I tried different use cases and it worked with 3rd party apps and also digital out through USB. Looks like Hiby wants me to sell my RME Adi-2 DAC FS.

Sound of Hiby R6 Pro II​

I don’t like describing the sound of the source gears with frequency response terms but I don’t really know a better way either. In the case of the R6 Pro II, in one word, it sounds focused. First thing I noticed when I started listening to it was how focused it was, especially the midrange. No region in frequency response was emphasized but if I were to name one highlighted area, it was the midrange.

The Midrange of the R6 Pro II is clean, crisp and sharp. Bass is neutral, just how I like it. I know we mostly judge the quality of a source gear by how it handles the bass and believe me it handles it well, especially in the class A mode but doesn’t particularly emphasize or highlight it. Treble is devoid of any digital glare or sharpness. So while I wouldn’t call R6 Pro II a warm source, if neutral normally has this kind of quirks for you, I guess you can call R6 Pro II a little warm.

R6 Pro II is very resolving, more resolving than its peers. Its staging capabilities are also above average and the focus I kept rambling about makes imaging and layering especially sharp and precise. Timbre is very natural too. As usual comparisons should shed more light to what I mean.

Class A vs. Class AB​

• Biggest difference is in the bass notes. Class A is more incisive in its attack. It also sounds bolder and more confident, AB, compared to that is softer.

• Class A has sharper and more focused imaging and separation. It makes Class A resolve the nuances easier too. Class A also might be slightly more spacious but it’s hard to tell.

Although Class A is definitely the way to go for me, depending on the situation you can choose to use Class AB too, to make the battery last longer or to have a more relaxing listening session.

R6 Pro II vs. Fiio M11 Plus LTD​

When I had the M11 Plus I briefly compared the two and sold the M11 Plus in the end. My findings were as follows.

• Bass was more emphasized on Fiio with more heft and body to it.

• Timbre was the most apparent difference between the two, R6 Pro II being more natural, especially the midrange on the R6 Pro II sounds better with more focus.

• Imaging was sharper on R6 Pro II and staging was more enveloping.

• Other than sound differences, R6 Pro II uses a newer processor, OS and DAC chip. With the latest update R6 Pro II got systemwide Parametric EQ too.

Desktop Rig (Monolith Liquid Platinum DAC and Amp Section of Yulong Da-art Aurora)​

• Desktop Rig has more handling power on tap and bass is even more authoritative.

• Desktop Rig also has better staging.

• R6 Pro II is smoother and more controlled in the treble.

• Desktop Rig is more resolving and has better layering and separation capabilities.

All in all my desktop rig is more lively but R6 Pro II smooth and controlled.

Conclusion​

Hiby R6 Pro II was a device I have been very interested in since it was announced. I “degraded” from DX300 and never looked back. I also had FiiO M11 Plus LTD for a short while but didn’t feel any inclination to keep it. That’s how much I like my R6 Pro II. I knew what I was getting into. Yes power output is lower than other DAPs in its price range but I mostly use IEMs outside so it wasn’t a problem. Also I can only listen to music for a couple of hours at the office so battery life didn’t bother me too much either. Sound quality, the parts that have been used, futureproof OS and Parametric EQ already make this device a value proposition that’s too hard to pass.