Sound Impressions
The following sound impressions of the HiBy R8 II were completed using a mix of the Unique Melody Multiverse Mentor, (Custom format), FiR Audio’s Radon 6, and the Noble Audio Ronin.
Summary
The R8 II is quite a contrast to the RS8 and the RS6 and a big upgrade on the R8’s performance. It teases out a bold and very exciting sound signature from my tested IEM pairings.
The switch to a delta-sigma and away from R-2R also brings with it a polished ‘perfect’ tonal quality as I like to describe it. There is less warmth or analog overtones and more of a cleaner ‘pacy’ neutral to natural sound, at least in comparison to the RS8 and RS6.
I would never describe the R8 II presentation as a ‘reference’ though. The energy and PRaT from a pronounced bass tuning give it a ‘joyful’ character, a more aggressive one than what I have previously heard from HiBy DAPs at this level.
The dynamics from the lows of the R8 II shine on every single pairing I tried. Even IEMs with no dynamic drivers such as the Multiverse Mentor had tons of low-end authority, especially with the Class AB mode.
Class A has a similar fullness on the lows but not quite the same energy and slam as Class AB so if you feel the excitement is a bit too much for the latter you can tone it down a bit with the smoother former.
I found Class A works beautifully for IEMs such as the Radon 6 whose Kinetic bass dynamic driver really shifted some serious air with Class AB but slightly less refined through the mids and highs.
It’s not all about the bass. The R8 II has an impressively black background with a very open and more forward-sounding midrange and vocal presence compared to the older R-Series DAPs.
Some noticeable upper-treble extension also creates a strong perception of height and space, especially with tall-sounding IEMs such as the Ronin.
Coloration
HiBy has teased out a very balanced tonal quality with the R8 II. It is not as ‘organic’, analog, or euphonic as the R-2R implementations and carries a little less comparative warmth but it also does a really good job of preventing my IEMs from sounding digital, dry, or steely on the highs.
The tonal coloration has a type of presentation that I associate more with a delta-sigma-type sound. I had referred to it as ‘polished sounding’ in my summary which means there is very little roughness on the edges with a slight leading edge emphasis and shorter levels of decay compared to the RS8 or RS6.
Meaty? Yes, but not quite as dense and rich in note texture as the RS8. However, in return, you get impressive precision, clarity, and a lot of micro-detail delivered in a rapier-like fashion from capable IEMs.
Lower-register note fundamentals delivered by the R8 are mesmerizing and for me one of the standout aspects of how the R8 II influences your head gear’s coloration.
It is less about how full-sounding it is or how much warmth there is but rather the impact, the definition, and the speed of the delivery of those lower register notes.
More so for Class AB also which is where you want to be to hear the R8 II at its most energetic. Class A adds more subtle refinement, sounding a little smoother and richer for vocals and reducing Class AB’s higher levels of contrast on percussion passages.
Dynamics & Staging
This is where I feel there is a clear night and day difference between the stocking tuning of the R8 II compared to the original R8.
The immediacy of the presentation, the improved depth and wider stereo field, as well as a better level of dynamic range, are all very obvious. You also get a much blacker background, better attention to micro-detail, with a more open and forward midrange to match that high-energy bass performance.
The icing on the cake is the upper-treble extension which is slightly emphasized without bearing down too much giving a very nice perception of height and space from the R8 II with big staging IEMs like the Ronin and the Multiverse Mentor.
With the R8 I had this subconscious need to always up the volume a bit more to see if it would flesh out a bit more wallop from the performance. Not so with the R8 II whose soundstage is more impactful and engaging.
Particularly so with the mids and vocal presence which are also more forward-sounding than both the R8 and the RS8. I tend to refer to the RS8 mids as relatively neutral in their imaging and more so now when AB’ing the R8 II with matching IEMs.
For RS8 owners, I still feel the RS8 offers a bit more sub-bass presence so when you are comparing the two on Turbo Mode the flagship should come across as the weightier of the two devices.
Turbo Mode
I would advise keeping Turbo Mode on period unless you find the performance response in the lows to be too aggressive for your chosen headphone or IEM. I do the same on the RS8 also so it is not just an R8 II thing.
A few reasons but overall, it’s a far more dynamic presentation compared to the slightly softer ‘play within yourself’ non-Turbo performance. You do feel the soundstage pulling away from you in non-Turbo mode with bass lacking a bit of drive and authority in the process.
That is the same for both sensitive IEM and more demanding headphones so it is not simply about more power for higher loads but the quality of that power being driven to the output.
An excellent example was the 64 Audio Volur (M15 filter) balanced output pairing which sounded ok without Turbo Mode but perhaps lacked a bit of engaging bite with the R8 II.
The mids sounded very neutral and lacking in vibrancy compared to when Turbo mode was switched on not to mention the extension and presence in the highs became a lot more energetic. You could describe it as having a curtain being lifted from the Volur’s performance.
Plugins
Tucked away in the Audio settings menu is a section called Plugins which operates on a system-wide basis.
These should not be confused with regular digital filters you might find with off-the-shelf DAC chipsets as these make substantive changes to many aspects of the R8 II presentation.
Which plugin and which aspect will depend on the gear you are pairing the device to as well as your personal preference since some of the plugins have some in-depth layers of control.
There are 5 available plugins for the R8 II and the two most transformative and useful plugins are Sound Field and DRX10K Dynamics.
Sound Field
The Sound Field plugin shapes and extends the overall width of the soundstage and is excellent for IEMs that can deliver impressive staging depth.
For example, the UM Multiverse Mentor is a big sounding monitor and more so with the Sound Field turned on with incredible width and clarity on both ends. It’s addictive with airy ethereal genres but I would also caution it’s less ideal in terms of reverb control the more you pump up the staging width.
Set the plugin value too high and it can mess with vocal presence, harden the upper mids and generally create too much hall-like reverb in the process. The sweet spot for supreme separation is just a little to the right of the slider’s center.
DRX10K Dynamics
DRX10K Dynamics looks like a set of tone controls with additional gain functionality but what it does is tease out a desired level of dynamics in specific FR areas to counter perceived compression in recordings.
You can control the bass presence, mids, and/or treble with individual sliders offering up to a potential 10 dB gain swing in 0.5 dB increments.
The stock DRX10K Dynamics settings, (+0.7,0.0,+0.4,-6.0), were not ideal for my IEM choices. The gain was quite a bit reduced with the bass overpowering. It produced a very rounded dark tonal quality to the likes of the UM Multiverse Mentor.
However, you do not have to stick with that setting. You can mess around to create some very unique presentations. For example, returning to the Multiverse Mentor again which has a somewhat relaxed midrange. I wanted to try and really up the vocal dynamics to a crazy level to see what would happen.
Here I pushed the mids to +0.6, the treble to +0.6, and dropped the bass slightly to +0.5. It isolated the vocal performances perfectly but at the cost of narrowing the front of the stage and reducing the backing instruments’ presence.
For such a jump you also have to be careful with lowering gain to prevent clipping during dynamic peaks in the tracks so I would suggest keeping it at least 3-4 dB below zero.
There is always a trade-off with these applications in terms of potential for reverb, attenuation, and staging quirks. I suggest moderation, to begin with.
However, the depth of the potential with its ability to be used in combination with other plugins such as Sound Field as well as MSEB produces a very intriguing level of sound customization.
Synergy
Noise Floor
The R8 II probably has the blackest background and IEM-friendliest default gain level of any HiBy DAP I have reviewed thus far.
We are a long way from the hit-and-miss noise floor of the R8 with perfect silence coming from the likes of the Campfire Audio Andromeda 2020 and the Solaris.
Heck, I would even plug in the hyper-sensitive Empire Ears Zeus into the R8 II and be reasonably confident that the gain level would not be too bothersome from its 4.4mm balanced output. That is rare considering just how sensitive these IEMs are to background hiss with virtually any amplification.
The channel balancing from the R8 II’s volume rocker is excellent also. Granted, I get a vibe that going from 1 to zero on the rocker feels somewhat abrupt rather than a natural attenuation but the results speak for themselves with perfect silence on zero and no channel imbalance step by step upwards.
The R8 II output impedance is 1Ω from both PO outputs so there are no concerns regarding impedance skew or using higher impedance to create a false impression of a low-noise floor.
I had noted in the RS8 review synergy section that this was a DAP with a very good noise floor and gain level also but it would struggle a little more if the gain setting was on high with sensitive IEMs. The R8 II does not have that problem, it remains deathly quiet on all gain levels even with Turbo mode turned on.
IEM Pairings
I tested 5 IEMs with the R8 II in Turbo mode, balanced, and with no DSP. This included the UM Multiverse Mentor, the JH Audio Jolene, FiR Audio’s Radon 6, Noble’s Ronin, and the 64 Audio Volur.
Each delivered a superb black background with excellent resolution. This is an aspect that continually impressed me with the R8 II pairings. Particularly with IEMs that can project a huge soundstage such as the Multiverse Mentor.
However, I did come away with some tonal preferences for the pairing lineup. The high-energy, punchy, and precise nature of the R8 II presentation worked a charm with highly resolving IEMs that biased more to a natural or slightly warm side.
IEMs such as the Unique Melody Multiverse Mentor sounded immaculate and expansive, shining a light on the excellent levels of micro-detail that the R8 II can offer.
The Volur captured the bass impact and energy of the R8 II. It is not as weighty as the RS8 pairing but it sounded punchier and more rapier-like.
The JH Audio Jolene is another bass performer, especially with the bass boost module. It is, however, darker through the mids and lower treble in its stock tuning.
The excellent extension on the R8 II highs combined with the Sound Field plugin opens up the Jolene beautifully, introducing more air and bite with some additional focus on vocal presence.
You get some powerful lows of the Radon 6 but at times I preferred the RS8 or the Cayin N7 over the R8 II for a richer or more analog mids sound.
The R8 II sounded comparatively cooler-toned over the same range for some percussion passages though a gentle -dB PEQ drop around 8-10k and using Class A can help soften it to very acceptable levels.
Headphone Pairings
The R8 II has slightly less power for more demanding headphones compared to the RS8 at 710mW into a 32Ω compared to 780mW but for casual use, the difference is not huge.
It’s only really when you start comparing 1W and above amplification output that you start to see some differences with headphones that are generally more comfortable receiving more power.
A good example is the 80Ω and 104 dB SPL / 1mW @ 1kHz rated Focal Utopia 2022. There is no problem with gain levels and certainly on a high gain the Utopia sits comfortably below any maximum volume setting from the R8 II.
However, compared to something like the 1.3W (32Ω) capable Shanling H7 you do feel there is more headroom when compared to the R8 II. Especially with the Utopia 2022’s slightly narrower soundstage shape where the H7 did better in teasing out a bit more width.
For planar headphones, I found the 4.4mm output performance more than acceptable for the likes of the Dan Clark Audio E3. Ideally, you want 1W plus for this headphone to sound optimal but with Turbo Mode turned on I felt the overall dynamics and staging filling capability of the R8 II to do much better than expected.
For more sensitive headphones, the R8 II will have enough in the tank with Turbo Mode turned on. Headphones such as the Meze Empyrean II sounded lively and clean with good dynamics using a high gain balanced output pairing.
