In my R6 review I considered this to be the most important section due to high (10 ohm) output impedance of the original R6 DAP which affected the sound of many multi-BA IEMs (not all of them). Plus, the sound sig of the DAP will have a direct impact on the sound of your IEMs/headphones. R6 Pro output impedance is low now, but its sound sig also changed. Thus, I decided to revisit many of these pair ups again. For the reference, I copied my notes from R6 review (including iEMatch comments) and added new R6 Pro pair up impressions. With an exception of EL8C, everything was connected balanced.
64 Audio U18t.
R6: Talking about night’n’day difference, that’s how I can describe the sound of these iems with and without iEMatch. Without, you have a very mid-forward bright signature with a neutral flat bass. Once iEMatch added in series, U18t transforms with a deep textured sub-bass rumble and fast mid-bass punch with a slightly boosted quantity, neutral lower mids, natural micro-detailed upper mids, and crisp airy extended treble. This is not even a question, if you want to use U/A18t with R6, iEMatch is a necessity.
R6Pro: takes another leap forward when it comes to sound changes. Here, the sound is warmer, smoother, with a more musical fuller body tonality. The bass goes deeper with more sub-bass rumble and has more analog texture, lower mids are noticeably fuller in body and upper mids are more organic in tonality, treble is a little smoother as well. In case of R6 vs R6 w/iEMatch, the change in sound was driven by the change in impedance. But going from R6 w/iEMatch to R6Pro – it almost sounds like a new signature. One thing to note, in case of U18t due to its higher sensitivity, R6Pro in low gain has a blacker background while in high gain there is a faint hissing. Switching to 3.5mm reduces hissing even further.
64 Audio Fourte.
R6: This is the one pair up so far where the synergy between a dap and iem wasn’t there, regardless of iEMatch or not. Adding this adapter does takes an edge off the upper mids/treble which could be a little too vivid for some, and regardless of the adapter the bass was still very accurate and with a nice sub-bass rumble and mid-bass punch, though both rather polite in quantity. But the main problem here were the mids which sounded a bit muffled to my ears, not the same as other DAPs. For me personally, this is not a good pair up.
R6Pro: Added more weight to the lower end, scaling up the quantity of both sub-bass and mid-bass. I also hear more body in lower mids, but upper mids and treble are still crisp and a bit too revealing for my taste. Interestingly enough while mids sounded a bit muffled with R6, in R6Pro even with a little more body and a bit smoother sound, I didn’t hear that effect. Also, a little bit of hissing is present, reduced by going to low gain or switching to 3.5mm output.
Campfire Audio Andromeda.
R6: iEMatch is definitely a must-have because without it the sound has a very neutral bass with a rather forward upper mids and splashy treble and a very noticeable sibilance, which I usually don’t hear from Andro. Once iEMatch added, it transforms into the sound I’m used to while listening with other sources – you get a fast mid-bass and a nice sub-bass extension which shines more with quality rather than quantity, neutral mids, detailed upper mids with a little brighter and more revealing tonality, and crisp airy treble. iEMatch definitely brings Andro back to its fun signature.
R6Pro: Adds more body and more warmth to the sound, mostly in lower end where the bass is thicker and has more analog texture, and also in lower mids which are thicker, adding more body to the sound which results in overall mids being more organic, smoother, warmer. Treble is the same here. Due to its high sensitivity and high output power of R6Pro, Andro has more hissing here. Applying iEMatch removed all the hissing and made bass a little faster, while also reduced some thickness in lower mids, maintaining the same natural smoother tonality but with more transparency.
Empire Ears Legend X.
R6: The clever crossover design of this hybrid reassures there is no need to worry about iEMatch because with or without it the sound is the same. You get a powerful L-shaped signature with a deep impactful sub-bass rumble and elevated mid-bass slam, with bass being well controlled despite being a force of nature that you feel in your chest. Mids are very natural and detailed, not really pushed back, but being more in a background due to elevated bass, and the same with a treble which is well defined and with a polite crisp and airiness. This is a basshead audiophile iem and it hits hard with a bass. Actually, even harder in comparison to other dap pair ups.
R6Pro: The sound is more balanced and the mids that were pushed more into a background now have a little more forward presentation, a much better balance next to an elevated bass. Treble is the same, but I do hear bass having a slight reduction in “booming” impact. The sound sig is still L-shaped, but overall sound is more balanced. Still, no need for iEMatch in either case.
R6: Low impedance multi-BA, you can safely guess iEMatch will be a welcome addition here. Direct connection gives you a slightly mid-forward signature since bass is more neutral and upper mids/treble are elevated. With iEMatch, the sound is balanced with a nice sub-bass rumble and punchy well controlled mid-bass, not too fast or too slow, neutral lower mids, natural detailed upper mids, and a crisp and well controlled treble. Very enjoyable pair-up, as long as you keep iEMatch handy.
R6Pro: With low impedance output, you no longer have to worry about iEMatch here, the sound is balanced, smooth, with fuller body, yet still detailed. Vocals do sound a little thicker now, to the point where I actually enjoyed the pair up with R6/iEMatch better. Thus, overall R6Pro pair up with W80 wasn’t my favorite.
R6: The sound is balanced with a nice deep sub-bass extension, great mid-bass impact, very natural detailed mids, and a nice crisp airy treble. iEMatch reduces some of the treble definition, taking away a bit of sparkle and airiness. Wide soundstage. I prefer a direct pair up here.
R6Pro: Connected directly to R6Pro I hear more sub-bass rumble and a little stronger mid-bass punch, with mids still being quite detailed but just a touch smoother now. With treble, it’s not exactly like direct connection to R6, but it’s close enough and much better than with iEMatch since sparkle and airiness are back.
R6: Above average soundstage width with more depth. The sound is brighter in tonality in comparison to other pair ups, PM3 sound can get easily congested with some DAPs, here the sound was closer to neutral with a more revealing tonality, still smooth and a little laid back, not very layered or with improved separation. Warm sub-bass extension with a slightly elevated mid-bass – bass is typical of PM3, being slower, not as articulate, but it has a better control in comparison to pair ups with other DAPs where bass usually spills into lower mids. Here, lower mids do have full body, but they are not muddy or congested. Upper mids are smooth and detailed, while treble has a nice well-defined sparkle.
R6Pro: The sound is warmer, smoother, still quite detailed, and the signature is balanced, and overall, I hear the sound as being a little more coherent and more natural.
R6: wide/deep soundstage and a very fast sound, typical of planar magnetic driver performance. Bass is very neutral, being all about quality rather than quantity when it comes to sub-bass extension and mid-bass punch. Lower mids are lean, and the big emphasis here is on upper mids and treble. Mids are detailed, actually down to micro-detailed level, but they are also cold and more analytical. And the treble is a little too sharp, making the sound more revealing and less natural. It wasn’t my cup of tea, but I’m glad to report there wasn’t metallic sheen in the sound, like I find in some other pair ups.
R6Pro: The sound change wasn’t too drastic, and I suspect that EL8C might benefit more from higher output power in this pair up, but I only have SE cable. Tonality got just a little bit warmer, but treble is still a bit too distracting.
Beyerdynamic T5p 2nd.
R6: Wide/deep soundstage, almost on a holographic level, and the overall sound is very balanced, with a natural neutral-revealing tonality. Sub-bass has a nice deep extension, but the quantity of the rumble is a little north of neutral. Mid-bass has a nice fast punch, with an overall bass being very articulate, layered and well controlled. This leads to a more neutral lower mids and micro-detailed upper mids, but with a more natural detailed tonality. Treble is crisp and airy, gives a very good definition to a sound.
R6Pro: Scales up the performance of T2p2. It’s not a drastic change, but a rather noticeable refinement of bass being tighter, a little faster, even more controlled. Mids get a little more body but still remain very detailed and quite natural in tonality. Upper mids are not as micro-detailed, but more organic. Treble is the same. I guess extra power kick of Pro gives these Tesla drivers a little better and more natural definition. Very good pair up.
As you probably noticed, I didn’t talk about GUI since it’s the same as in R6, the standard Android interface updated to 8.1 using a default HibyMusic app many already familiar with. And with access to Google Play, you can download any of your other favorite music playback apps. I also didn’t include DAP comparisons since the focus here was more on R6 vs R6Pro, and I already covered R6Pro comparison in my latest DAP reviews. Besides, the technical sound performance of many latest flagship DAPs is starting to get close. I mean, there is still a difference in sound signature (dictated by DAC and amp chips selections), and you have variation in output power, battery life, processor speed, internal and expandable storage, etc. All that should be considered under Pros/Cons when thinking about your next DAP purchase.
If you are deciding to upgrade from R6 and looking into R6Pro, there are definitely advantages in higher output power (if you need to drive more demanding headphones), 4.4mm balanced output (a new standard with many latest upper tier DAPs), lower output impedance (though you might still need to use iEMatch with very sensitive IEMs). The Android performance is still very fast and relevant. And one important advantage, Hiby is the company which used to take care of everyone else’s fw/sw, so you know you can count on a solid support and frequent updates and fixes.
But in general, with so many quality DAPs flooding the market now and a wide gap in pricing, sooner or later many of these manufacturers will have to figure out the way how to reinvent the wheel beyond just the use of the latest DACs or the faster processors. Can’t wait to see what Hiby is going to come up with next!