Review: HiBy RS2 – R2R To Go

Select comparisons and pairings 

HiBy RS6 ($1,400). As the only other (current) member of the RS family, RS2 bears the closest resemblance to RS6’s DNA. Initially I regarded RS2 as a ‘baby RS6’, but in practice their differences run deeper. For starters, RS6 is twice the size, three times the price, and runs a full Android OS. It has a larger, more vibrant screen, and is made from a solid copper shell. I’d take RS2’s volume button over RS6’s somewhat inadequate top-mounted dial, but other than that, RS6 is visibly and audibly a few steps removed from its baby sibling. 

Sonically I hear the RS6 as more expansive and resolving. It has a warmer tonality too, less aggressive and more refined, although the RS6’s midrange tonality doesn’t balance as well with some IEMs compared to RS2’s more aggressive midrange tuning. RS6 also has a taller midbass bump, but the quality of its bass delivery is a step up from RS2. The use case for RS6 is very different to that of RS2, and as such it’s difficult to compare the two directly. They’d make for a great complementary pair if you’re looking for a set of at home (RS6) and on-the-go (RS2) R2R DAPs for your collection. 

HiBy R5 Gen 2 ($449). Price is really the only similarity between HiBy’s midrange R5 Gen 2 and RS2, since they’re so different in usability and performance. The new R5 sports a slimmed down wireless Android experience, complete with a high-stamina (up to 38 hours playback) battery and the option of Class A amplification, while RS2 is more about ultra-portability combined with musical purity.

Sonically I hear the R5 Gen 2 sounding more ‘digital’ in both its stock and Class A amplification modes. While not quite as glary as some Delta Sigma DACs, its Cirrus DAC is nonetheless very matter-of-fact compared to RS2’s silky R2R tonality. It’s a drier tuning too, although RS2 isn’t quite as organic sounding as it could have been either. Technically the new R5 impresses more out the box, with better resolution (in Class A mode) and a wider stage, but RS2 wins me over with its balance and tonality. Both stay very much in line with the technical performance of their price bracket. 


I used several IEMs with RS2 to try get an idea of where it sits on the spectrum. These ranged in price from $100 to almost $2,000, although to my ears, synergy was more important than price when it comes to choosing the right pairing with your music.

HiBy Hela ($100). I received Hela, HiBy’s newest single dynamic driver IEM, together with RS2, and indeed the two make a very likeable pairing. Hela is tuned with a fair amount of resolution for an entry-level single driver IEM, something that was readily apparent as I listened through my test tracks. It packs a decent punch for a single dynamic too, not quite as impressive as the more sophisticated modern Sennheisers, but enough to satisfy most listeners I would think. The bass bump doesn’t interfere with the mids, and RS2’s rich midrange delivery complemented and improved Hela’s slightly undercooked vocals. If you’re looking for an excellent portable pairing on a budget, RS2 plus Hela is a helluva deal (sorry, I couldn’t resist).

Sennheiser IE600 ($699). There are few DAPs Sennheiser’s safely tuned and highly versatile single dynamic driver IE600 doesn’t like, and RS2 is no exception. It’s a fairly transparent monitor, and as such the combination of natural tonalities is right on the button – if indeed it’s a natural tonality you’re after. There’s no wow factor here, other than everything sounding ‘just right’. I feel IE600 is a great leveler when it comes to choosing a DAP, since it sounds great with everything, and is a definite step-up if you’re ready for a more sophisticated, albeit more costly pairing.  

Campfire Audio Supermoon ($1,500). It’s still early days for me with the Supermoon, but even so this is not a pairing I’m particularly fond of. Supermoon’s is an ultra-clean, rather lean (at times) delivery, and so it needs a DAP that’s warm, full, organic and mellow to balance it out (unless bright, light and shiny is your sound). It’s strange then that despite its R2R credentials, RS2 lacks the necessary authority with Supermoon. It has enough power to drive it (60/100 volume on low gain is plenty), but it pushes mids too far forward for my liking. Supermoon is very, very transparent and also very source picky, and I personally wouldn’t pick the RS2 if Supermoon is your main flame. 

Sony IER-Z1R ($1,800). This is my favourite IEM, and has been for almost a year now, and so I’m intimately familiar with how I like to hear it. Thankfully, Z1R sounds great with RS2. There’s enough control of Z1R’s cavernous sub-bass to satisfy, and even though RS2’s resolution is not optimal, Z1R’s technical chops give it a much-needed lift. RS2’s midrange bump is also something that some listeners will appreciate, since Z1R’s midrange isn’t particularly forward to start with. I’d caution against using Z1R single-ended though, it needs all the power RS2’s balanced port will give it. 

Continue to Closing thoughts



Guy Lerner

Guy Lerner

An avid photographer and writer 'in real life', Guy's passion for music and technology created the perfect storm for his love of portable audio. When he's not playing with the latest and greatest head-fi gear, he prefers to spend time away from the hobby with his two (almost) grown kids and wife in the breathtaking city of Cape Town, and traveling around his native South Africa.


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