User Experience and Audio Performance

The HiBy R5 (Gen 2) takes some lessons from its Qualcomm chipset by having separate efficiency and performance hardware for audio, too. Given the 4500 mAh battery inside, full 16x MQA folding on the device, and up to 35 hours of playtime, I expected a low-power ESS Sabre DAC. Indeed, HiBy is using a dual ESS ES9219C DAC configuration, which has been used in a few other players and even some LG phones before the company decided it wasn't for them. The ES9219 is an excellent choice with these metrics no matter your stance on MQA as it lays a solid base for the DAP and supports playback at up to DSD 256 and PCM 768 kHz/32-bit high-resolution formats, with an SNR of 130 dB and THD+N under -112 dB. In economy (standard) mode, the DACs can provide up to 1.9 Vrms in high gain off the single-ended output and 3.4 Vrms off the balanced ports, with the latter now rated for 28 hours of playback owing to the higher power consumption. Channel separation is respectively rated for an impressive 62 and 82 dB off the two sections.


The power stage is complex, with HiBy claiming the use of "163 high-precision resistors, 19 Panasonic tantalum POSCAPs, and 4 ELNA electrolytic capacitors to maximally suppress power supply ripple, yielding silky black backgrounds." I can at least attest to the last part, with a completely silent background unless you use exceptionally sensitive IEMs. There is no mention of the output impedance, although the previous R5 iterations were under 1 Ω, so I expect similar here too. There is potential for ultra-low impedance IEMs to display a slight hiss, but only some of the Campfire Audio IEMs did in practice, and they are notorious for hiss with pretty much all sources anyway! There are dual independent crystal oscillators at 45.158 MHz and 49.152 MHz to aid with syncing off the USB encoder, but my attention and yours should go to the onboard Class A amplification circuitry which takes the clean signal from the DAC and ramps things up via a discrete output stage with "4 independent channels of push-pull amplification with 270° conduction angles constructed of discrete componentry, including eight high powered, paired bipolar transistors." In practice, the crossover distortion is eliminated with Class A amplification, allowing for higher output power (2.2/3.9 Vrms) and an even lower THD+N of 0.0006%, down from 0.00022%, but it does become a power hog and reduces battery life to 10 hours on the single-ended and 7 hours on the balanced output. Qualcomm Quick Charge 3.0 reduces charging time to ~1.5 hours from 0–100%, though, which helps a lot.



This is the relative change to the frequency response of three different products—the HIFIMAN HE1000se for a set of planar magnetic headphones, HiBy Lasya to represent wired IEMs, and 1MORE EVO TWS in LDAC wireless mode. The frequency responses of these were separately measured off transparent sources and the HiBy R5 (Gen 2) as the source using the SE and BAL outputs for wired devices, similar to how I do it for all headphones, IEMs, and TWS sets in separate reviews. Any coloration to the tonality off the R5 Gen 2 would show here. Notice the scale of the Y-axis, and the small bumps are within error margins of a perfectly flat line throughout the 20 Hz to 20 kHz range. This was reproducible in individual tests too, with the highest deviations still within +/-1 dB. What it says is that with the HiBy R5 Gen 2 used as the DAC and source, we have a clean signal without any coloring. Based on my experience with many such implementations recently, this is expected from a typical ESS Sabre DAC, and it can come off dry and sterile to many while others appreciate the clarity.

Class A mode does not change the tonality, but adds some impact to the notes, especially in the bass and lower mids. This is easy to test for given the quick toggle function, whereby a blind test confirmed the slight-but-definite improvement, but then brain burn-in kicks in to where economy mode starts to feel just as good. This is especially true with less demanding headphones and earphones, as economy mode has enough clean power to get you jiving to the music first and foremost. Even the SE output can provides ~113 mW at 32 Ω, which can drive the average dynamic driver over-ear headphones to ample loudness, let alone IEMs, where it's more a case of too much power. Balanced output in economy mode pushes the scale up to 320 mW at 32 Ω and ~35 mW at 300 Ω, and it was only with more demanding planar headphones that Class A mode made sense, especially since it makes the DAP fairly warm to the touch if held without the case. I had to get an XLR to 4.4 mm balanced adapter to try this out, but the HE1000se in this configuration gets a massive 435 mW of power—enough to exceed 120 dB, which is deafening. Of course, all these values are in high gain, so try out low gain or low volume and take care of your ears, so you can listen to your favorite audio files for long periods of time.


I wanted to give a special mention to the Bluetooth capabilities. We saw before that the dated Qualcomm chipset restricts the R5 Gen 2 to Bluetooth 4.2; however, HiBy has done a good job with codec support in the form of AAC,SBS, aptX, aptX HD, and LDAC, which all tested successfully. But then there's a special fifth codec called Ultra Audio Transmission (UAT) HiBy developed to support up to a transmission sample rate of 192 kHz at up to 1.2 Mbps Bluetooth bandwidth, which is unheard of! Equally unheard of outside of HiBy are the TWS sets supporting this codec, as those are rarely seen in the consumer market. Hopefully, this shout-out raises awareness of the company's tech offerings, as there is a lot to discover and appreciate.