Well known for their amplifiers and digital audio players, iBasso have only recently ventured into headphone territory. The iBasso SR2 headphones, which supersede the originally released SR1 headphones, feature an all-new design with a higher quality feel and open-back implementation. Unlike the limited-edition SR1, iBasso plan to make the SR2 abundant in quantity. The $569 headphones incorporate dynamic drivers in a silicone suspension with Tesla magnetic flux technology and bio-cellulose dome diaphragms to provide a high-fidelity sound.
With an impedance of 24 Ohms and sensitivity of 108 dB/mW, the iBasso SR2 headphones are easy to drive. This makes it a versatile transducer which can be driven from a smartphone, laptop or digital audio player without the need for a dedicated amplifier.
The SR2 headphones arrive in a three-tone silver box bearing a cut-out graphic on the front. Overall, the packaging is very polished and professional looking. The rest of the key specifications and details can be found on the rear of the outer box. Inside, a sturdy black carry case houses the SR2 headphones along with the cables in a secured mesh pocket. Also included is a start guide, warranty card and an extra set of ear pads with larger perforation.
The Build & Design
The SR2 headphone improves on the industrial-looking design of the original SR1 headphones. The aesthetics is rather reminiscent of the HiFiMAN HE-400S with the silver outer rims, honeycomb housings and black headbands. However, in my opinion, the SR2 headphones provide a further refined look with the curvilinear outer rim, plump earpads and robust screws. It is also nice to see that iBasso have opted for minimal branding with ‘designed by iBasso Audio’ displayed in small font on the outer housing.
Build quality is exceptional with the swivel mechanisms and rotation of the housings working flawlessly. The well-crafted aluminum outer rings together with the leather headband are an example of the high-quality components iBasso have decided to implement. Perhaps the only improvement could be the sliding mechanism which does feel a bit stiff to adjust.
The iBasso SR2 utilizes the concept of magnetic flux density in a ‘Tesla magnetic circuitry’ to improve efficiency and micro-dynamism. Compared to conventional transducers, the increased intensity of the magnetic field provides greater flux to drive the diaphragm easily.
This concept is not new and can be seen in Beyerdynamic and Fostex headphones. However, equipping with this technology with silicone suspension drivers is certainly new. In fact, the original SR1 headphones were the world’s first to combine the use of Tesla Magnetic flux with silicone suspension. The aim being to improve dynamic range throughout as well as transient response.
Finally, the SR2 features a bio-cellulose dome within its diaphragm structure. As with beryllium, bio-cellulose has high stiffness to weight ratio and was likely chosen for its ability to reduce total harmonic distortion.
With the plump pleather ear-pads and evenly distributed pressure from the headbands, the SR2 headphones are very comfortable. Clamping force is a bit on the higher side of normal but the deep and angled ear pads does offset this pressure. At 395g, the SR2 manages to shave off 25g compared to the SR1 and does not feel heavy on the head.
Cable and connections
The SR2 headphones make of use two 3.5 mm connectors on either side of the headphone housing which provide a solid click-in snap when the attached cable is supplied. The SR2 headphones come with a special copper-silver alloy able in a 4-wire braid to keep internal resistance to a minimal. The cable is very high quality and comes terminated in a 3.5mm jack. The 3.5mm to 6.25mm adapter is well-engineered and looks seamless once the 3.5 mm jack is screwed into its entry point.
The iBasso SR2 headphones have a unique tonality – a sound which is composed and detailed and yet possesses a certain softness and elasticity to its timbre. That is not to say that the overall sound is overly warm or relaxed because that it is not. Rather, the note weight is full with a certain element of richness without conveying harsh leading transients or crispness.
The SR2 imposes a mid-bass bias when compared its sub-bass. While the low-end has a pleasing timbre, bassheads may find this presentation light where the very low frequencies are concerned. The mid-bass is tuned to be slightly more elevated with a gentle upslope in the 50 Hz to 100 Hz region.
This allows frequencies here to possess more body while retaining the low distortion, agility and decay of the carbon fiber diaphragm units. Overall, the iBasso SR2 has a more musically inclined low-end with a rounded character and solid grounding. Next to the Deva (wired), the SR2 crafts a richer tone compared to the former’s more analytical spin on tracks.
Following suit from the elevated mid-bass, the midrange of the SR2 is equally smooth and rich without ever sounding congested. The timbre lies slightly on the neutral-warm coloration of the spectrum and there is an abundance of macro-dynamics littered with micro-dynamic cues. The presentation never gets lean or strident and this is a recurring theme in the SR2’s sonic signature.
This is likely owing to the gentle roll-off in the 3 kHz and 9 kHz territories – areas susceptible to peaks and stridencies. The midrange is placed slightly forward in the mix with decent levels of separation between forefront vocals and background instrumentals. In some ways, the SR2 recalls the same foundations of the Meze Empyrean – a slightly darker, rounded and yet tonally rich sound albeit less technically proficient than the latter.
The upper midrange and treble pick up some elevation in the 3.5 kHz to 6 kHz restoring some energy in this section. Drum snares and cymbal crashes are not overwhelming with good decay as demonstrated in Elton John’s ‘Rocket Man’. There is a slight unevenness in frequencies above the 7 kHz region – perhaps iBasso could make this region more linear to extract even more extension and air. Though, the lack of fatigue and forgiving nature of these headphones do make it perfect for extended listening sessions.
Imaging & Soundstage
Despite the low midrange weight and tonally rich sound, the iBasso SR2 headphones possess very good instrument separation. There is an adequate amount of headroom when listening to moderate listening volumes. Vocals do sound more forward in the mix and this does give the presentation a slightly more intimate sound compared to other planar offerings. While the SR2 have been labelled as ‘open-back’ compared to their ‘semi-open back’ SR1 brother, I have found there to be minimal sound leakage which is a bonus.
HiFiMAN Deva (wired) ($299)
Compared to the HiFiMAN Deva, the iBasso SR2 projects a richer tonality with the overall note size being fuller than the more analytically driven Deva headphones. The Deva has the faster transients and decay whereas the iBasso SR2 sounds more natural and is the more forgiving of the pair. Overall, the two headphones tackle high-fidelity from a different angle with the Deva going the conventional route and the iBasso SR2 infusing some musicality into the mix.
Sennheiser HD600 ($300)
The HD600 by Sennheiser still stands the test of time as an outstanding value for money headphone. Compared to the SR2, the HD600 delineates a more neutral sound profile. Like the SR2, they work well across a wide variety of genres. However, the HD600 really shines and scales well with powerful amplifiers whereas the SR2 sound great from a smartphone or laptop.
Character wise, the HD600 has a livelier sound as denoted by more energy in the upper end of the frequency spectrum. By comparison, the SR2 headphones trades this liveliness for a smoother and richer texture.
ZMF Verité Open ($2699)
Both the ZMF Verité Open and the iBasso SR2 incorporate dynamic drivers. However, where the ZMF Verité makes use of beryllium, the SR2 opts for bio-cellulose as part of its design. Both headphones share a pride for low distortion owing to their clever use of materials. However, the Verité sounds the faster of the two headphones with a punchier attack and resolve.
The SR2, on the other hand, possesses a slightly more rounded tonality with a more relaxed sound. Both headphones have excellent layering, however the Verité Open takes this one step further with excellent front-to-rear imaging.
Meze Empyrean ($2999)
Although the Empyrean is significantly more expensive than the iBasso SR2, both share some similar features of an easy-going tonality with little to no sibilance or harshness. This extends across their fluid, musical and forgiving nature. The Meze Empyrean does however pack in more resolution and air compared to the SR2. There is also an increased level of refinement and cohesion in the Empyreans next to the iBasso SR2s.
Since the SR2 has an impedance rating of 24 Ohms and sensitivity of 108 dB/mW, it can be driven easily without any concerns. However, it does scale well with certain players. For example, the Lotoo PAW 6000 adds some more layers of separation and detail whereas the Cayin N8 instils more headroom and low-end impact.
The SR2 headphones are a high-quality release from iBasso improving on the aesthetics and craftsmanship of the SR1s. It nice to see that iBasso have developed their own proprietary drivers within their own suspension via their in-house engineering team. This shows a willingness to become an authority in a field rather than re-tuning or adopting off-the-shelf materials.
The iBasso SR2 sound is certainly distinct with a neutral-to-rich presentation coated with great macro-dynamism, transient response and three-dimensional layering. While it is not the last word in detail retrieval nor does it have the most extensive treble, its sound would attract those in favor of a slightly darker and richer profile. To this extent, the iBasso SR2 headphones are a very well-built offering with an affable signature from the get-go.
iBasso SR2 Headphones
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