Sound Impressions
Before working on the sound impressions, we are giving the R9 100+ hours of run-in, it is recommended to do so as the dynamics will be enhanced slightly.
I used FiiO’s latest FT5 planar headphones, a Shanling MG800, Moondrop Venus and PARA, the classic Sennheiser HD 600, and sensitive IEMs like the HiBy Zeta to test the phone outs and hooked it up to the RME ADI-2 PRO to test its USB output quality.
Summary
The R9 packs a lot of horsepower to feed the 8-channel implementation and it is not hard to imagine the output would sound very powerful and with stronger separation and detail retrieval power.
Indeed, all outputs have a strong sense of energy yet there is excellent control maintained, densely containing the power within notes, and not bleeding over or getting peaky.
Similar to other THX AAA-788+ devices, the overall tuning is on the neutral side and is quite dependent on the mastering or file quality as it may feel slightly dry with lossy tracks.
There is a small hint of warmth from the powerful bass, so I would classify it as a slight V-shaped tuning. The two ends are very well extended, yet the cleanly presented vocals don’t feel sharp but rather rounded.
Bass
The strong swing from the high output gives all pairings a great sense of energy and power, and the tight bass response has good synergy with R&B, acoustic, techno, and house tracks, basically anything with strong beats and big bass in the mix or with a lot of strings.
This works for headphones with higher impedance which will be particularly benefitted from the high level of power offered by the R9.
You can easily feel the sub-low’s presence, but it is not glass-shaking and does not bleed over the bass. The fundamental bass frequencies of instruments are also prominent, and you can feel the weight of the lower notes of the piano or the bass guitars.
When testing with fast guitar slicks, the R9 showcases good attack speed with a clean yet sufficiently elaborated decay that allows you to hear the reverberations fading in the air, and it sounds very expansive as good depth is achieved.
Mids
The midrange is tuned quite swiftly and evenly, so you won’t feel it standing out a lot or being altered. It is also notable that the density, or weight of notes in the midrange is clearly enhanced on the R9.
It feels more realistically textured in tone when testing with well-mastered, high-resolution tracks. The tuning is also quite friendly for streamed media to sound clean in the midrange.
Another noteworthy area is separation power. With the 8-channel implementation, or dual THX-AAA 788+ amping, the separation has been much enhanced, and you can hear instruments and voices across the midrange, distinctively positioned and sounding more authentic.
The high output power can put some stress on the lower bass and the upper mids, but the leading edges are sufficiently rounded so it doesn’t feel hot or uncontrolled.
This enhances the dynamic range, keeping the mid-range swift in articulation, and detailed in presentation but not stealing the show. Overall, in an unruffled way, the mids are presented, very cleanly outlined but may get slightly dry for expressive voices.
Treble
The treble on the R9 is well-extended and textured. You can hear the transients and the air with the upper harmonics nicely captured, which adds good vividness to singers who are expressive in the higher register, and adds good openness to strings and woodwinds so they don’t sound contained in the concert hall.
There is ample energy in the treble, but it is not overflowing, instead, it is well-controlled so it won’t sound too metallic or push the vocal details too forward and ruin the musicality. It feels quite refined and rounded and works with different voices to sound satisfactorily transparent.
Staging & Dynamics
The staging performance on the R9 is excellent thanks to its high power and smooth tuning, which enhances the perceived dynamics, clarity, and spaciousness even at higher volumes.
It can capture the nuances and you can feel how the voices resonate and project throughout the venue in a good mastering, with a good sense of depth and height.
While the increased voltage swing heightened the output levels and distortion control, it also helps with handling dynamic peaks and has good control over strong transient changes, particularly for Classical music to sound expressive when depicting a sudden change of mood.
Although the vocal image isn’t pushed very upfront, it is clear sounding. Vocals do not feel curtained when there are multiple backing instruments and can cut through the backing with good clarity at all times.
Synergy
Efficiency
Testing with the HiBy Zeta with a 9Ω, 112dB/mW rating, the R9 is very quiet in the background, and even at the highest gain level, you can only hear very faint hiss. That means you can focus on the music entirely and if you are detecting some noises, it is probably from the mix itself.
Power
With a balanced 7.3w maximum output power capability the R9 is capable of driving high-impedance headphones like the Moondrop Venus without a sweat, and it can deliver sufficient current to some of the less sensitive gears.
The higher power and gain are more beneficial for headphones with higher impedance. Yet when connecting with some sensitive IEMs such as the HiBy Zeta mentioned above, the R9 still manages to sound controlled and dynamic with good distortion control, without flattening out the output or sounding dull.
The tuning together with the high power works well with open-back designs. When testing with the HD 600 and the Shanling MG600 semi-opened back IEM, the bass sounds very impactful and has sufficient fullness.
Pairings
Using the highly sensitive HiBy Zeta with 9Ω impedance to test, the R9 is capable of delivering punchy bass and overall dynamic sound without overdriving the earphones.
With various IEMs, the R9 provides a clean response with decent bass texture, good air, and dynamics. It pairs well with gears that have stronger coloration, and I often prefer giving a slight mid-low bump for Pop music.
However, mastering on streaming platforms can sometimes enhance the overall sound. Classical music offers a sense of linearity and control, but with vocal works, particularly poor recordings, the tone may come across as slightly dry.
The R9 effortlessly drives sensitive planars like the FiiO FT5, delivering solid bass impact. It generally operates well on low to mid gain, but increasing to higher gain levels may result in sharper vocals and more prominent upper treble details.
The bass response is fast and dense, with a distinct and separate mid-range from the lows. Even when using a 3.5mm terminated cable, the R9 performs quite well and adds a stronger sense of warmth to the midrange.
When testing the Moondrop Venus which has low sensitivity, the R9 effortlessly provides an expansive soundstage with excellent transparency.
The bass impacts with ample power and agility, exhibiting both fullness and well-defined texture and layering. The pairing demonstrates strong dynamics and air, allowing for a clear distinction between instruments and their individual presence.
The R9 can effortlessly drive many older headphones through its 6.3mm output, resulting in a dynamic and airy sound signature.
The 5 gain steps provided are useful for matching different gears and adjusting tonality according to personal preference. The 6.3mm output tends to sound more musical, while the balanced output offers a cleaner and more powerful sound.
