Ever since I had my ears on the AK120ii some years ago, I have jumped on the AK sound. I really like how their engineers have realized this level of sonics. I heard that their main-sound-engineer spends three days or so without eating before he sets on a device’s signature. While alarming, this also shows quite some dedication to the job.
As mentioned before, Astell&Kern has two outputs. I have mostly been using the 2.5 mm balanced one, as most of my cables are terminated to that plug. I will go over the differences between balanced and unbalanced later. One thing up front though. I know people say balanced makes no difference. While I agree that there is no general rule for that, I say, it is all about the implementation. The circuit matters. I know balanced outputs that outperform the single ended one, and I also know single ended one’s that sound better than their symmetrical counterpart. It’s all about the components used and how well they act with each other.
Astell&Kern DAPs are known for their silent background, and the SR15 is no exception here. With my most sensitive CIEMs I can hear a slight hissing during silent parts though. Especially the Empire Ears Zeus XIV picks up hissing easily. It does that also with the TOTL A&ultima SP1000.
The SR15 has a softer, full bodied and extended bass response, that shines with quality. It is dynamic and engaging, with good speed and a natural presentation, where especially acoustic bass sounds nice. The resolution and texture are both good. There is noticeable warmth in the sound of the SR15, even if it’s just moderate.
Lower mids are a tad more forward and enjoy a good proportioned body. There is again warmth in them. Midrange overall is well resolved and has excellent texture. Instruments come across as natural, well defined and accurate. There is sufficient air in the midrange for good separation. Imaging is also top on the A&norma. What I like especially in the midrange is the wonderful richness each instrument sports.
From a technical point of view the norma is a very competent performer. The sound stage is wide and deep, there is wonderful levels of layering across all frequencies and the placement of the instruments is carefully done and imaging can be achieved easily. Of course, most of it depends on the recording of the tracks, as the general rule applies: shit in, shit out.
Highs are well extended with good energy, sparkle and air. They appear a notch on the relaxed side of things, but aren’t overly laid back. Treble is rich and crisp.
When switching from balanced to single ended, I noticed that the sound becomes fuller and a bit bassier. You will trade in some sound stage size and also instrumental separation for that. The balanced output to me has higher levels of transparency and resolution. Bass is tighter on the 2.5 Millimetre, and seems better controlled to me. Midrange sounds more open and treble a touch more forward.
The SR’s sound to me is easy to like with good levels of musicality.
The SR15 is a portable product, and like most of this trade, it is intended to be used with efficient gear. The four Volts output level of the balanced out might indicate it has enough juice for demanding headphones, but since this is measured in no-load condition it pretty much says nothing. Most of my ear-time went into custom and universal in ear monitors though.
Jomo Audio – Quatre
The Jomo is a very good hybrid with tuneable bass response. For this pair-up I have used it with the standard black filter.
The combination sounds highly enjoyable and almost addictive. You will get a well formed and resolved bass, with good extension and control. A slightly warm sounding pairing with loads of emotions and very nice sounding vocals and instruments. Treble is filled with energy and of brighter sound, but not harsh or aggressive.
64 Audio – A12t
The A12t is a smooth and balanced sounding CIEM that knows how to throw a decent punch. The low end drive is spectacular and the same goes for the quality of its bass. The sound stage is very wide and deep, with all musicians placed accurately. The sound is open and airy, with excellent timbre and wonderful treble.
JH Audio – Layla
Monitors like the JH Audio Layla sound fantastic, with wonderful body and a highly organic appearance. You get good speed, resolution and a wide sound stage. Vocals sound impressive, with awesome emotions and a sound that’s portrayed in front of you. Sometimes I overlook Layla due to the fact, that there are so many different models in my inventory, but each time I come back to her, I enjoy listening to my tracks a lot. Especially acoustic genres impress me with this combination.
Earsonics – Grace
The Earsonics Grace I consider one of the best universals this year. It has a high PRaT factor and matches very well with the SR15. The combination is organic and engaging. The bass sometimes misses out on punch and drive, but the rest of it is of high quality. Midrange is well resolved and delivers a great natural sound with heaps of emotions.
Sennheiser – HD800S
For the sake of the experiment I also tried to run the HD800S balanced, which indeed got to loud levels (at volume 100 and above), but didn’t deliver the sonic excellence I know the Senn for. Sure, volume wise it’s enough, but the HD800S is nowhere of driven well. Bass is lacking extension and the entire music just sound present, but not alive in my opinion. I wouldn’t recommend using harder to drive cans with the SR15. It’s also not the prime purpose of the norma.
I found the smooth and slightly warmer sounding SR15 to be best matched with neutralish sounding In Ears that have a bit more bass on their own, such as the Jomo Audio Quatre, JH Audio Layla or 64 Audio A12t, but also the recently released Earsonics Grace sounds fabulous with it.
My favourite out of the above would definitely be the Layla. The level of enjoyment is just outstanding with excellent PRaT factor.
The last page is about Comparisons and Conclusion.