Review: Astell&Kern Billie Jean – The One

Astell&Kern Billie Jean


Aftermarket cables:

I really like to play with aftermarket cables in reviews, because it’s fun to see how the monitors react to different materials and cables. Of course you have to stay within a certain price point, otherwise it’s getting ridiculous. In my opinion a cable should never be more expensive than the monitor, but I know many people out there play a different game.

Effect Audio – Ares II

The Ares II is a wonderful Copper cable that has a very nice timbral presentation. It gives Billie Jean a warmer and more vibrant lower midrange with added bass-body. Overall the sound seems cleaner to me, with higher dynamics in low-ends and a richer top-segment. The sound stage also expanded more into width and depth with greater layering and instrumental separation. Vocals, especially male, received more weight and body. Treble still is clean as a whistle while being tamed by a slight margin.

PlusSound – X (GPC)

The X series is the pinnacle of portability in an IEM cable for me. It’s lightweight and ergonomics are unmatched. Maybe Linum offers a similar performance, but I don’t have any of theirs here, so PlusSound it is.

The Gold Plated Copper X series offers wonderful transparency throughout the frequency, with very nice resolution and instrumental separation. It beefens up the bass on Billie Jean, extends it’s bass response to deeper levels and gives treble a nice warmth and richness which suits the AK IEM very well. Sound stage does also go a touch wider and deeper, yet not as much as with the Ares II.

Astell&Kern Billie Jean

Astell&Kern Billie Jean


The Billie Jean is not a hard to drive monitor, also it does not need excessive power to be at its optimum performance. What is quite obvious though is that Billie Jean scales well with better sources. All impressions were done with the stock cable.

Astell&Kern – SP1000

The A&ultima of course pairs very well with the AK monitor, there’s not the slightest hissing to be revealed. The Billie Jean reaches fairly deep into sub-bass with great dynamics and good texture. The overall signature is more on the brighter side, but with excellent richness in it. The sound stage stretches wide and deep, with wonderful instrumental separation. The background is nicely black. Mids are fairly neutral but with good body and weight. The resolution is outstanding and the same applies to stereo imaging and layering. Treble might be on the brighter and sometimes harsher side,

Chord Electronics – Mojo

The Billie Jean picks up very slight hissing from the Mojo, but it disappears once the music is playing through them. To me this might be the best pairing of all. Dynamic, well layered and excellent separation. Bass is punchy and deep, with great body and weight. Billie Jean reaches deep with good rumble. The sound is clean and precise with good speed and decent warmth to fill up the signature. Mids are well bodied with a natural appearance and good amounts of emotions. Treble is fast and precise with a bright tone. The sound stage again is nicely wide and deep.

Astell&Kern Billie Jean

Astell&Kern Billie Jean

Chord Electronics – Hugo2

The Hugo2 is also not free of hissing with the Billie Jean, while it can be heard easier than with the Mojo, it also disappears once the music starts playing. The Hugo2 is a resolution monster and that is very clear with the AK IEM. There are loads of information displayed right in front of you and the level of micro detailing is just incredible. Bass is punchy and dynamic, has excellent texture and goes deep into the sub-bass regions. Midrange is more on the neutral side with heeps of emotions, but is presented in a more airy manner. Treble might be a point where some could draw the line. While the Hugo2 usually covers it’s top end with a silk layer, I fear it is not always the case with Billie Jean. The sound sure is top class level, but for some it might just be too bright and too hot at times. The sound stage is incredibly wide, deep and high. Definitely the best of all tried units, but what good is it, if the overall sound is just not pleasing. Layering, separation and imaging are of course also top notch.

Luxury&Precision – L3 Pro

A DAP I like to use when I’m on business trips. It’s not as extravagant as the A&ultima, but delivers a very nice sound with good levels of musicality and decent warmth in it. The UI is pure crap though. You will get a punchy and fast sounding, well layered and highly resolved pairing with the Billie Jean. The level of details is very good and the instrumental separation is as always with Billie Jean outstanding. Mids are warmer and have thicker notes and heavier weight, but they don’t come across as too thick and slow.

The final page is all about Comparisons and Conclusion.


A daytime code monkey with a passion for audio and his kids, Linus tends to look at gear with a technical approach, trying to understand why certain things sound the way they do. When there is no music around, Linus goes the extra mile and annoys the hell out of his colleagues with low level beatboxing.


    • Reply August 14, 2018

      Andrew Candeloro

      How would these be next the oriolus forsteni in terms of sound signature? Im leaning towards the forsteni but am scared of all the comments saying they are too hot sounding.

      • Reply August 15, 2018


        Hi Andrew,

        thanks for your comment.

        Sadly I have never heard the Forsteni myself. If you have the chance to audition Billie Jean or the Oriolus, it would be best to do that. I know people can be very sensitive to treble, and I said it in the review that Billie Jean might be too much for some. So you really should give it a demo if you’re concerned about it. I’m fine with it, but that doesn’t mean you are…


    • Reply August 17, 2018


      I originally planed to buy a pair of Westone UM 30 pro but my local shop stop selling them. I tries these out to see if they would fit my taste. I like what I hear except for the mid. I find the mid range, especially the vocal, to sound unnaturally thin in comparation to other iems i tried that day.

      Can you suggest other iem in the same price range with similar sound signature but fuller mid range? Thank you!

      • Reply August 21, 2018


        Hi Srs,

        I truly wish I could help you, but unfortunately I can’t. I know Berkhan is a fan of the Oriolus Forsteni, which has a similar price and might suit your taste. Though I’m not sure if it still is available.

        • Reply August 24, 2018

          Andrew Candeloro

          I’ve contacted oriolus and they said by end of August they should be available.

    • Reply November 14, 2018

      Sagar Shah

      Can you compare A&K billie jean with Etymotic ER4XR?

      • Reply November 14, 2018


        Hi Sagar,

        thanks for your comment.
        Sadly I can’t, as I haven’t heard this one, sorry.

    • Reply February 12, 2019

      Sandro Mosca

      How does the Billie Jean compare to the Weatone UM 50 Pro?

      • Reply February 14, 2019


        Hi Sandro,
        thanks for stopping by and leaving a comment.
        Unfortunately I can’t help you there, as I haven’t heard the UM 50 Pro, sorry.

    • Reply December 30, 2019


      Can you reply me with a comprison with billiejean and rha t20i

      • Reply December 30, 2019


        Hi Syam,
        I wish I could, but I haven’t heard the T20i ever. Also, I only do comparisons to models I have heard extensively and have at home. Anything else wouldn’t be reliable in my opinion. Hope you understand.
        Have a great 2020!

    • Reply January 11, 2020


      Hi Linus, just ordered a Billie Jean because of your review 😉

      Just curious, have you ever tried the AK Michelle Limited? I’m curious how it compares to the newer and cheaper Billie Jean.


    • Reply September 15, 2020


      can you compare the Billie jeans with the thieaudio L3 or the bgvp dm6 or fiio fh3

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