Introduction & About the Billie Jean
Billie Jean is one of the latest IEM offerings from Astell& Kern is famous for digital audio players. They launched it in association with JH (Jerry Harvey) Audio. It comes from the SIREN Series of JH models.
Design, Build Quality, Comfort and Fit
Billie Jean has 2BA 2Way per driver design and uses one the lows/vocals and the other one for the highs. It features JH’s free phase (phase waveguide) technology which corrects the phase shift inconsistencies by precisely cutting the tube lengths for each driver. It also incorporates the JH’s acoustic chamber bore which helps to widen the soundstage.
The packaging is very nice and beautiful and comes along a well build sturdy store pouch, 3 pairs of silicone tips (S/M/L), much thinner and lightweight copper plated silver cable made by Kevlar with a 3.5mm SE L plug. Billie Jean utilizes the standard 2-pin (0.78) plug on the drivers. Right channel connector has a red dot for easy identification and left is left blank.
Coming to the fit and comfort Billie Jean is one the most comfortable IEM I have used. The plastic body shell is much lightweight and small in size and has a longer nozzle ending. After matching with your size of silicone tips you forget wearing this IEM even after a few hours of listening. Smaller size, thinner cable, light-weight and comfortable and sealed fitting which makes this IEM very good commute and travel.
Usability and Functionality
Billie Jean’s impedance is measured for 18ohm but unfortunately AK or JH is not providing other technical information like sensitivity or frequency range which not a usual practice in the industry. It is easily drivable from a DAP or mobile phone but needs 25% to 30% more volume level than highly sensitivity IEM pair, which makes to be believe that the sensitivity somewhere near 105dB or so.
The Kevlar cable comes along is really nice and feather-light and there is no microphonics during movements or walking. So this makes it ideal candidate for brisk morning walks or hitting the treadmill.
The silicone tips come along is very good and provides nice sealing and fit and I think it matches most people ears for good. You can get the after-market tips but the need to consider the nozzle size and length. The carry pouch comes along really good for store and travel and the hard material construction provide good protection.
To be honest, usually, I don’t prefer the sound signature of BA drivers. So I will try to be more objective than a biased assessment.
Let me start the bass as there is a popular belief that BA drivers cannot achieve the level of low frequency which dynamic drivers can produce. Billie Jean gives a good and enjoyable mid-bass and upper-bass but doesn’t extend well to the deep sub-lows areas. The attack/decay is good and fast like a planar this makes like genres like EDM and Pop music much enjoyable but slightly lacks the rumble or texture of DD driver.
Coming to the mids Jean holds a V-shaped presentation signature with a dip around 1k at the frequency response which makes the mid-range go slightly backward but they are catching up in the upper mid-range which makes overall presentation very good. There is enough weight there but it has not into the face sounding which makes the overall vocals feel like the way natural.
The highs are well extended but they are very smoothly rendered but slightly lack the airiness. Looking at FR there some small dips between 2k and 7k and a peek at the 7.5k which drop down well at 10k and keeps that level till 17-18k. Contributing to the V tuning the highs are more in forwarding nature but they are not sibilant or fatiguing which makes it good for long listening sessions. The presentation is energetic which you can expect from the BA drivers with fast decay and cleaner sound which really enjoyable.
Sound stage and width is good and definitely not in your head but just that outside and near to the sides of your ears. It shines on instrument separation and the is also imaging is very nice. There is one of the good strengths of Billie. You can easily pick each instrument and nicely place them in and around you.
Overall these characteristics make Billie Jean really enjoyable IEM for modern music genres like EDM, Pop, and Rock, etc. That doesn’t mean this not suitable for old classic or vocal-centric music but Jean can shine more with its capabilities in modern genres.
Personally I don’t have any BA IEMS in my little stable do one to one comparison and should be unfair do with DD ones. Sonically Billie Jean cannot match up with the rumble and timbre of lows like the single DD iBasso IT01s however it shines within its capable areas.
Billie Jean is a solid light-weighted IEM, easy to fit, much comfortable and much suitable for outdoor use as well with its noise isolation fit and zero microphonic cable. Sound signature wise it really shines with its imaging, instrument separation, soundstage, and resolution. It has fast impact bass, not that deep though however very good and bodied upper-mids and sibilance free clean extended highs which drops little early which is good in one way. All this makes it an ideal candidate for modern music genres.