Btw, I found that they share the same drivers. Below are some descriptions by the local distributor of TFZ at my country:
"If you’ve poisoned by the gigantic 12mm Graphene driver of TFZ Exclusive King, don’t miss out the newly released Series 4 and My Love II which are also using the same drivers.
In simple, they are the “warm sound version” of Exclusive King. They’re also using the HiFi level nano-diaphragm that made of Graphene, titanium plated dome, dual crossover & dual magnetic circuit, N52 magnet unit...which can produce high resolution and crystal clear sound quality.
Compare to Exclusive King which is more like a “studio monitoring version”, Series 4 and My Love II sounds more musical, warmer and analog. They are more suitable for vocal and acoustic music, and able to represent the emotion of vocalist lively.
Series 4 is a same level product with King with different sound signature. My Love II is the simplified version of Series 4.
Both of them are using high quality 4-wires silver plated cable. Detachable design with 0.78mm connectors (same with CIEM). You still can improve and tune the sound by upgrading cable in the future."
Link to forum:
https://forum.lowyat.net/topic/3953593/+120
Also, can't wait for a review from B9Scrambler about the Series 4!