Acoustune's house sound is generally a well-done V shape signature. Their single DDs though on the pricier side, generally have quite good resolution that can rival some multi drivers.
At the Singapore CanJam I found they released a Mk2 of their flagship, called the HS2000MX MK2. The Mk1 has a beryllium driver but this version 2 is marketed as the world’s first IEMs with replaceable acoustic chambers!
With the stock chamber, the HS2000MX MK2 sounds mildly V-shaped, with brilliant technicalities and crisp transients. The other four modules are sold separately, and they change the FR when installed.
You just pull out a holding pin and slot the new chamber in.
There are five different acoustic chambers to play with:
- Stainless steel + birch wood module
- Brasa wood module
- Aluminum module
- Brass module
- Copper module (stock)
It ain't cheap though. The IEM itself is like $2K SGD and only comes with the stock copper module.
Many modern day ChiFI at sub$20 easily eat the Shure SE215 for breakfast, lunch, dinner and supper.
I thought it was a muddy a decade ago when I had it, and it is still amazingly sold today, and without a significant price drop. The only good thing I would say it has a good fit and is quite durable.
I have been testing out the R6 Pro II tour unit the past day, it has quite good technicalities, neutralish.
UI is quite fast, user friendly and quite solid build. You can change between a class A and AB amp on the fly. Sound wise I have no complaints TBH.
But some bugbears - battery is bad. Like 5 hours or so on class A on 4.4mm, it gets warm too. It isn't the most powerful DAP at 383mW max output on 4.4mm. It can drive the HD650 (300 ohms), and Final E5000 (low sensitivity) quite decently on high gain/4.4mm, but it couldn't push the Yinman 600 ohm 2.0 earbuds (87 dB/mW sensitivity, 600 ohm impedance) that well. I suspect it can't drive some fussy planar headphones too.