While hybrids and tribrids been dominating IEM market for a while now, Mest made its mark as one of the first quadbrids (maybe not the first since I can’t keep a track of every single worldwide release, but definitely one of the first), featuring a total of 8 drivers grouped in 4 types: DD, BA, EST, and Bone Conduction. Just like the OG, MKII features 4way quadbrid design with a 5-way crossover, including DD bass driver, 2BA mid drivers, 2BA treble drivers, 2EST ultra high drivers, and one full range dBC dual sides Bone Conduction driver.
In contrast to a single side BC driver in OG, MKII now uses double sided piezoelectric bone conduction driver which is placed in between two supporting plates. At the center of that BC driver is the vibration board covered by ceramic coating on both the front and the back. Also, this dBC bone conduction driver now has a larger contacting area with the shell and has a wider effective frequency response range from 500Hz to 20kHz, in comparison to OG with BC that covered 1kHz to 16kHz.
I know many will be asking, can you “feel” the effect of dBC driver? It is hard to tell because based on the fit with my ears, I didn’t feel anything different, and to me this is just another sound contributing driver. BUT, when you are comparing tuning of OG vs MKII, there is a distinct presence of more body in lower mids and this could be a direct contribution of dBC driver extension down to 500Hz from the original 1kHz. Would have been cool if they added a switch to enable/disable dBC, to be able to hear the effect of this driver. But either way, it is unique, no pun intended, again.
Just like in OG design, the shell is lightweight, durable, and made from one piece carbon fiber. This is important because it improves the effectiveness of dBC driver due to its contact with a shell. The carbon fiber finish is infused with gold foils, a very nice look that goes really well with PWA all black cable with its hardware that has gold screws accents. And you will notice upgraded faceplate metal vent which controls the air flow going into the DD driver. OG vent wasn’t metal plated.
Another improvement is 2pin socket which is flush with the shell, better for aftermarket cables in comparison to 2pin convex socket which sticks out in OG design where they used cable connectors that wrap around it. Those convex sockets could be used with regular 2pin cables as well, but the cable connector will be sticking out too far out which could affect the fit of the cable over your ears.
But the biggest improvement was a smaller and more compact shell design with improved fit. While it was nice to see the inner side of the shell in MKII to be more custom-sculptured, the change in the angle of the nozzle from OG to MKII was a noticeable improvement for me. With OG I felt a little pressure while MKII was just perfect. Of course, it will depend on your earcanal anatomy, but in my case, it made a noticeable difference.
And last, but not least, the top of the metal nozzle, which is covered by a protective mesh, in MKII has a little bigger diameter. The difference is not huge, but it is bigger when you look closer. I think if you were OK with OG Mest, MKII will not be a problem. But if your earcanal is small, Mest offers both Universal and Custom versions of their IEMs. And for me personally, while I typically use Large size eartips, I end up using Medium size eartips with MKII due to a bigger diameter of the nozzle.