I managed to get the treble to extend all the way up.
Took a ton of EQ and it also took me to use my custom ESS chip stup for it, but what I can make out of this is that many DAPs and implementations are actually a bit rolled off and 99C responds to that (?)
(Talking about physical roll off, I did EQ them to get this well extended in both ways signature)
EDIT::: This is actually why I haven't reviewed them yet. I wanted to make sure whether there is any roll-off in the treble or bass areas, but after enough fiddling, I can safely say that they can be managed to have no roll off and extend to 20kHz with no problems.
My glasses broke less than three days before the Nintendo Switch came out, and I had earmarked a huge amount of money towards it (ignoring certain stuff I got in preparation too, like the Ultimate Ears Boom 2 wireless speaker and TaoTronics TT-BA07 Bluetooth Transmitter/Receiver), so having to fork out under £250 for a new pair was a blow, but worth it (vast majority of that cost was for the lenses, the rest was frames and eye test).
A day before the Nintendo Switch release, I got a call that my new lenses were in and ready. Whilst I waited for the spectacles with the expensive lenses to be completed, took a nice chilled break, having fun on Pokémon and enjoying both SBTRKT and Lusine via Tidal.
@MezeTeam I just realized that you guys offer new earpads on your website. Are these the same that are on the classics already or are they slightly bigger? (I already have a later version of the Meze 99 Classics with the bigger pads than the early versions).
So here we are just over a week in. I reckon I'm just past the 40 hour burn in point and I can speak more clearly about my impressions of the 99C's. The bass seems to be getting better as time goes on. Listening to "Forgotten places" by Alif Tree there is a pronounced double bass line which sounds wonderfully fluid and tactile without being boomy. This track would highlight bass inadequacies quite clearly and I'm happy that the drivers in the 99C's are subtly changing for the better. The bass has P.R.A.T. whilst remaining warm. The treble seems to have smoothed out and become more detailed as well. These headphones are so easy to listen to and yet they are not "easy listening" in their presentation owing to the vivacity and musical pleasure they convey. My first week has been immensely satisfying and I'm glad I didn't splurge on the B&W P7 wireless I'd auditioned in a shop the week before. These headphones are much better than those, although the bluetooth convenience would have been nice. I'm glad I resisted and trusted myself to go for 99C's. I would also like to thank the many reviewers on Head-fi and other forums whose opinions and reviews proved so invaluable. Sometimes it is difficult to audition headphones and one has to go by the sound signatures described by other enthusiasts. The relative comparisons by certain members about headphones whose sonic signature I know well helps one to get quite an accurate impression of the sound of a particular model and one can make quite informed choices based on those. I certainly got lucky in my choice with the 99C's.