Love my Senn cans. But really, other than the HD6 line (how old is it?) and the HD800s (how old is it?), what innovation has been done in the past decade (audiophile specific). And no, the Chinese are not the problem with their cheap headphones. If you want to see a European company that seems to have zero problems in this space, just hop over the border and visit Focal. Sennheiser simply has a normal business problem: leadership is clueless.
Actually, the recently released HD560s is an example of
new, major audiophile innovation by Sennheiser. They cost the same ($200 USD) as the HD599, but are UNFATHOMABLY better than other HD5__ series cans (except the 58x but that's Massdrop and is really an HD6__ series can under another name, haha). They have AWESOME bass-extension for a mid-fi dynamic open headphone, a nearly
ideally-flat/neutral tuning except for a treble-spike centered at 5Khz (the spike isn't as bad as some make it out to be, it's WAY less painful than Beyer or AKG treble, or god forbid Grado treble); their frequency-response is basically like an HD6__ series headphone with the addition of good bass-extension and a minor-ish treble-spike.
They have MUCH better soundstage than the HD6__ series or HD58x, and very precise imaging. Their detail-resolution, speed, and decay (which can be clearly heard, and seen in CSD plots and impulse response), while not AS good as the 6__ series, is a LOT better than other 5__ headphones; I'd say detail and speed are midway between the 5__ series and the 6__ series. Their distortion is as low as HD6__ series. They have EXCELLENT dynamics. They're almost unbelievable for only $200, their only truly major competitor for sound-quality in that price-bracket (keep in mind I don't like Beyers or AKG's) being the Fidelio X2HR's, but those are very DIFFERENT (the X2HR are less "analytical," more "fun," more stage-width but less depth/height and less precise imaging than the HD560s, and an equal treble-spike in the same 5Khz area) and are plagued by common quality-control issues like channel-matching (I had to go through three pairs of the X2HR's before I got one with proper channel-balance, and some people go through as many as six pairs).
So yes,
in at least ONE case, Sennheiser has made a MAJOR innovation lately with a wired audiophile headphone, a headphone for $200 where there is only one true competitor in the price-bracket which is a side-grade (and has very unreliable QC), and where the only true upgrades cost $350 or more (people say the cheapest true upgrade from the HD560s or a good pair of the X2HR's is the Sundara, and having listened to multiple headphones in this price-range, that seems true).
Why is the case of the HD560s so important that I'm posting a giant wall of text about it? Because
it proves that Sennheiser IS still CAPABLE of innovation and massive improvements over past models. People thought it would just be another side-grade of the HD5__ headphones, but instead it proved to be a HUGE upgrade. Moreover, IT HAS SOLD REALLY WELL: Every production-run of it that they make ends up selling out, they've been unable to keep up with demand for it!
The HD560s is why I have faith that IF the investor/partner that Sennheiser finds places value on their audiophile line, Sennheiser will be capable of good innovation in that area, once again matching up to or surpassing their competitors as they once did. So
we need to cross our fingers that the new partner WILL place priority on the audiophile line; if they do, then Sennheiser can do incredible things for us! It's possible that if the new investor is smart, we could end up getting TRUE successors to the HD6__ with proper soundstage, and a proper upgrade to the HD800 series that maintains its great soundstage while fixing the wonky frequency-response.