Very interesting videos, I watched both all the way the through from the beginning. My own general perspective on Sennheiser before I start talking about the vid: I'd say in overall terms my best headphone is a Sennheiser headphone, the HD560s, so I'm interested in Sennheiser products and I think they really do make some solid headphones, both in terms of sound target, but also in reliability - low unit to unit variation, good channel matching, and can be used for years without failing (got the HD600 too).
I'm gonna list a few points I thought were interesting from the two videos:
- 90% of headphone tuning is achieved by the design of the transducer, the remaining 10% that contributes to the final sound is shape of the earcups/pads/dampening. They design & make their own transducers, can take years to design a product, did he mention up to 10yrs, but often around 2yrs. I was really surprised to hear that the transducer is what shapes 90% of the frequency response/tuning, I thought it was gonna be considerably less than that.
- Harman Curve: they basically said HD600+bass shelf, confirming what we already knew back in the 90's. (They did say the Harman Curve research was very important and notable though.) More than just the measured frequency response they mentioned. But they do use measurements rig though in the development process. They didn't mention if they measure in-ear on real humans for frequency response though, to see if there's large variation between people with certain headphone designs for instance - HpTF variability. Perhaps they're more seperating themselves from measurements done on rigs, in terms of being strict about a target frequency response - because they say of course they tune them by ear as well as measurement. My thoughts: I'm less confident that large straying from Harman is beneficial, although I can imagine targetted and/or small'ish tweaks around it to cater for different tastes could be useful, but a fair few of their headphones seem to track Harman well, better than many other manufacturers from that point of view.
- HD800s. Baffle manufacturing variability (metal mesh) in terms of 150-300 "Sennheiser ohms", therefore they match transducer to the correct category of baffle. Different groups of baffles & different groups of transducers, they know which groups of both they need to match to get the "same" frequency response. How they control the frequency response of the HD800s so that there is minimal unit to unit variation. Perfectly matched channels, imaging, one of the reasons why they think it's done so well. And my thoughts: a good argument for getting a miniDSP to EQ both your channels to perfectly matching through whole frequency response range - for other headphones (I've done this, I think it's worth doing). I thought the length they go to control unit to unit variation & channel matching in the HD800s was pretty cool.
- HD560s. Started off in Jermo's basement (guy on the right), 6'ish months to develop, very quick, even though they did develop & manufacture a specific driver for it.
I thought it was good that these two significant players in the Sennheiser R&D team were young (good ears for one thing), but also their enthusiasm and energy, but it was also good that they were more on the nerdy side rather than somekind of Youtube influencer or something (lol), which is good because you want them to have a scientific approach backed up behind their enthusiasm. I'm not using "nerdy" as a negative term, because they came across well on the vids and explained stuff with enthusiasm and energy and their own personality which helped make it interesting.
