Beyond the Curve EP04 - Transducers | Sennheiser

[@spektrograf]

Thank you so very much for doing this Q&A. I really appreciate the clear and articulate description from both Meike and Jermo. I know personally how hard it is to describe technical ideas in a second language. Both did a fantastic job as the ideas were crystal clear. Thanks again! edit: I, also, have my original HD580's from 1996. They still see weekly use and sound just as good as ever-better now with availability of better headphone amps and DAC's!

[@zoltantoth1566]

Thank you for the continuation of your willingness to make these educational videos.

[@divinecurrent9053]

I would like to ask if Sennheiser has explored using planar magnetic transducers or even solid metal domes such as beryllium like other companies are using. Or even just metal coated diaphragms. I know there’s both benefits and compromises for these types of drivers as opposed to traditional diaphragm material Sennheiser uses.

[@sennheiser]

Thanks for your interest! We've experimented with all transducer types and continue to look at every emerging technology. Regarding diaphragm materials: Our "traditional" material is a carefully assembled patented laminate of a stiff plastic foil and a material with highly self-damping properties, so we get the benefit of a relatively stable diaphragm thanks to the stiff plastic. At the same time, the damping element effectively eliminates harsh resonances. When experimenting with very stiff cones, we found that the resonance frequency increases significantly, and the resonance itself becomes harsher with the increased stiffness, which may be audible through intermodulation distortion. Using stiffer materials took us away from what we consider natural sound reproduction.

[@Flavius7]

Always a pleasure to listen to the people behind your favourite products!👍

[@Farpun]

Absolutely love this series. Would love a HD6Series closed back.

[@dgrillodelambarri]

Love these exchanges! Learning so much with you guys ❤

[@FabioKasper]

23:09 the guests dodged the question on the diaphragm material. 😅

[@GrumpiestKitten]

Duofol. Laminated PET.

[@evshrug]

Well, the community question was how long can the headphone last, Eric added the question to ask what is the diaphragm made of (assuming that it would be the moving parts that fail first). The wires are definitely part of the whole transducer system, and since they (used to) fail first that is where Jermo directed his time. In a practical sense, considering the whole headphone, the diaphragm membrane is stiff but not “hard” where it will be brittle or break for a long time, the small connecting wires between the voice coils and headphone cable attachment point are placed such that very little “work” (bending) is applied to them, and most likely to deteriorate are foams that come into contact with the oils on our skin, and cables that may get run over by a chair or kinked from snagging on something.

[@akaria6359]

With Sennheiser Consumer and Sennheiser Pro being two different companies how does it work now with R&D and product development? For example, the Sennheiser HD 400 Pro is a rebadged Sennheiser HD 560 S with different accessories but the Sennheiser HD 490 Pro looks to be a unique product. Does engineer time get shared now between companies? What is that experience like as an engineer developing a product? Has Sennheiser considered doing limited edition drops of their products? That does seem to be the marketing fad now to make limited edition versions that are collaborations.

[@SheepDude-qp7ux]

Listening on my HD800! Intro music sounded insanely wide!

[@JosefKopal]

I am not sure if it is appropriate to ask here, but I am looking for specific cable which is similar to one used in the SENNHEISER MZC30 IS SERIES 1.1 MM KEVLAR CABLE SPOOL. It is meant to be used in a medical device prototype and possibly for production later on. Is there a chance to share details about your supplier or get the cable from Sennheiser ? Or at least to share some recommendations or proper contact in the company . Thanks a lot for your answer PS: I am owning a loving your headphones since 2009 :)

[@FabioKasper]

Great show folks. Merry Christmas! 🎄 🎁 🎅

[@zoltantoth1566]

"point-source" sound - this is one of the questions that people debate in the forums, some say that it is impossible to hear the form of the wave-front; i thought i heard it but was not sure; now i know, thank you; i went from very planar-like wave-front [Superlux 681] to point-like [Sennheiser 5**] and at the beginning of my transition it was difficult for me to accept the point-like nature but with time i think i got used to it

[@evshrug]

Jermo’s example of a point-source sound was the 7mm driver used in the new Sennheiser in-ear series headphones… imagine a multi-driver over ear headphone, and a transducer that small was positioned forward of the ear canal. As sound expands out from the transducer in the shape of an enlarging bubble, the radius of that bubble is very arched by the time it begins interacting with the outer ear and bouncing inside the ear canal, affecting the timing of when each part of that bubble bounces and is redirected to your eardrum. Meanwhile, a more planar sound wave is like a bubble so large that there is almost no arch curve as it interacts with your outer ear all at the same time, so the indirect parts of the bubble’s periphery take less time to be reflected to the eardrum. Essentially, the more planar wave sounds like a more typical sound to us, but a point-source has a unique sound that can only come from something very small and very close to your head, breaking the illusion that it could be a band or speakers performing out in front of you. I theorize that placing the 7mm transducer almost inside the ear canal and eliminating the outer ear interactions entirely makes it seem closer to the planar wave front with the very “fast” outer ear interactions. But, I am no acoustics expert, just an amateur internet theorist. Jermo and Meike are far more experienced than me!

[@eduardoestebanab8049]

Is possible to make a Open back ish In ear ?

[@zoltantoth1566]

Did you just say at 19:24 that you can hear in the mids distortions at 70dB that the machine measurement can not show? Most people say that the human brain is much less capable to hear distortions than the machine.

[@photominion]

that's what he said, after clarifying that it was his personal opinion. Because the distortions would not show up on measurements at such low levels of sound pressure output. His scientific explanation would support that, since the coil doesn't travel too far if the sound pressure level isn't very high, so the chance for it to leave the range of the magnet is minimal. My guess is that it has a lot more to do with the Impulse Response of the transducer. If the magnet is weak or the diaphragm "lazy", then it will take a long time for it to fully move into position, before it then slowly moves back. That results in a lack of "punch" and "slam". On the frequency response curve, that would not show up, because the system can still reproduce that frequency, just not "fast". At least, that's my understanding. If you have closed-backs of the same system (e.g. DT770 vs DT990) you will notice that they are usually "faster", simply because the closed back creates pressure that pushes the diaphragm back into position when it textends outwards.

[@zoltantoth1566]

@@photominion The human ear senses not the position of the diaphragm, but its amplitude. What is slow to reach is not a spacial position of the diaphragm but an amplitude value of its wave movement. Closing the back of the headphone does not help in that. I had DT 770, 880, TYGR - they sounded to me with the same [quit high] dynamism.

[@zoltantoth1566]

You started to talk about "dynamism", but at the end have not said much about it, or anything substantial at all even. What is "dynamism"? Focal says that it is something independent of the frequency response. I also feel so, because i equalize my headphones extensively and dynamism to me does not change with the frequency response, with any headphone. You said that it may depend on the magnetic field coverage of the excursion of the coil. But that is not convincing to me. Driving out of the magnetic field does not happen at low volume, right? But slow-sounding headphones [HD 600, Game One] do sound slow to me at low volume too. But the technically very close HD 598 sounds dynamic to me. Thank you in advance if you can shed light into my amateur mind in a future episode.

[@sennheiser]

Thank you for being so interested. As you rightly start off with, first one has to clearly define and align on different expressions to examine a topic with clarity. My answer regarding the compliance of the surround and a deep magnetic yoke with a very even magnetic field was related to the impression of "bass impact" or "slam", which to me is very different than "speed"/"brilliance". "bass impact" to me has a physical dimension, and while you can sense the capability of bass impact at lower volumes, it becomes very obvious if you listen somewhat loudly. For the HD 600 and HD 599 I personally don't hear a major difference, the magnet and the compliance of the surround are very comparable. The HD 599 distorts slightly less in the bass due to a bass tube, which may help with the sensation of bass impact, but both are clearly a level below the HD 660S2 with a larger and stronger magnet and much more compliant surround. Regarding "speed", that is where a lot of people would associate "detail retrieval" or a "fast impulse response". I believe that superior perception of speed correlates with high-frequency extension and smooth treble with natural high amplitude, where a lower mass transducer plays a large role, or potentially less damping behavior of the diaphragm. To my ears, the HD 600 is significantly faster than the HD 599 owing to a much lighter coil and higher lorentz force. Keep in mind that those are just some of my personal observations. At Sennheiser there are many seasoned engineers with much more listening experience and deeper technical background than me, and we can not openly talk about every theory developed internally. At any rate, keep exploring what makes music sound great for you and trust your ears, they're more capable than people think. Kind regards, Jermo

[@evshrug]

Given the very close relationship between the HD 598 and Game One (same transducers), it’s interesting that you hear them different! Of course, the enclosure and stuff inside makes a significant difference… the Game Zero with a similar transducer again sounds completely different. Have you heard the HD 560S/PC38X, which have a slightly different transducer?