Believe that had been the rumour. Nice to know the differences of behaviour between polymer blend and laminate materials, their intended uses and expected results.
We as a team unanimously decided on superior detail retrieval as the raison d'etre for all of our audiophile headphones except the entry-level, and I believe the HD 660S2 is a great representative of that philosophy.
I don't know, what does that mean to you? If you look at the color or size, that's the same.
The acoustic difference between HD 660S and HD 660S2 have mostly been achieved by significant changes to the transducer, which has a markedly different diaphragm, voice coil and magnet chassis, which are the primary components of the motor. I already elaborated on the diaphragm, the voice coil is also new and has an impedance closer to 350 Ohms, and the magnet chassis had to be revised to accommodate the larger excursion. So if your definition of "driver" is different acoustically relevant elements, then this a new driver. From a manufacturing standpoint, it's much harder to build and costs us up to 3 times as much as the original SYS40. To me, those differences make it a new transducer.
The acoustic difference between HD 660S and HD 660S2 have mostly been achieved by significant changes to the transducer, which has a markedly different diaphragm material, voice coil and magnet chassis, which are the primary components of the motor. I already elaborated on the diaphragm, the voice coil is also new and has an impedance closer to 350 Ohms, and the magnet chassis had to be revised to accommodate the larger excursion. So if your definition of "driver" is different acoustically relevant elements, then this a new driver. From a manufacturing standpoint, it's much harder to build and costs us up to 3 times as much as the original SYS40. To me, those differences make it a new transducer.
I don't know, what does that mean to you? If you look at the color or size, that's the same.
The acoustic difference between HD 660S and HD 660S2 have mostly been achieved by significant changes to the transducer, which has a markedly different diaphragm, voice coil and magnet chassis, which are the primary components of the motor. I already elaborated on the diaphragm, the voice coil is also new and has an impedance closer to 350 Ohms, and the magnet chassis had to be revised to accommodate the larger excursion. So if your definition of "driver" is different acoustically relevant elements, then this a new driver. From a manufacturing standpoint, it's much harder to build and costs us up to 3 times as much as the original SYS40. To me, those differences make it a new transducer.
Thanks for the clarification. How does the original HD 660 S driver differ from the HD 700’s driver? Just asking to help further eliminate misunderstandings people may have about the HD 700, HD 660 S, and HD 660 S2 (which you just answered of course).
But taking a little sneak preview, the HD650 and even the HD660S..they are not!....instrument clarity, separation and depth is excellent and the added treble and bass extension completes the window. Looking forward to this evening.: )
The NDH 30 uses the diaphragm of the HD 560S. It's a polymer blend with extraordinary internal dampening, so afterringing after the initial impulse is minimal. At the audiophile team of Sennheiser/Sonova, we have done a multitude of listening tests (also for the HD 660S2) and found that it compromises brilliance and detail retrieval. This is partly because the internal damping is so strong that the initial impulse at high frequencies may not be replicated accurately (it's slightly "blunted"). Instead, we use the laminate material of the HD 800 S, which has slightly higher THD in the bass and more natural decay. Most importantly it accurately reproduces impulses compared to the polymer blend material. Interestingly you can't see that in a frequency response. Even if you equalize the different materials in the same shell for the same treble amplitude, the laminate will subjectively sound as if it had more treble due to the more natural initial impulse response and also possibly due to increased decay.
Ultimately, it's a decision between minimal decay and cleaner bass or faithful treble impulse response, and it's okay to have a preference one way or the other. We as a team unanimously decided on superior detail retrieval as the raison d'etre for all of our audiophile headphones except the entry-level, and I believe the HD 660S2 is a great representative of that philosophy.
Thank you for all this extra information about diaphragms and drivers. I don't know if you can share more information on the Sennheiser drivers used in the Neumann NDH 30. You already mentioned that they use the same diaphragm with the 560S drivers. Are they the exact same drivers or something different, sharing the diaphragm but with Neumann required specifications?
The NDH 30 uses the diaphragm of the HD 560S. It's a polymer blend with extraordinary internal dampening, so afterringing after the initial impulse is minimal. At the audiophile team of Sennheiser/Sonova, we have done a multitude of listening tests (also for the HD 660S2) and found that it compromises brilliance and detail retrieval. This is partly because the internal damping is so strong that the initial impulse at high frequencies may not be replicated accurately (it's slightly "blunted"). Instead, we use the laminate material of the HD 800 S, which has slightly higher THD in the bass and more natural decay. Most importantly it accurately reproduces impulses compared to the polymer blend material. Interestingly you can't see that in a frequency response. Even if you equalize the different materials in the same shell for the same treble amplitude, the laminate will subjectively sound as if it had more treble due to the more natural initial impulse response and also possibly due to increased decay.
Ultimately, it's a decision between minimal decay and cleaner bass or faithful treble impulse response, and it's okay to have a preference one way or the other. We as a team unanimously decided on superior detail retrieval as the raison d'etre for all of our audiophile headphones except the entry-level, and I believe the HD 660S2 is a great representative of that philosophy.
You may not know this but what’s your confidence level that Neumann team uses the exact same driver as 560s or is it the case that the NDH30 drivers are based on the 560s drivers?
I don't know, what does that mean to you? If you look at the color or size, that's the same.
The acoustic difference between HD 660S and HD 660S2 have mostly been achieved by significant changes to the transducer, which has a markedly different diaphragm, voice coil and magnet chassis, which are the primary components of the motor. I already elaborated on the diaphragm, the voice coil is also new and has an impedance closer to 350 Ohms, and the magnet chassis had to be revised to accommodate the larger excursion. So if your definition of "driver" is different acoustically relevant elements, then this a new driver. From a manufacturing standpoint, it's much harder to build and costs us up to 3 times as much as the original SYS40. To me, those differences make it a new transducer.
You may not know this but what’s your confidence level that Neumann team uses the exact same driver as 560s or is it the case that the NDH30 drivers are based on the 560s drivers?
Not to derail the S2 thread....and I can't answer for Jermo...but while we are on driver development.
Believe it has been more or less established that they are built from the same frame, aside from the additional cap any similarities after that only the powers to be can answer, wouldn't mind knowing myself though. All part of the hobby. : )
The original 660 has a nominal impedance of 150 ohms. That is slightly over the typical output impedance of an OTL tube h/p/a. This makes the original 660 a less than ideal match.
Thanks for the clarification. How does the original HD 660 S driver differ from the HD 700’s driver? Just asking to help further eliminate misunderstandings people may have about the HD 700, HD 660 S, and HD 660 S2 (which you just answered of course).
The fast answer is: the driver in the HD 660S and the HD 700 is the same.
The long answer: The older KDH 580 developed for the HD 580 and still found in the HD 600 and HD 650 is to this day mainly hand assembled, which is not ideal for some precision processes, even though it's extraordinarily consistent for what it is. It was optimized for minimal partial vibrations, which resulted in the extremely smooth and clear response which is for me still practically the optimum.
The SYS38 platform was created in the early 2000s to take some of the properties of the KDH 580 into a more affordable space. It shares the same basic geometry in terms of diaphragm and coil diameter, but is fully automated, comparatively slim so that it can be implemented in a variety of headphones and is highly variable in performance depending on the coil or diaphragm used. Since then it has been used in many 500 series headphones, in some PRO headphones like HD 280 PRO, and in our highest performance Bluetooth models like the Momentum 3 and recently Momentum 4. The highest performance version of it sits in the HD 560S, with the new polymer blend diaphragm and a very light aluminium voice coil. This transducer is also implemented without changes in the NDH 30. However, Neumann is incredibly strict on tolerances for this model in a way that it's on the edge of what's possible in headphone series production, which may contribute to positive characteristics like soundstage.
Coming back to your question, the SYS40 platform was originally devised as a peak-performance automated assembly driver to finally surpass the old KDH 580. While our transducers are generally devised to sound good "out of the box" and in many different acoustic systems, the SYS40 has originally been developed for the HD 650 enclosure. This is because we know that it is fairly optimal in aiding a natural listening experience. The advantages compared to our previous platforms are a stronger magnet, a vented magnetic yoke which reduces air turbulence during incursion into the magnet, a very consistent damping concept and lastly an undampened magnet hole. The magnet hole in the KDH 580 is heavily dampened and is drawn out (internally we call it Rüssel, ie. an elephants trunk), so it acts like a bass tube and slightly lifts up the amplitude in exchange for less "punch". So the new transducer would take over the brilliance of the KDH 580, but improve on bass impact and have overall less distortion. When the SYS40 was finished, the plan was made that the implementation should happen in something that visually connects the HD 800 and HD 600 series, in a design that would become the HD 700. While the design had some benefits such as fantastic comfort, overall it was not ideal acoustically, and we all know the end of that story. the development of the HD 660S was basically just putting the transducer into the headphone it was made for.
I don't know all the ideas behind the initial parameters, but they had some requirements like lower impedance for better drivability across devices. With the HD 660S2 we have optimized all parameters for what we think is ideal music playback, ie. much better detail retrieval and more impactful bass.
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