The backside of the transducer is identical, but the coil of the S2 is copper coloured, while the 660S had a blue coil.

Hi, thanks for the kind words and great questions. 1. The minimum phase argument may be attractive for people that really like measurements, but I personally don't care for it because it disagrees so much with experiment/experience. If FR really were so important, you could equalise any artifact...

Hi, thanks for your confidence in our team. I believe we'll address this topic in a later episode, but I'm happy to give some background why it's unfortunately not so trivial for us: 1. Burden of scale: Sennheiser/sonova consumer hearing is many times larger than practically all our competitors...

It will be worth it!

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...

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 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...

Hi, thanks for the questions. First, regarding discontinuation: In EMEA and America, the IE 300 has been phased out in favor of the IE 200, as we believe the IE 200 is a superior product for most of our customers. As you may know, Asia's IEM market is much larger, so we'll wait a few months to...

Thanks for the question! Let's clarify the terms first: research refers to working on new technologies that "may" end up in products down the road but have a high chance of failure. Development mainly takes existing solutions and modifies them to create a new product. However, even turning small...

Hi, thanks for the great question. We have transferred production of different product lines over the past six months, i.e. 600 series headphones have been built since summer in Ireland. The team was already incredibly experienced with this product, so we never had better availability before...

We updated the tooling for the 600 family during the time it was transferred to Romania. We reused the space reserved for "Made in ..." for necessary regulatory markings like CE. Since we continue to use the same tooling, the new Irish made HD 600, HD 650 and HD 660S won't have the mark, but...

It's both correct in a sense. Historically, Ireland has always laminated the transducer foils for the HD 800 S. The magic in most of our headphones comes from our patented Duofol-technology, which combines properties of a stiff plastic for brilliance with a polyurethane that provides compliance...

3 years ago there was a strategy of specialization of the plants, ie. intensive manual labor in Romania, high-end products in Germany and automated manufacturing in Ireland. Since then a lot has happened and the two divisions of Sennheiser, consumer and professional, will act independently of...

The plant in Germany will exclusively focus on microphones and wireless systems, Romania will build the affordable microphone products as well as professional headphones like HD 25. Ireland will be the manufacturing plant for most of our audiophile portfolio in the future, except affordable...

Hi yaluen, Thanks for your in-depth questions. I'd be much happier for one of the acoustic engineers to go into detail, but at some point you go into very valuable knowledge. Your first assessment of the IE 800 technology is nearly accurate. The effect is actually worse and harder to account for...

To your question on a source of education: The Loudspeaker and Headphone Handbook by John Borwick is a tremendous resource, but it requires a strong engineering background to appreciate.

They would fit. Our 500 and 600 series headphones have the same chassis size, so you can freely exchange transducers (which is brilliant for tinkering at home :smile: ). A caveat is that the HD 600 and 650 have the transducer chassis combined with the connectors, so there's much more effort...

Hi James, thanks so much! I usually have fit problems with in-ears, so comfort was one of the main focus areas of the team. Even though the sound is our main priority, I'm happiest about how the IE 900 practically disappears in my ears. I hope you have a great time listening to your music!

Thanks a lot! The HD 600 really is an unmatched milestone and one of my most used headphones. But we're working hard to do even better, and there's so much untapped potential.

Happy to help, and great to hear that you got an HD 600. I think it's a headphone every enthusiast should have experience with. Regarding your amp/DAC question, I think we can make our most meaningful contributions in the field of acoustics, but you never know what the future brings. Regarding...

Hi nicnac! Lot's of questions, this is going to be long: 1. Materials: Harder materials have been used in speakers for decades, and we've evaluated the concept thoroughly with the hardest materials available. The takeaway is that no material is "perfect", ie. everything develops undesirable...

Thanks so much for the glowing praise! It's comments like yours that motivate us to outdo ourselves and set our standards higher and higher. I absolutely understand your previous sentiment. I felt it as well. But rest assured that I spend a lot of time reading feedback and suggestions here to...

Hi earmonger, I anticipated comments exactly like yours when I made the decision, which made it really painful to do. Especially because you're completely right and I'd feel the same in your situation. As a little anecdote, I was in a similar situation previously when we developed the...

Hi Vitaly, thanks so much for your kind words and for sharing our enthusiasm for the IE 900! Regarding the cable, you're getting in the right direction. Our goal for the IE 900 was an absolutely flawless signal transmission. That may sound trivial at first, but the MMCX-connector does pose...

Hi, I hope we can introduce engineers at a later date as well. They're brilliant people and awesome to be around (that's why I work here ;)). The tuning reflects the psychoacoustic effect of decreased bass perception at higher occlusion levels. The more open your headphones are, the flatter the...