Interview with Sennheiser’s Chief Headphones Designer, Axel Grell

To audiophiles, Axel Grell doesn’t need any introductions. One of the world’s top headphone engineers, Axel led Sennheiser’s audio design on such legendary products as the Orpheus system, HD 800 headphones and IE 800 in-ear monitors. NXT’s contributing editor Chester Tan caught up with Axel during the recent CanJam Singapore 2018 to speak about the revolutionary new Sennheiser HD 820 headphones, which incorporates Gorilla Glass to reduce unwanted vibrations.

Chester Tan and Axel Grell

Q: How did you come about deciding to design the HD 820?

Open type headphones are better by principle because sound that is radiated by the diaphragm to the rear can leave the system and the sound that is reflected from the ear can also leave the system. So, this is why Sennheiser built open-type headphones, while building closed-type headphones for specialised users like musicians, DJ. But we never had a closed-type for audiophiles.

All these while, the high-end consumers in Germany seem to be happy with open-type headphones as they usually have a dedicated listening room. But we listen to feedback from colleagues in Hong Kong that consumers would like to listen to music without disturbing people around them. This is the motivation behind the HD820.

In addition, Asian consumers tend to be very serious when it comes to music details. They want to listen deeply and hear everything, to get as good a sound as possible. We also got the same feedback from the sales team in Japan and Singapore. We find that it is important to listen to our customers to understand what they really need. So, here is the solution.

Q: So it sounds like the HD 820 is designed for the Asian market?

Yes, to a large extent. It will be sold worldwide, but the highest demand has always been in Asia.

Canjam Logo

Q: Why the use of Gorilla Glass transducer cover instead of other materials?

We wanted to have something lightweight, stiff, and transparent because we have great drivers and we don’t want to hide it. Like the Audi R8 with glass engine, we are proud and wanted to show it.

Q: How does the HD 800S compare with the HD 820?

The first impression of the HD 820 is that it is driving more towards low frequencies. Upon deeper comparison, the HD 800S achieves wider sound staging, while with the HD 820 the instruments sound closer but still wider than usual closed type headphones. With the HD 820, we want to give the open type headphones experience to the listener.

The approach to designing these two headphones is similar, and both aim to deliver natural reproduction with good externalisation.

I really like to listen to Daft Punk on the HD 820. Their music is surprisingly good for analytical listening. With a pair of good headphones like the HD 820, you get the low frequency push.

For orchestral music, I prefer to listen with the HD 800S, delivering better instrumental separation and imaging.

Q: When did you realise you wanted to develop closed type headphones?

It occurred to me that I was looking for closed type headphones when my children were younger and I could still hear the music from their HD 580 Jubilee headphones even with the bedroom doors closed. And that was the birth of the HD 280 PRO, the first closed type headphones I designed. In fact, turn the numbers around, and you get the HD 820. And we sold tons of HD 280 PRO for musicians.

NXT Singapore is the official media of Canjam Singapore 2018.