Congratulations on winning the Grammy! You recently won in the Best Dance/Electronic Album category. In my view, 3-D Der Katalog is a groundbreaking spatial sound project, employing Dolby Atmos and its virtual 3D implementation on headphones. Fritz Hilpert and Tom Ammermann took on the roles of 3D mix engineer and 3D mastering engineer respectively, and received a Grammy nomination in the Best Surround Sound Album category in 2017.
You previously worked with d&b on your first 3D sound projects. Were you able to use the experience you gathered there for the Dolby Atmos mix process or was the Dolby Atmos mix a new beginning?
Playing live we used d&b’s newly developed Soundscape system. We’ve gathered experience with 3D live sound during many of our concerts over the last few years, and that influenced the development of the new system.
The Kraftwerk live DVD Minimum Maximum was also mixed in 5.1 for the DVD, and was also available as an audio-only multi-channel version on SACD. That was in 2005, when that format offered the best possible quality in multi-channel audio. But as we have often seen in the history of technology, it didn’t gain wide acceptance. The SACD version of “Minimum Maximum” is one of the most sought-after collector’s items.
The Atmos mix builds on a surround mix but adds a whole new spatial dimension, bringing with it a new way of perceiving the music. On home systems, that uses two or four overhead channels that are arranged in an imagined semi-sphere above the audience’s heads. These are either addressed directly or using the so-called objects, which in addition to the third dimension is what’s new about Dolby Atmos. Channels defined as objects can be moved around in 3D letting you create diagonal movements through the room, say, from below front left to overhead rear right.
Fundamentally, there are no rules in electronic music about locating the sound sources. That’s not the case when working with classical music recordings or even traditional band projects. But Minimum Maximum was more about reproducing a live concert using direct signals from the stage as well as sonic information from the venue. We dispensed with all that for 3-D Der Katalog, which focuses on the best possible audio source quality while incorporating active sound manipulation happening on stage. That made the way the spatial characteristics of sounds were integrated into the mix more open. But the rule for both our live sound and Atmos mixes was that the rhythm part arrangements shouldn’t be disrupted or even destroyed by the time lapses involved. That means that the rhythm elements aren’t distributed willy-nilly around the room, only to be heard in a very narrow sweet spot, if at all. That’s not so much of an issue when mixing for Atmos home systems, but when producing 3D sound at a concert venue that becomes a danger given the long distances involved.
In those scenarios, pad sounds, electronic voices and other non-percussive sounds work best. That sounds like there are a lot of limitations at play. But there’s still plenty of creative latitude available, especially if you immerse yourself into this topic, for example by studying how best to position reverbs in a multi-channel system.
The film industry is currently bringing new films onto the market employing Dolby Atmos. But music productions in this format are still few and far between. Does that make it difficult to find a standard or norm for your own music? After all, there’s hardly any reference material out there.
Breaking into territory that was more or less uncharted made the project even more interesting. Your own vision of how to build a 3D mix that also uses the third dimension isn’t hampered by pre-existing approaches. It’s still hard for the proud owners of 3D speaker installations to find music in 3D. The people at Pure Audio are making a contribution by offering a special catalog for HD and 3D sound. But at the moment a lot of progress is being made by offering cheaper amplifiers or interesting soundbar products that use up-firing systems, obviating the need for mounting speakers in the ceiling. The treble frequencies are projected to the listener via the ceiling, which of course in this case should not be dampened. It works surprisingly well and is also used to project sound side-ways.
On the production side, Steinberg has also made provided a path to mixing for Atmos through the release of Nuendo 8. This makes it possible to open Cubase projects in Nuendo and from there connect directly to the Dolby RMU, letting you access the “object” approach to mixing. On the playback side, the objects are sent to the Atmos Decoder and then routed to the specific system configured with X speakers, up to Atmos Cinema playback on up to 64 speakers.
We recently had the opportunity of experiencing the first-class quality and production of the Dolby Atmos system at a cinema screening of Katalog and I was very, very impressed with the sound, but also by the 3D visuals.
Despite all the possibilities and ways of manipulating sound and the freedom to position it anywhere in the space, I never got the impression that it was gimmicky. I found the mix open and transparent. Do you ever find yourself in danger of losing your way amongst all those possibilities? Are there differences between mixing for cinemas and Blu-ray? What compromises have to be made?
Fundamentally, mixes intended for consumption at home also work in cinemas. There aren’t any compromises there. On the contrary, the auditory experience in cinemas is the maximum of what you can currently imagine. That’s why we made a few changes at the ARRI@Bavaria mix stage. Some movements of sources through space were adapted to suit the larger room in terms of their tempo and style. Because cinemas offer a standardized listening level, you can work specifically with that level in mind. You don’t have to factor in the fact that the sensitivity of human hearing for a set of frequencies changes with the volume at which they’re heard. Generally speaking, large rooms can handle more bass, and they should be supplied it. During the film you might experience low-frequency turbulence so you should keep your seatbelt fastened at all times.
I’ve seen the band live several times and as far as I can tell you seem to use reverbs quite extensively, and manipulate them in a purposeful way. That was also my impression on hearing 3-D Der Katalog. Large reverbs were placed behind the listener, for example. Does that also work on surround headphone mixes?
Definitely. We used Spatial Audio Designer (SAD) by New Audio technology (NAT) for the headphone surround 3D mixes. We also used that for mixing the Dolby Atmos bed in Pro Tools and Nuendo. NAT is a software company run by Tom [Ammermann], who brought his years of experience in the surround and 3D worlds into this production. We used the SAD to translate the finished Atmos mix using NAT’s high-quality HRTFs to virtual studios without losing the impact of a good stereo mix. On the contrary, they strongly mirrored my 3D mixes. The perception of front/back/above/below works astoundingly well on the SAD system even when using normal stereo headphones. As always, the quality of the headphones plays an important role. Using a set that provides good resolution will help the listener to hear the little details. But you can even attain an astoundingly good sonic experience with some regular ear bud-type headphones.
The Kraftwerk albums 12345678 were released under the title 3-D Der Katalog on Blu-ray, DVD and CD. This includes the eight classic Kraftwerk albums Autobahn (1974), Radio-Aktivität (1975), Trans Europa Express (1977), Die Mensch-Maschine (1978), Computerwelt (1981), Techno Pop (1986), The Mix (1991) and Tour De France (2003).
All eight albums were filmed and recorded between 2012 and 2016 (3D world tour) at famous venues such as MoMA (New York), The Tate Modern Turbine Hall (London), Akasaka Blitz (Tokyo) and Sydney Opera House.
The Krakftwerk sound seems to be finely honed. But there’s still enough room for improvisation and sound manipulation so that every concert sounds a bit different. Electronic sound generators are seen as perfect, perhaps even too perfect. Is that a motivation for adding little inaccuracies and modulations?
It’s definitely not our aim to disrupt the sense of perfection by adding inaccuracies but we do try to incorporate spontaneity into the music. The term modulation is a better description. The basic tracks are very transparent and clearly structured, so sometimes small variations are enough to change the sound. The fact that we are playing live is also important here — as are the “analog vocals”! There has been an interesting development, as these days perfection is seen as a flaw, while back in the ’70s and ’80s “this sounds like the record” was meant positively.