The future of theatre sound

The modernized sound system in the Markgrafentheater Erlangen

Bühnentechnische Rundschau

During six weeks of conversion work in the 2019 summer break, the Markgrafentheater in Erlangen had a 3D audio system installed that can be used in parallel with the classic sound system. One of the first municipal theatres in Germany to offer real 3D sound, it hopes to extend its new, improved sound system in the future by technology to prolong reverberation time and a 3D tracking system.


It all started about three and a half years ago, when a director wanted to have an actor equipped with a microport to stand at the rear of the stage with his back to the audience and quietly murmur his lines – and for every member of the audience to hear it as if the actor were sitting next to them. Attempts to achieve this effect with our previous surround speakers proved disappointing. So, in the end, we built six additional speakers into the chandelier in the auditorium. In this way, we at least came close to creating the desired effect. The director’s idea and the complicated process of realizing it, making many compromises along the way, was the trigger for a period of intensive research into immersive audio.

We started attending as many trade fairs and conferences as we could, to find out about and compare the relevant manufacturers’ immersive solutions. We also had the opportunity to test a lot of different speakers and mixing desks, some on site in the Markgrafentheater, allowing us to make direct comparisons with our house system. Gradually, we got a more concrete idea of what it was we needed.

Planning and research

During the project’s planning and development phase we went to the Fraunhofer Institute for Digital Media Technology (IDMT) in Ilmenau to gain an impression of how the SpatialSound Wave System works. The chief engineers also came to the theatre itself, and we talked to the sound department at Opera Zurich, where the same system is being installed. Its installation in a listed building, a historical theatre with balconies and boxes, presented some very specific challenges.

As SpatialSound Wave (SSW) technology is designed to manage any number of speaker types and positions, we could continue using existing material and just supplement it as required – with the added advantage of reducing costs.

This allowed us to keep the entire Meyer Sound front and stage PA. All the existing parts of the Nexus router were checked by Stagetec and renewed where necessary. Considering Nexus’s sound characteristics and flexibility, it made sense to extend the existing infrastructure rather than replace it.

The new system

In addition to the existing PA, for which we altered the speaker positions, a total of over 80 speakers were built in circular formations on four levels in the auditorium and supplemented by ceiling speakers. The main challenge here was to guarantee a comparable result at every seat, not only in the stalls but also in the balconies and boxes.

We increased the frontal amplification by adding Meyer Sound UPA 1P in the gantries right and left, about 2m over the stage floor, and adjusting the position of the central speakers. The sound from the stage edge also needed to be completely reworked. Here, as in the apron, seven L-Acoustics X4i are now integrated to ensure a comparable result even when the orchestra pit is raised.

The theatre now uses a CRESCENDO-T Platinum mixing desk by Stagetec and the existing Nexus network has been supplemented by a Star router, an additional base unit, various input and output cards and a Dante connection. All the new L-Acoustics speakers are connected to three Dante-controlled Innosonix-MA32/D power amps with 32 channels each. All the EQs are stored there. The speaker arrangement and the attendant level differences are controlled by the 3D audio-rendering engine.

Better locating and spatial, lively sound

As we cater for regular guest performances and rentals as well as our own productions, it was important for us to be flexible for these scenarios, too, and to have the option of offering a conventional sound concept.

The new system allows us to generate object-based 3D audio by wave field synthesis via the Premium 3D audio-rendering engine SARA II (Astro Spatial Audio). Up to 64 audio-objects can be freely placed and moved simultaneously in real time by their x-y-z coordinates. SARA II is controlled via Dante’s CRESCENDO-T direct outs.

A crucial advantage, especially for theatrical use, is the improved sound locating. Especially when it comes to amplification using microports, discrepancies often arise between the actors’ actual positions, or where the spectators visually perceive them to be, and how they are acoustically located. The planned addition of a 3D tracking system that can compute the actors’ positions and send these metadata to SARA II is set to make the listening experience even clearer.

Even if the 3D system is only used as a front system for static musical presentations, it offers audible advantages over channel-based replay. The sound is spatially equalized as it is conveyed via several different speakers. The focus of the sound can be matched to the actual sound sources and stable, spatial, lively sound generated relatively simply. Unlike with conventional stereo sound, which of course also makes it possible to generate a certain spatial depth by means of panning, delay, EQ and echo, the plasticity created by the object-based approach can be experienced not only in a relatively small sweet spot but across a distinctly larger area of the auditorium.

A pioneering project: first reports and a conclusion

Installing the system in a historical, listed theatre with stalls, three balconies and boxes, was a special task. The office for monument protection was consulted on all the visible measures, regarding the size, colour, number, positions and wiring of the speakers. At first glance, you hardly notice that 80 new speakers have been installed.

In general terms, the new system can be used amazingly intuitively. Thanks to the many options for transmitting sound that the system makes possible, we can try completely new approaches in many situations. The first premiere in the new season, an evening of songs with a live band, featuring dozens of playback units and microport amplification, demonstrated the new system’s huge potential and even garnered positive mentions in reviews.

Now we need to explore the scope of the system. There are barely any limits to what you can do any more – even the most outlandish direction can be implemented with its help. This new toolbox is virgin territory for all of us; there are so many possibilities to explore and become familiar with. Since the conversion work was done, the theatre has far more sophisticated sound technology that can serve as a great foundation for all sorts of sound concepts for us to develop in the future. Plus, the Astro Spatial Audio System with integrated stage-tracking and reverberation time extension holds additional potential.

Because although the auditorium has very good acoustics, they are relatively dry, and could benefit from more volume for the theatre’s regular concerts. But thanks to all these new possibilities, there will certainly be plenty to look forward to in Erlangen.


BTR Ausgabe 1 2020
Rubrik: English texts, Seite 222
von Hans-Christian Fuss and Christoph Panzer

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