Getting to know Spectera, the Sennheiser revolution

Sebastian Georgi and Jan Watermann, R&D engineers at Sennheiser and inventors of the Wireless Multi-Channel Audio Systems (WMAS), convey all the keys to Spectera, the great revolution for the world of audio that the European company has presented for the first time during IBC 2024.

A few days ago, Sennheiser presented to the global industry one of its best kept secrets; a project in which the company's R&D teams have worked intensely to respond to some of the main challenges of the industry broadcast, Live y ProAV. We talk about Spectera, two-way broadband solution which greatly reduces the complexity of wireless systems at the same time increases its capacity.

Spectera was born to make possible flows of more versatile work thanks to your permanent spectrum detection while offering, in parallel, a full remote control and monitoring. In addition, beyond providing resistance to RF fading, it provides flexible use of the broadband RF channel, which yields a Latency as low as 0.7 milliseconds on digital IEMs. These technological advances materialize in the form of bodypacks bidirectional capable of managing microphone/line signals y IEM/IFB digital signals at the same time.

Sennheiser Spectera - Revolution - Interview

Sebastian Georgi (left) and Jan Watermann (right)

The system is completed with Spectera SEK, solution that manages audio microphone, IEM and control data on the same broadband channel, and a complete base station single rack unit with 32 inputs and 32 outputs which helps replace the classic rack full of wireless microphone receivers and IEM transmitters. Everything, working around WMAS, a variable of OFDM-TDMA Designed specifically for multi-channel, bi-directional, low-latency communication in professional audio environments.

In this interview, Sebastian Georgi y Jan Watermann, promoters of WMAS and Sennheiser R&D experts, allow us to know all the details of how it was forged Spectera, what elements differentiate of other similar solutions on the market and in what specific ways it can help industries such as mercado broadcast.

Spectera: a disruptive approach

With Spectera, Sennheiser launches a highly innovative approach to digital wireless systems that already exist on the market. What challenges have you identified in this area and how does Spectera address them?

Sebastian Georgi (SG): Spectera's starting point is a very specific problem in today's systems: frequency selective fading. The thing about current systems is that you have a nice setup of antennas. Everything works fine. Then, you walk 10 meters on stage and experience a drop in signal power, which can lead to audio dropout and a show interruption. And this happens regularly, especially in large places where there are many reflections, such as a room with a metal ceiling or walls, causing destructive interference. We found the solution to this problem by applying a broadband approach.

We approached this problem in a fundamentally different way: we wanted to address frequency interference using a wideband signal design to, instead of occupying 200 kHz, occupy 8 MHz. Likewise, to achieve similar or better efficiency in terms of frequency resources, we had to make the divisions otherwise. So, unlike what happens now, where each microphone has its own frequency and is placed on the spectrum, we divide these resources over time. In this way, each microphone has its fspecial time slot. This is still technology TDMA, which is well known on television and in 4G and 5G systems. However, what we have done is adapt this general-purpose technology to some very specific requirements of professional audio, such as audio quality and latency.

During the presentation of Spectera, Andreas Sennheiser (CEO) put on the table how complex the situation is regarding the radio frequency spectrum. How does the new system address this issue?

Jan Watermann (JW): We have different audio modes, so that each user can design the system to adapt it to your needs. This way, if you only have one channel on the television, you could now put on more channels. For example, some modes provide higher efficiency and consume less spectrum by combining microphone and monitoring inEar. This approach is achieved by using a single RF device, which requires less spectrum and is easier to deploy. It's also suitable for touring: if you arrive at a new facility, just check that the previous day's channel is free. Otherwise, you just have to look for a free channel and change the frequency.

Of course, because it will not be the same to deploy the system in Australia, in the Americas or in Europe...

(SG): We have opted to offer a new approach regarding the specific variants of each country. We decided not to make variants for each territory, so the hardware will be the same. The user will acquire a license which will be delimited by each country. For example, in the United States you will be able to use 6 MHz of bandwidth, while in Europe it will be 8 MHz. In this way, users will be able to adapt to the different regulatory regimes of each country.

The advantages of bidirectionality and open standards

Spectera is built around its ability to perform broadband two-way digital transmission. How does this technology help reduce the complexity often associated with large-scale audio installations?

(SG): "Think about current systems. It gives you a receiver to in ear to her talent and sends her to the stage. As of this moment, there is no information. What is the condition of the battery? What volume did you decide to use? You have no control over the unit, making you basically blind. He hopes that everything will go well, but he has no certainties. On Spectera, all devices are bidirectional, meaning that even if you use the device solely as audio receiver, you can continue transmitting control information and even monitor the battery status or volume. You can even adjust volume remotely if the talent has accidentally changed it to an inappropriate level. All of this provides a lot of control over your environment. Also, as I mentioned, setup time is drastically reduced thanks to the frequency coordination.

WMAS is the concept that makes Spectera's proposal possible. What does it consist of?

(JW): WMAS is mainly the name of the licensing system. After preparing the technology, we created our first prototypes, but we had to go to the authorities to authorize us to use these broadband devices. In fact, all systems today use 200 kHz, which is the de facto standard for wireless microphone systems. So first we had to add this proposal WMAS in a way masked to the standard and, now, we already have permission to offer these products.

(SG): WMAS is not a technology. There are many people who think it is, but it is just a chapter part of a standard of the ETSI. But there is one very important thing, and that is that this chapter is completely neutral. He OFDM-TDMA It is an open standard that can be implemented in any technology you want and this is positive, since other agents could have different ideas of how to implement WMAS to provide more options to customers.

Spectera and the challenges of broadcast

In the future we will be able to find Spectera on tour, in theaters or on television. Particularly, in the broadcast area, what type of applications do you imagine to take advantage of its full potential?

(JW): In the broadcast market, Spectera will stand out for its flexibility, starting from its receiver bidirectional. In the most typical case of news programs, you normally have two devices: one for system microphone and a second for the monitoring or the IFB. With Spectera, this can be done with a single device, simplifying processes and making different scenarios more flexible. Also, for example, you could change the entire remote configuration to adapt to each need or format.

How could Spectera be integrated into new IP environments with the SMPTE ST 2110 standard?

(JW): Currently, Spectera has two ports MADI and interface Dante, but we are already planning to be able to integrate connectivity in the base station with the standard SMPTE ST 2110.

(SG): The current solution is compatible with SMPTE ST 2110, but there are some limitations. We know that there are many broadcasters who want to have deeper integration, so we will invest in this in the near future.

Many technical managers are always concerned about the transition to a new system, especially when it comes to innovative technologies. How would the arrival of Spectera affect traditional audio systems?

(JW): The Spectera system can be used in conjunction with current systems. You can plan a deployment slightly separating the frequencies, which could even make a traditional system and Spectera work seamlessly. joint. There is no need to change the system at once: you can start using it with the microphones and, in the future, make a complete transition.

When will Spectera be available?

(SG): We will be able to give more details in the first half of 2025.