Sennheiser Spectera: Broadband bidirectional digital wireless ecosystem

In Amsterdam, Sennheiser has showcased its most innovative solution for wireless digital audio transmission, Spectera. Designed with WMAS technology (Wireless Multi-Channel Audio Systems), Reduces wireless system complexity, while increasing capacity, enabling time-saving workflows, and offers full remote control and monitoring.

In IBC 2024, Sennheiser has ushered in a new era in the Wireless digital audio streaming with the introduction of what it calls the world's first bidirectional broadband solution: Spectera.

With technology WMAS (Wireless Multi-Channel Audio Systems), this solution from Sennheiser, Brand Distributing Magnetron, greatly reduces wireless system complexity, while increasing capacity, enabling time-saving workflows, and offers full remote control and monitoring, including permanent spectrum detection.

Features two-way pocket units that manage IEM/IFB Digital Signs and mic/line at the same time. It is resistant to RF fading and allows flexible use of the wideband RF channel, for example, for digital IEMs, with a latency of up to 0,7 Milliseconds.

"Our broadband solution will be ideal for large productions, whether in the field of touring, Broadcasting, the theater or any other area that requires multi-channel audio setups. Spectera meets the main wants and needs of our customers in terms of ease of use, Operational reliability and flexibility. Offers less hardware, drastically reduced frequency coordination, redundancy and the flexibility of an ecosystem that grows with its needs", Co-CEOs Say Andreas and Daniel Sennheiser.

Powered by WMAS

Two-way digital broadband transmission addresses many of the typical challenges that users, Wireless Audio System Operators and Owners Experience. These include complex frequency coordination and complicated rack cabling for a large number of channels, and the large space still occupied by a multi-channel wireless system (in the warehouse, On tour and backstage), both for the space and for the amount of time required for charging, Download and Setup.

Sebastian Georgi and Jan Watermann are the inventors of Sennheiser's specific approach to WMAS. The technology they developed is a proprietary variant of OFDM-TDMA, Purpose-built for trusted communication, multichannel, Bidirectional and low latency.

They succinctly compare this broadband approach to standard narrowband technology. “Instead of many narrowband RF carrier frequencies of 200 individual kHz, We use a single wideband RF channel for audio transmission; Two-way transmission of audio and control data, to be more exact”.

In Sennheiser's approach, Broadband RF channel is a TV channel of 6 or 8 Mhz, according to local regulations. The WMAS system organizes your audio links within this channel. To each audio link, either a microphone or an IEM, You are assigned specific time slots to transmit your audio information; for the first time, it is possible to have IEMs and microphones on the same TV channel instead of two channels separated by a guard band.

"Thanks to the fact that all audio links use the full width of the RF channel when it's their turn, RF fade is greatly reduced. This corresponds to a diversity of 40 times for an RF channel of 8 MHz and 30 times for a TV channel of 6 Mhz. In addition, Spectral density is low, making it easy to reuse frequencies, for example, at a larger festival venue, between neighboring theaters or in a broadcasting complex", Georgi and Watermann add.

Reduced system complexity

One of the biggest innovations in the Spectera ecosystem is the Base Station, what, in a single rack unit with 32 Tickets and 32 Outputs, replaces a rack full of wireless microphone receivers and IEM transmitters. An entire production could be accommodated on a single wideband RF channel (6 or 8 Mhz).

Smaller unit size applies to beltpacks, that simultaneously manage microphone/line and IEM/IFB requirements. "Having a single flask is not only a great advantage for artists, but also facilitates the work of the sound engineer, that has a unique type of flask and can, if necessary, quickly add an IEM to a microphone. Storage also becomes less complex, with a single Base Station and two frequency variants (UHF and 1G4) for flasks and antennas", comments Bernd Neubauer, Spectera Product Manager.

The future of wireless professional audio is two-way

Spectera represents a change in control and monitoring. Not only does it offer a return channel, but continuous two-way communication at all times, for a truly complete remote control. Through the permanent control data flow, Audio settings can be adjusted, Adjust IEM and microphone levels, monitor battery status and RF status, and much more. AES encryption 256 (AES CTR mode 256 with maturity of >10 000 years) For both audio and control data, it ensures the necessary data privacy.

In addition, All units help to continuously detect the spectrum, meaning they scan for potential interference from other RF sources. With Spectera, It is possible to see 'behind’ of the RF channel that is actually being used and detect interference.

Audio quality

Spectera delivers Sennheiser's signature digital audio quality for Microphones, In-ear instruments and monitors (IEM), using different audio codecs optimized for applications, all of them processed in-house with precision of 32 Floating Bits.

Eleven audio link modes allow for flexible control of audio quality, Latency, the number of channels and the operating range of each audio link, so that the operator can always use the RF channel to the fullest, either giving high quality to fewer audio links or allowing more links and reducing the quality accordingly.

Regardless of which audio link mode is selected, Spectera delivers a very clear sound, That which “will be a revelation especially for IEM users”, explains Neubauer. “With Spectera, you get impressive clarity and accuracy of digital IEMs with ultra-low latency of up to 0,7 Milliseconds. Dual mono drive ensures clean separation of in-ear channels, Improving the soundstage for optimal performance”.

Benedikt Euen, Spectera Product Manager, Adds: “Spectera respects spectrum resources by allowing IEMs and microphones to be on the same TV channel. It also simplifies frequency coordination between engineers at festivals and allows for faster workflows. For example, If a big band is waiting for their concert at a festival, it will only be necessary for them to deactivate the sound of their RF so that the entire band is in the air".

The main components of Spectera are the rack-mount base station, SEK Bodypack and the DAD antenna.

The rack-mount base station is the heart of the Spectera ecosystem and is a real space saver. Supports up to 64 Audio Links, I mean, 32 Tickets and 32 Outputs, in a 19" format and 1 Or. One base station supports up to two channels of RF broadband. Base station is frequency independent; Activating the corresponding local license for the base station will automatically load the authorized frequency ranges.

Redundancy has been key in the design of the base station. It has two power supplies, Primary and secondary Dante connections, two slots for optional redundant MADI connections (optics or BNC) and four antenna ports, that not only allow redundancy, but also synchronized and extended antenna zone coverage or increased system capacity through the use of additional frequency ranges. The unit's cascading ports will be activated with a future firmware version. Note: no RF components on the base station, so there is no interference with other wireless equipment in the rack.

SEK Bodypack with microphone and IEM

SEKs are also space-saving because the same beltpack can handle both IEM and microphone or instrument requirements, And this can be determined and changed flexibly during a show.

The flask has a 3 Pins for a lavalier or headset microphone (select from a wide range of acclaimed Sennheiser models) or an instrument cable (like the IQ 1-4). The headphone jack 3,5 mm connects to Sennheiser's range of professional in-ear headphones and features a high-power headphone amplifier with impedance matching. The SEK is equipped with a persistent display, where device information is retained on the screen even when a unit is turned off.

The bodypack is available in a UHF frequency variant (470 – 608 MHz and 630 – 698 Mhz) and 1G4 (1350 – 1400 MHz and 1435 – 1525 Mhz). It is powered by a BA rechargeable battery 70 (the same as for Evolution Wireless Digital) and can offer up to seven hours of runtime depending on the configuration selected.

DAD Antenna

The DAD antenna with IP protection 54 It's a Transceiver antenna that manages mic/line signals, EMI signals and control data at the same time. The antenna carries the RF components of the system, eliminating the need for amplifiers, Dividers and Combiners.

RF is digitized here, therefore, the DAD antenna does not use a BNC connector or coaxial cable for connection to the base station, but an RJ connector 45 reinforced and a CAT 5e cable, that are much easier to handle, more cost-effective and not prone to cable losses like coaxial cables. The antenna is powered by the base station via PoE.

Here, The operator can flexibly choose between audio link modes with their different audio quality levels, latency, Possible audio and reach links, as well as full remote control and monitoring of the entire system, with visibility into all audio settings and RF statuses.

"Setting up a multi-channel wireless system can also be a real challenge from a software standpoint. Therefore,, We introduced support behaviors to make system management as fast and intuitive as possible. LinkDesk also stores productions, so operators can quickly retrieve their system configurations and save time at the event.". Smart notifications offer additional assistance.

LinkDesk software also manages base station activation through single-node-based licenses. By entering the specific local license code, The software ensures that the system operates within local regulatory requirements for frequencies, RF channel bandwidth and transmit power, giving operators a secure position when it comes to compliance.

"Spectera will not only revolutionize multi-channel wireless audio, but it will also open up many new opportunities", says Andreas Sennheiser. "3D immersive audio is one of those opportunities. Thanks to its synchronized word clock for all RF audio, Spectera will be the first solution capable of capturing phase-coherent wireless audio for immersive recording and playback.". "With the new workflows that this ecosystem facilitates, We will undoubtedly see new creative uses of wireless audio technology.", concludes Daniel Sennheiser.

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