RF FAQs in Sennheiser Systems

RF FAQs in Sennheiser Systems | Hoang Bao Khoa

06/10/2025 9 4.6/5 in 2 votes

Have you ever wondered why Sennheiser chose to develop wideband WMAS technology instead of traditional narrowband wireless microphones? Or how Spectera can transmit multiple audio channels within a single TV channel while maintaining excellent stability and minimal interference?

Which Bandwidths Does Spectera Support?

Spectera operates on either 6 MHz or 8 MHz bandwidth, depending on regional regulations and local frequency infrastructure.

How Many Frequency Ranges Do You Plan to Deploy?

The SEK module and DAD antenna are currently available in two versions: one for the TV-UHF band and one for the 1.4/1.5 GHz band. The base station can be used for both since it contains no RF components. Additional frequency ranges may be supported in future firmware or hardware revisions.

Does Sennheiser's WMAS System Occupy an Entire TV Channel - Is That Spectrum Wasteful?

In practice, multi-channel systems achieve the highest efficiency when used for at least four simplex channels. For more complex or duplex applications, WMAS is actually significantly more spectrum-efficient. Both IEM and MIC can operate within a single TV channel. Refer to the technical document “Why Use Wideband” for more details.

What Is the RF Transmission Power?

The maximum RF transmission power reaches 100 mW EIRP, though it may vary depending on national regulations. In controlled environments, power can be reduced to optimize spectrum reuse.
Because the system uses a TDMA mechanism, only one device transmits RF power at any given time.
Moreover, the signal is distributed evenly across the entire bandwidth, meaning WMAS has a significantly lower spectral power density than narrowband systems with the same number of transmitters.

Is There a Plan to Support Operation in the 800 MHz Duplex Band?

Not at the moment. Due to limited available spectrum in the 800 MHz duplex range, deploying WMAS in this band is not currently feasible.

What About the 700 MHz Duplex Band?

The 700 MHz band is not licensed for wireless microphones and is instead allocated for other types of applications depending on national frequency regulations.

How Long Does RF Channel Switching Take?

RF channel switching takes less than 10 seconds for the system to return to stable operation. Future versions may include an automatic frequency hopping feature.

What Is the Purpose of the Four Antenna Ports?

These ports allow for expanded coverage, increased redundancy, or the setup of a second RF channel to optimize performance.

How Many Antennas Should I Use?

This depends on your specific RF environment - such as coverage area, expected interference levels, and physical conditions.
Tests show that in indoor environments with good reflections, one antenna may be sufficient. However, in outdoor areas or locations with strong absorption materials, using two or more antennas helps stabilize the RF link and reduce dropouts.

Sennheiser Spectera – Two-way Audio Transmission System Overview