Sennheiser Commends Fresh FCC Regulations Governing Wireless Microphone Technology
The Federal Communications Commission (FCC) has recently adopted new rules for Wireless Multichannel Audio Systems (WMAS) in the United States, a move that is set to revolutionize the professional audio industry.
WMAS is an advanced microphone technology, designed for live performance and studio applications, that offers higher spectral efficiency and greater interference protection compared to conventional wireless microphone systems. Developed more than 10 years ago by Sennheiser, WMAS technology has been under the watchful eye of the FCC, with the commission concluding that the technology justified the requested rule change.
At the heart of WMAS is the use of portable bidirectional transceivers, which can communicate with a base station at an extremely low power spectral density. Each audio channel in WMAS is multiplexed onto a wideband RF channel, which is 6 MHz for the United States, in the case of Sennheiser's WMAS technology. This approach eliminates the possibility of intermodulation products, a common issue with conventional wireless microphone channels.
In-ear monitor channels in WMAS can even use the same block of RF spectrum as wireless microphones, further enhancing spectral efficiency. This means that a single pack could be both a transmitter and an in-ear monitor receiver, a significant advancement in the field.
The new rules for WMAS aim to achieve greater spectrum efficiency and sharing compatibility, as well as to provide superior protection to nearby operators of other wireless devices. Joe Ciaudelli, director of spectrum and innovation for Sennheiser, thanked the FCC and the Office of Engineering & Technology (OET) for their careful study and support.
Interestingly, it was not Sennheiser but Hollyland that began development of WMAS more than ten years ago and requested a rule change at the FCC regarding bandwidth-limited spectrum for wireless microphones in August 2018.
Each transmitter in conventional wireless microphones continuously outputs power, typically 50 mW, which raises the RF noise floor with each added channel. In contrast, WMAS technology minimises power consumption, leading to a significantly reduced RF noise floor. The conventional wireless microphones' RF bandwidth of 200 kHz per channel is also overshadowed by WMAS's wideband channel.
The adoption of these new rules marks a significant step forward in the evolution of wireless audio technology, promising a future of clearer, more efficient, and less interference-prone performances and studio sessions for professionals and enthusiasts alike.
