Nautel and Telos Alliance Eliminate HD Radio™ Time Alignment Drift

Collaborative effort demonstrates industry’s first time-locked signal approach that removes the need for time-alignment devices and correction; new solution leverages existing Made for Radio standards and technologies.

Hackett’s Cove, Nova Scotia, and Cleveland, Ohio (August 27, 2020) –

Nautel and Telos Alliance announced today a new approach to HD Radio™ time alignment, completely eliminating time-alignment issues through locking the FM and HD1 outputs from the audio processor through the remainder of the HD Radio air-chain into the transmitter.

Because HD Radio uses separate but identical streams of audio on the analog and digital channels, these streams can arrive at the transmitter at slightly different times. Diversity Delay – which buffers the analog signal to blend its timing with the digital – is typically employed to ensure that there are no time shifts or artifacts in the signal heard by listeners when their receivers switch between analog and digital. However, minor errors in this time alignment can create audible artifacts, and excessive errors can cause content to be repeated or skipped entirely as the receiver blends from FM to HD1 and back.

“Over the past decade, many vendors have engineered complex solutions with add-on or built-in receivers that generate correction signals to attempt to minimize blending issues,” said Geoff Steadman, Omnia Product Manager at Telos Alliance. “Unfortunately, these solutions can impact the signal by covering up underlying delay drifts. Unlike these other approaches, Nautel and Telos Alliance now have locked the FM and HD1 signals in time so that the time alignment needs no correction, and the blending issues are eliminated completely.”

“Our solution locks the FM and HD1 outputs at the audio processor, and keeps them locked as they pass through the remainder of the HD Radio air-chain right into the transmitter,” said Philipp Schmid, Nautel CTO. “No extra boxes, additional audio codecs, radio receivers or correction methods are needed, and the Nautel/Telos Alliance solution utilizes proven ‘Made for Radio’ standards including MPX, µMPX, and E2X. Our complete solution allows a station’s HD Radio equipment to be location-agnostic – either at the transmitter or the studio – without the need for external time synchronization.”

The solution was demonstrated live during a recent webinar utilizing the Telos Alliance Omnia Enterprise 9s high-density audio processing software, Gen4 Importer/Exporter, and Nautel technology all running on a Nautel HD MultiCast+. “Unlike the fixed-purpose solutions that have become commonplace in the industry, Nautel’s commitment to the open and application-friendly environment of the HD MultiCast+ gives broadcasters a path to new air-chain innovations. Nautel plans to develop products based on these technologies for future release,” said John Whyte, Nautel Head of Marketing.



In the webinar, Nautel announced support on its HD MultiCast+ for the Telos Alliance Omnia Enterprise 9s. Omnia Enterprise 9s centralizes audio processing and virtualizes operation. It’s designed with the flexibility to meet the rapidly changing infrastructure needs of broadcasters as they transition to virtualized environments. 9s is a custom solution for high-density server-based (virtual) systems for customers with a large volume of signals that need to be processed. 

“We’re excited to share these new capabilities with broadcasters today,” said Kevin Rodgers, Nautel President and CEO. “Customers who have invested in or who are evaluating Nautel’s flexible HD MultiCast+ solutions can take comfort in knowing that their investment will support these innovative approaches via software upgrades as they are released in the future.”

The final webinar in the Nautel/Telos Alliance “Radio Air-Chain Innovation” series will be held on Thursday, September 10, and will feature additional live demonstrations of new, disruptive technologies resulting from the collaboration between the two companies.


To sign up for Radio Air-Chain Innovation webinars or view archived webinars in the series, visit


For more information please contact:

John Whyte
Head of Marketing, Nautel
+1 902-823-5174


Krissy Rushing

Director of Content, Telos Alliance

+1 714-261-3030


About Telos Alliance
Telos Alliance is a global leader in audio, trusted by the biggest names in the media landscape. Telos Alliance's focus is to deliver innovative, intuitive solutions that inspire the creation of the most exciting and engaging audio experiences imaginable. No audio challenge is too big; no technology is beyond reach; no solution, large or small, is unobtainable. The Telos Alliance portfolio of brands includes Axia® Audio, Linear Acoustic®, Minnetonka Audio®, Omnia® Audio, Telos Alliance®, Telos Infinity®, Telos® Systems, and 25-Seven® Systems. Headquartered in Cleveland, Ohio, USA, with additional offices and dealers around the world, the Telos Alliance supports the diverse needs of audio professionals around the world with best-in-class support 24/7.


About Nautel

Nautel is one of the world’s largest manufacturers of AM and FM radio broadcast transmitters. Focused on making transmission worry-free for users worldwide, Nautel provides valuable new solutions for digital radio broadcasting at stations of all sizes. All Nautel transmitters employ advanced control, monitoring and instrumentation tools which simplify management of transmitter sites, both locally and remotely via Web access. More than 16,000 Nautel transmitters have been deployed in over 177 countries since 1970.