July 2011 Meeting Recap

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Written by Nicole Levay

July 2011 Meeting  Scott Mason, Showing the Insignia-brand Portable HD Radio

HD Radio

Presented by Scott Mason of CBS

At the July meeting of the LA chapter of the AES, we were joined by Scott Mason of CBS Radio who gave an informative and thoughtful presentation about the iBiquity HD Radio system. 

Scott shared with the group many details on the technology behind HD Radio, as well as his insights on how it is now and has historically been marketed throughout the United States. He was candid in his views of the future of HD Radio on both the AM and FM dials. Mason made it clear that unlike HD Television, there was no direct mandate or implementation plan set forth by the FCC for HD Radio, so the system has had to adapt quite differently. 

Scott began by clearing the air about the meaning of the moniker “HD” for HD radio, and that is that there isn’t one. iBiquity’s original marketing promoted HD as standing for “Hybrid Digital,” but has since changed it so HD stands alone.

HD Radio uses a system called In-Band On-Channel (IBOC) - a method that transmits both analog and digital signals on the same channel or carrier wave. The technology was developed to give a radio station the ability to improve audio quality and more importantly for the FM dial, allow them to deliver additional content within their existing radio bandwidth allocation. While the additional content streams have reduced fidelity when compared to the main channel - HD3 can only broadcast to 8kHz, for
example - the system was recently updated to broadcast in stereo on them.

AM HD Radio signals are processed and managed differently from FM HD Radio signals. The FM band advertises clearer audio quality as well as the ability to multi-cast substations (ex.: KROQ has KROQ HD1 and KROQ HD2 that play additional content that is different from the analog KROQ station.) The reality is that the quality improvements are not nearly as dramatic as the benefit of multi-casting or delivering additional channels. AM HD Radio, on the other hand, trades this multi-casting capability
to instead enjoy far greater enhancement to the signal quality and audio fidelity over its traditional analog signal.

A benefit of the IBOC system is that by broadcasting both the analog and digital signals simultaneously, the receiver has additional flexibility in how it responds to receiving a problematic signal. For example, in areas where reception is poor, the receiver can blend from the digital to the analog signal, rather than have what would usually be a drop-out or complete outage on an entirely digital signal. Further, distortion that is commonly heard as static, multi-path ‘picket fencing’ and other noise ends up
affecting only the analog signal.

This difference in reception was demonstrated by Mason during his presentation on a typical consumer radio receiver. It was immediately evident that the AM HD signal was crystal clear, while the analog signal could not be heard at all. Since both FM and AM bands have the ability to switch between the analog and digital signals, the AM signal would completely drop off as Scott switched to analog-only mode within the Sportsmen’s Lodge building.

In addition to the benefits of HD mentioned above, the FM transmission allows for more information to broadcast on a display, such as traffic and weather reports and photo advertisements. The multi-casting also gives stations additional tools that allow them to focus on more specialized markets as a way to extend a station’s brand. Mason mentioned that HD Radio has also teamed up with iTunes to provide methods for listeners to ‘tag’ a song for later purchase through the program as a way to bring
additional value to users.

Scott confided that he has more faith in the success of FM HD Radio than he does for HD on the AM band. He noted that there are currently 45 stations in LA broadcasting in HD, whereas only around a dozen on AM. While it’s true that most of the market is still listening to analog radio, overall Scott maintains a positive outlook for the future of HD Radio. A key to the success is adoption by the automobile market, and support from car manufacturers continues to grow.

The Society would like to thank Scott Mason for taking the time to share a great presentation and for his informative and candid Q&A session that followed. Thanks to attendees of the July meeting for engaging in a lively discussion about HD Radio.