Is there a surround audio processor in your future? Without a doubt, say industry leaders Orban and Omnia Audio. But if you're expecting something like a five channel version of your current stereo processor, think again.

The on-air surround processor of tomorrow? Probably not.

Processing for 5.1 surround will become a must-have, says Greg Schulke, sales and marketing manager for Orban Labs, because broadcasters transmitting a digital signal in that format will want to maintain a consistent product while drawing surround content from different sources. But achieving the practical realization of such a product will require "entirely new algorithms."

Omnia Audio's Frank Foti agrees. Any processing of the 5.1 signal has to pay close attention to correlating channels dynamics in order to faithfully preserve the spatial imaging present in the sound field. The change will be almost philosophical in nature for many broadcast engineers because the surround environment, by its nature, eliminates the current imperative for stereo loudness. "The need for aggressive gain reduction is just not there," says Foti.

While neither manufacturer will say for sure exactly when they intend to introduce a surround processor, development is clearly on their minds. "We're not going to ignore it," Schulke said in a brief interview, "but there has to be sufficient demand to justify the R&D costs—it's the chicken and egg syndrome."

Foti's outlook was similar, if a bit more specific. "It's going to take about 18 months to two years for surround to move into the broadcast market...right now the product field is very limited, [oriented] mostly toward TV."

Nevertheless, momentum for 5.1 surround radio broadcasting for FM IBOC is already building among forward-looking broadcasters. These people realize they'll have to compete for audience with audio streamers wielding the same technology in the very near future, as evidenced by Orban's streamed 5.1 demonstration at the Surround 2004 exposition in Los Angeles in September. Seemingly in answer, Fraunhoffer demonstrated a 5.1 surround HD Radio hardware demo at the NAB Radio Convention in San Diego. Can surround processors really be far behind? Time will tell.

Processor mock-up inspired by Omnia Audio and Orban