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Broadcast phones and the Full-HD audio treatment

The telephone is an important but problematic tool for broadcasters. The main drawback is it always sounds like a phone. But, as Kevin Hilton reports, new technologies are changing that and could make the ubiquitous mobile the only thing needed for general communications and live location reporting.

The history of technology rests on ongoing development and improvement. This traditionally happened over considerable periods of time but in the digital age it can take only a few years before something new comes along to replace a pioneering system. The next possible example of this could be HD Voice, the wideband telephony technology that has brought better clarity and audio quality to voice over IP (VoIP) communications. As well as finding favour in general telecoms, broadcasters are now adopting HD Voice for talkback and live reporting. HD Voice is based on adaptive multi-rate wide-band (AMR-WB) codecs delivering 7kHz or 3.5kHz audio bandwidth on 3G networks. This is considered good enough quality for voice only but new coding technologies are being used to push it further. German research institute Fraunhofer IIS has added its AAC-ELD (Advanced Audio Coding enhanced low delay) codec to the basic system to produce Full-HD Voice, offering a full spectrum up to 20kHz. While Full-HD Voice has been adopted by Apple and Android (pictured), use of the original HD Voice system and the number of countries where it is available are increasing. According to a list published during February by the Global mobile Suppliers Association (GSA), territories now offering commercial HD Voice services include: Australia, Austria, Belgium, Canada, the Czech Republic, Denmark, France, Germany, Italy, Poland, Russia and the UK. Among the professional broadcast manufacturers marketing equipment based on HD Voice is Glensound Electronics, which produces the GS-MPI004HD broadcasters’ portable mobile phone and GS-MPI005HD rackmount unit. UK broadcasters using HD Voice include London commercial station Capital Radio, which uses it for live reporting, and BBC Bristol, where all sports reports are now based on it. Glensound’s sales and marketing manager, Marc Wilson, says the company initially regarded talkback in OB trucks as the main application for HD Voice but when reporters saw it they had other ideas. “I think of HD Voice in terms of the iPad,” he comments. “People didn’t know they needed it until they got one.” Wilson does not view HD Voice as a replacement for ISDN, saying it is something else entirely. “It’s a single channel mono service and as the applications we’re dealing with are just based on voice, then 7kHz is fine. The people who have been using our systems have been able to make HD Voice work in situations where nothing else was getting through.” Research engineers at Fraunhofer, however, did see the 7kHz bandwidth as a limitation. Stefanie Frank of the audio and multimedia real-time systems division says that because the full range of human hearing extends to 20kHz, what HD Voice produces is barely half of what can be heard. Fraunhofer IIS’s AAC-ELD algorithm has a lower delay than the original AAC technology, which, says Frank’s colleague Matthias Rose, makes it better suited to communications work. Full-HD Voice is already used for video conferencing and has been adopted for the Apple iPhone, iPad and Mac computers but Fraunhofer wanted to push it further into the mobile sector. “Mobile World Congress seemed the place to start bringing this technology to the telephony world and Android is one of the two most used platforms for mobile phones,” Frank comments, explaining the demonstrations of Full-HD Voice on Android phones using a LTE (long term evolution) 4G network at the recent MWC. Broadcasting is seen a major area for Full-HD Voice, with manufacturers including Telos already incorporating it into systems. “Contributions and live reporting are applications that can take advantage of the high audio quality it produces,” observes Frank, “and we do see it as a replacement for other technologies where IP-based connections are being used.” Marc Wilson does not rule out Glensound producing Full-HD Voice systems but says at the moment there are no plans for this. “The situation is quite fluid and we are responding to what broadcasters are asking for,” he says. “All this is still quite new and the existing HD Voice on 3G is solving problems right now.”