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Digital radio is more than fulfilling its promise of a minor broadcasting revolution, with early bonus stations delivering additional content, and full-power transmissions now reaching most of Australia's state capitals.
ABC's one-weekend-only channel 'ABC Woodstock' was a prime example of how smart programming can capture new niche audiences. Delivered in full quality only on digital radio, and at lesser bit-rates via internet streaming, ABC Woodstock's home page was loaded with comments from listeners wanting to know how they could "buy" a download or CD of the extended documentary format. You can't buy it, dudes; it's an example of the enjoyable transience of high-quality radio broadcasting.
So far we have only three potential complaints about digital radios. They are:
a) no integrated in-car dash units available... Pure's bolt-on Highway is a poor substitute; Blaupunkt seems best placed to get the first true integrated unit to Australia;
b) we're still assessing if the broadcast quality is suffering from broadcasters splitting their allocated bit-rates too thinly among their extended services;
c) the issue of audio latency. DAB+ broadcasts are emerging from digital radios up to five seconds after their analogue counterparts. This causes a problem for the many radio fans, you have several radios around the home playing simultaneously, in bedroom and kitchen for example. If you introduce a digital radio to this environment, it's like living in an echo chamber.
Of course, if you're listening to a single digital radio, the delay matters little unless you are paranoid your Swiss chronograph no longer hits the 'pips' spot on the hour. But it makes simulcast listening - to radio sports coverage while watching on TV, for example - impossible. Presumably it also means the end to radio studios monitoring their output directly off the air, so spotting any transmission problems immediately.
While the latency issue affects both ABC and commercial stations, we approached Commercial Radio Australia for their comment on the issue, and CEO Joan Warner was so forthcoming on the details, it is useful to quote her reply in full, with our thanks - it seems the latency won't be going away, though they'll be aiming to keep it as low as possible.
From Joan Warner, CEO, Commercial Radio Australia:
"There are a number of separate causes of delay in the DAB+ digital radio chain from the studio to the multiplexer site.
"Audio encoding delay – 0.3 seconds. (this is the delay for the encoder to turn audio into DAB+ audio.
Service Multiplexer Buffering delay – 0.4 seconds
Service Multiplexer error protection delay – 0.2 seconds
Ensemble Multiplexer Buffering delay – 0.8 seconds
Ensemble Multiplexer error protection delay – 0.8 seconds
Transmission interleaving delay – 0.768 seconds
"This means that DAB+ digital radio should come out of your speakers of your radio just a little over three seconds after leaving the studio.
"However, some broadcasters currently have their audio buffering delays set higher than this – so delays at present may be greater. The industry is aware of this and is working to reduce the delays on all services to the lower figure of around 4 seconds - but it will take a little time.
"Currently 5AA in Adelaide and Skysports in Sydney have a latency of about 3 to 4 seconds so people can watch a football game or race with the radio commentary as close to time as it is possible to get.
"When walking from a room with an analogue radio into a room with a digital radio there will be a delay. Jez, we just have to get all of those analogue radios in the house replaced with digital, so there’s no comparison!”
More info: www.digitalradioplus.com.au
Story: Jez Ford
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