Anonymous, via text asked:
The big disadvantage of a DAB is the delay. How can we we get the timing right for digital radio?
John - There's no magic answer to this one because there's so much intelligence going on in the audio coding system in order to compress it to 256 or less. In fact, the DAB standard for most stations now is 128 kilobits. There's a lot of sampling of the audio to begin with, to analyse how much can we throw away and still make an acceptable signal. That takes time at the transmission end, but also, it takes time at the decoding end where your set has got to understand what’s going on there. So, fundamentally, DAB is going to be behind analogue, in the same way as digital television is behind analogue television, when it existed of course.
There are two principal sources of delay:
Many "live" programs have a 5 second delay to allow inappropriate content to be scrubbed.
An increasing amount of content is "time-shifted": transmitted at a time convenient to the content producer or distributor, but consumed at a time convenient to the content consumer.
Stereo drift is another problem with DAB broadcasts so much so that genuine live stereo broadcasts are no longer transmitted. The stereo we hear at our end is usually the result of software processing which takes time which results in a considerable delay. If you listen to a genuinely live stereo broadcast on DAB it has the habit of momentarily going mono at regular intervals, it has I believe something to do with the way bit rates are fed from the the mics to the AD converters on the DAB transmitters. RE.Craig, Mon, 11th Feb 2013