DAB+ and DAB – the differences, and its use in the UK

What does a DAB plus signal actually do, and can we see the UK changing over to DAB+ in the future?

• Want a less technical answer? Try What is DAB+ - also here on media.info

In the comments of a story on an old blog of mine, Scott posts:

James, I have learnt that in the UK, they are evolving into DAB+ from DAB while most of European countries are using DAB+. What are the major differences? Thanks!

Since Scott asked, here's a quick primer about DAB+, updated for 2017:

A DAB audio signal is encoded in MP2 (the ancestor to today’s MP3 format). A DAB+ audio signal is encoded in aacPlus (strictly, aacPlus HE v2). Your iPod uses AAC as standard; aacPlus uses a number of clever techniques to make it more efficient, so audio sounds better at lower bitrates. Roughly, 48kbps DAB+ sounds the same as a 128kbps DAB signal.

A DAB+ audio signal also includes slightly better error correction, which might mean a reduction in 'bubbling mud' or other problems in poor reception areas.

Apart from that, there are no differences. DAB+ and DAB use the same transmitters, same multiplexing equipment, and so on, and DAB and DAB+ signals can happily live on the same DAB multiplex. A DAB+ radio will also happily decode DAB signals as well (although a DAB radio won’t decode DAB+). Almost every DAB radio on sale today will cope with DAB+ automatically, or will prompt you with instructions on how to upgrade (which could be as easy as typing a code in, or downloading some new firmware).

Any radio with a Digital Radio tickmark will receive DAB+ without any problem. If buying a DAB radio, you should ensure it has the Digital Radio tickmark somewhere on the packaging: it ensures it'll sound as good as it can, and has other benefits in terms of performance.

DAB+ is now the standard way to launch new DAB services, and is in use in, among other places, Australia, Norway, Switzerland, Belgium, Germany, The Netherlands, and many more. The main benefit is that you can get many more channels onto a typical DAB multiplex.

In the UK, the new national multiplex contains a few DAB+ services, including Fun Kids, Magic Chilled, Union Jack and Jazz FM. Everything else on that multiplex, however, is standard DAB. DAB+ services are also available on some small-scale multiplexes, including London, Portsmouth and Manchester.

So, that done, let’s put a few facts straight:

The UK has no plans to move from DAB to DAB+

While DAB+ services are now appearing in the UK, there are no plans to switch the majority of radio broadcasting over to DAB+: not yet, anyway. There have been a lot of DAB sets sold in the UK. DAB sets are in over half of all households here, and generally we don’t replace radios as fast as any other entertainment equipment (like a TV, a set-top box, or a mobile phone). Given this, it’s unlikely that the UK will be switching to DAB+ any time soon, and there are no plans to make that complete change. That doesn't mean that individual stations won't make the switch, though.

The UK could learn from Denmark, who is completing a switch from DAB to DAB+ later in 2017.

DAB+ doesn’t automatically mean better audio

Some of the main proponents of DAB+ in this country want it because they think it’ll result in better-sounding audio, in comparison with DAB. It might not. Many DAB+ countries use 48kbps aacPlus, and the new services on the SDL multiplex are at 32kbps: they offer a good stereo signal, but they're still not a brilliantly clear sound. The main benefits to radio listeners from DAB+ will be additional choice, not enhanced sound quality. That said, DAB+ normally means stereo is available at bitrates formerly only used for mono.

DAB+ doesn’t always mean cheaper costs for broadcasters

Changing to DAB+ instead of DAB doesn’t make the transmitters any cheaper (and, actually, makes them slightly more expensive since there's a patent to pay to Fraunhofer). Broadcasters are charged for the bitrate they use, but most DAB multiplexes in the UK aren’t full. Multiplex owners will still want to cover their costs.

The UK is currently only using DAB+ when it's the only way to get onto a multiplex. If there's 128kbps spare, it may make more sense to launch an old-fashioned DAB service, since you're likely to be able to be received by many more listeners. However, as DAB+ sets become more popular, this won't always be the case.

DAB+ is the only sensible choice if you’re launching digital radio now

If you’re launching digital radio in a new market, it makes no sense to be looking at standard DAB. DAB+ is robust, reliable, and comparatively cheap, particularly if you consider the opportunities of launching over 20 channels on one multiplex. Receivers are cheap, power-efficient, and available now. The technology is tried and tested. Broadcast radio, free at the point of consumption, has significant benefits over internet radio.

There are lots of reasons to go with DAB+ for a new marketplace. For the UK broadcaster, however, there are few benefits to move over to DAB+, and plenty of reasons not to do so yet.