Why don't some people mind DAB's sound quality?

22nd April 2007

To anybody who knows what good audio quality sounds like, it is obvious that DAB sounds poor and a lot worse than FM. Also, people with a good understanding of audio compression would be able to say that DAB sounds poor without even having to listen to it, because they know that the MP2 audio codec was designed to be used at bit rate levels between 192 - 256 kbps, so the 128 kbps (roughly the equivalent of 72 - 80 kbps MP3) bit rate level used by 98% of stereo stations on DAB in the UK will obviously sound poor -- let alone the 112 kbps bit rate level that Ofcom is encouraging the broadcasters to use.

Yet some people think DAB sounds okay, so this article will look at why some people mis-guidedly think so.

Digital technology is perceived to provide higher quality than analogue technology

If you asked 100 people on a high street which provides the highest quality out of digital or analogue (without being specific about the technology), you would very likely find that 95+ of these people would say digital provides higher quality. The reason for this is simply that the consumer electronics companies have spent literally billions of pounds on advertising over the years to convince us that digital is better than analogue.

Brainwashing via adverts

Three to four years ago the DRDB (Digital Radio Development Bureau -- UK DAB's marketing arm) commissioned a number of high impact advertising campaigns on commercial radio promoting DAB's sound quality, using strap lines such as that DAB provides:

"superb digital quality sound"

Of course, if you asked the DRDB whether they promote DAB's sound quality now they'd say that they don't, and that they only promote the choice of stations DAB offers. The reality is that they don't have to promote DAB's sound quality any more, because every listener to commercial radio has had the "fact" that DAB provides "superb digital quality sound" well and truly drummed into them.

And a more recent DRDB-commissioned advertising campaign for DAB on commercial radio with French & Saunders made out that an FM radio was worth less than a half-eaten out-of-date jar of pickles, and various other highly flattering scenarious that made out FM to be old technology, with the obvious implication that DAB is lovely new high quality technology -- I think you get the picture here.

Although people would protest that they're above being taken in by adverts, the reality is that adverts do work at getting the message across -- or else they wouldn't cost as much money as they do -- and they especially work if the message is repeated over and over again, which was the case for the advertising campaigns making claims about DAB's sound quality.

The psychology of buying

Take the example of a man going into Currys to buy an expensive LCD display. He comes home, plugs it in, and unless it's a very expensive model the picture quality will very likely be a lot worse than that on his CRT TV that the LCD display is replacing, with lots of motion blurring on his LCD that weren't there on his CRT. But ask him whether the picture quality on his LCD display is better than on his old TV he will invariably say "Oh yes, it's far better, look at it, it's fantastic" -- as the football moves across the screen leaving a long white 'vapour trail' behind it.

Basically, when people buy something they try to justify to themselves that they've spent their hard-earned money wisely -- especially when something is considered to be expensive in relative terms. And DAB receivers are expensive in relative terms, because DAB portable radios cost a lot more than analogue radios.

People are loathe to admit they got something wrong at the best of times, but add them spending their own money into the equation and the likelihood that they'll admit that they bought a dog of a product falls to almost zero.

The general public doesn't have a good understanding of digital technology

Unfortunately, the vast majority of people haven't got the faintest idea that the broadcasters have chosen to use bit rate levels far lower than they should be using to provide good audio quality -- the large majority of the population probably won't even know what a "bit rate" is -- and they are therefore blissfully unaware of the fact that DAB could sound far better than it actually does.

This isn't being patronising to the general public, it's just a simple fact that the average member of the public will not know what level of audio quality can be expected from the MP2 audio codec at different bit rate levels -- why would they want to know this?

But when people are made aware of the fact that DAB doesn't sound anywhere near as good as it was meant to sound, and they're told why this is the case, they overwhelmingly want better audio quality than we're currently getting, as can be seen by the following results from a poll on this website (these results are a snapshot of the results taken on 22/4/07):

I've been very surprised by the results of that poll, because I would have expected that people would want at least a few more stations to be provided, but the percentages for the different options have stayed remarkably consistent since the poll began.

I haven't been surprised that 92% of people want higher audio quality to be provided on DAB than is provided at present, however, because I get a lot of positive feedback via this website, and the only people that have had a go at me for what I write on this website actually work in the DAB industry themselves, so I can safely ignore what they're saying...

People confuse the elimination of hiss with better audio quality

Like some of the other points, this sums up the whole issue in a nutshell: people confuse DAB's elimination of hiss with DAB providing better audio quality.

The reality is that hiss is a reception quality issue, not an audio quality issue, and it is the audio quality that is so much worse on DAB than on FM -- assuming good reception quality on both DAB and FM.

The broadcasters and Ofcom know this full well -- one person from the UK DAB industry admitted that they're taking advantage of the public's confusion on this issue -- and they're using it to justify the use of low audio quality on DAB.

There is of course a link between reception quality and sound quality (see the next section), but try telling that to someone with good FM reception quality who has to suffer a large reduction in audio quality on DAB compared to FM.

Those who don't mind the audio quality on DAB are a self-selecting sample

Because DAB eliminates hiss, those unfortunate enough to suffer from poor FM reception are obviously more likely to buy DAB early on, because it should improve their radio reception quality.

Similarly, listeners to AM stations, such as Radio 5, do undoubtedly get better quality on DAB than on AM -- both in terms of audio and reception quality.

Therefore, radio listeners with poor FM reception quality and/or who listen to radio stations on AM are far more likely to buy DAB early on than someone with good FM reception quality and who is perfectly happy with what he or she is getting on FM at the moment. This former group are therefore a self-selecting sample.

People are replacing old and cheap FM radios with new and expensive DAB radios

People are paying far more for DAB radios than they used to pay for FM portable radios. Furthermore, amplifier and speaker technology has improved over the years, so people are usually getting a much better portable radio when they replace an old FM radio with a DAB portable radio.

To be honest, I don't have a problem with DAB on portable radios, because portable radios are incapable of reproducing hi-fi sound due to their size and design, and as such DAB portable radios tend to hide the problems with the sound quality that makes listening to DAB on a hi-fi system so unappealing.

The FM reception quality on DAB portable radios is appalling

I write reviews of DAB/FM portable radios and hi-fi tuners for a magazine, so I've tried out many different DAB portable radios that have FM, and the FM reception quality on the vast majority of DAB portable radios is abysmal -- try this as an experiment: get an old analogue portable radio and a DAB radio that has FM, put them in the same location and tune them into the same FM station and see which has better reception. In my experience, analogue portable radios always provide far better FM reception quality than DAB radios provide.

There are a number of possible reasons for why this is so, such as that the DAB receiver module companies and the DAB receiver manufacturers both obviously have a huge vested interest in DAB being "seen to be" better than FM, because they stand to gain if DAB succeeds, and vice versa. Another possible reason is that because both of the DAB receiver module manufacturers use the same receiver cirtuitry to receive DAB and FM, the circuit will have been designed for DAB, and they're just cutting costs by receiving FM on it.

Personally, I think it's likely to be a combination of both of the above things -- if they wanted to they could make FM reception good, but it would cost a small amount of money to do so, and they don't really want to anyway because they want FM to die off ASAP, and also because neither of the DAB module companies provide good FM reception there's no perceived need for the either to do so.

Conclusions

As I've shown, there are numerous reasons why some people think the audio quality on DAB is okay, but most of these reasons revolve around the general public not having a good understanding of digital technologies, which makes them easy prey for the kind of slick and/or dishonest advertising used to promote DAB.

The unfortunate consequence of this is that the public basically takes what's served up to it and doesn't complain too much, so as far as Ofcom and the broadcasters are concerned, it's job done, and the audio quality issue can be safely swept under the carpet.

Ultimately, UK radio listeners are having to pay for the mistakes made by the BBC, the Radio Authority (the regulators of commercial radio prior to Ofcom) and the commercial radio groups due to them incompetently deciding to adopt the old DAB system.

If the UK had waited and adopted a better digital radio system -- like other countries have done, who will now adopt DAB+ -- the debacle we've had with the audio quality on DAB in the UK would never have happened, because if a more efficient system had been used from the outset then the BBC would never have decided to use such low audio quality as they have done, and that would have led to the commercial radio stations not reducing their quality to such low levels either.

But as the debacle over the audio quality on DAB has happened, those that made the decisions about adopting DAB at the BBC, Ofcom and in commercial radio are only interested in justifying their own decisions, so nothing will be done to improve the audio quality.

For example, the two people at Ofcom that could do something about the audio quality are the Director of Radio, Peter Davies, was part of the team that came up with the BBC's "strategy" for digital radio prior to moving to Ofcom, and the Head of Broadcast Technical Policy, Mark Thomas, who was the person that made the fateful decision to allow the commercial radio stations to use 128 kbps in the first place when he worked at the Radio Authority. So all these two people are interested in is trying to justify the decisions they made in years gone by -- and screw the interests of radio listeners.

And the BBC cannot improve the quality of its stations because its national DAB multiplex is full-to-bursting, so it couldn't increase the bit rates if it wanted to.

So the audio quality on DAB is not going to improve until DAB+ is used, but it will take a number of years before DAB+ has completely replaced the old DAB system once the old MP2 stations have been switched off for good, so the legacy of the incompetent adoption of DAB is going to be with us for a long time yet.

The best advice if you are interested in audio quality is to avoid DAB for the next few years and listen via one of the systems that provides better audio quality, such as FM, Freeview, digital satellite, digital cable or increasingly broadband Internet radio. The Internet will become the highest quality source of radio over the next 12 - 24 months, especially once the BBC iPlayer launches this summer and ISPs convert their networks to support Internet multicasting -- all of the BBC's national radio stations are available at 128 kbps AAC (i.e. far higher audio quality than via DAB) via Internet multicasting, but only a relatively small number of ISPs currently support it, but that number should grow quickly once the BBC iPlayer has launched

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