It is impossible to avoid the D-word these days. ??Digital?? is being slapped in front of everything ?? cameras, televisions, phones and even photocopiers. Why? Because lazy marketing people hope we will be convinced that everything digital is brighter and better than everything that preceded it. This is a distinctly dubious proposition.

Nowhere does the ??digital rules all?? argument become more murky than in radio. For the past year, the BBC has been in the vanguard of broadcasters anxiously trying to push us into upgrading to new radio sets that are designed to receive digital audio broadcasting (DAB) stations. They have promised us a brave new world of ??crystal-clear reception?? ?? that??s because digital radio never hisses, apparently.

Yet what about the sound? My car went digital a few weeks ago after a ??350 Blaupunkt Woodstock DAB 53 radio was installed. This suddenly gave me access to several new stations from the BBC, among others, and some existing terrestrial ones, such as Virgin, that are unavailable on FM in my part of Kent.

The sound was clear, as you never experience conventional interference, but on many stations it was also flat, narrow and decidedly lacking in oomph. On Radio 2 FM, Wogan had enough breadth in his voice to rattle the bass range of my speakers. On DAB, he seemed distinctly muted and down in the mouth.

The truth is that, depending on your personal tastes, DAB can seem a bit of a swizz. After kicking off the new medium with high-flown promises of ??CD quality??, the broadcasting industry has opted to fill the airwaves with as many stations as possible while reducing the quality of sound from your speakers to less than that of many a cheap pocket MP3 player.

For digital radio, the audio signal is compressed before broadcasting ?? in other words, parts of the sound are removed in the hope that you will never notice what??s missing. The problem is that, according to Dr David Robinson, who wrote a paper on DAB while an academic in audio engineering at the University of Essex, most digital broadcasts in the UK are being compressed so much that they sound worse than their FM counterparts. The website Digital Radiotech (www.digitalradiotech.co.uk), a constant and sometimes controversial thorn in the new industry??s side, goes even further, claiming that Britain now has the lowest-quality DAB anywhere in the world.

The technical reasons make grim reading. DAB compresses signals with a system known as MP2, the less efficient predecessor of MP3, which has become the standard file format for music that people play on handheld players. The less music is compressed, the better it sounds ?? so a higher bit rate, measured in kilobits per second (kbps), means better quality. Robinson says that at 256kbps, MP2 will sound much better than FM. At 192kbps, the quality adopted by the BBC in the early days of DAB, he expects it to be ??almost always?? better than FM, though today, Radio 3 is the only UK station to broadcast at this standard. Then the figures fall off badly.

In the UK, most DAB listeners are now subjected to sounds that Robinson regards as ??usually worse than FM??. Of the 50 stations that Londoners can receive, half broadcast at 128kbps and 20 at a much lower standard, many of them music stations. Only three national DAB stations come close to matching the MP3 audio quality of an iPod, usually 160kbps, and that is still half the rate needed to match the sound of the original CD.

Even Radio 3 ?? ironically, the BBC??s least popular terrestrial station ?? has to drop from 192kbps to 160kbps when Five Live Sports Extra and Radio 4 Long Wave are being broadcast. Radio executives, who once boasted of ??ear-shattering?? quality improvements, have stopped making any promises, except that DAB is ??crystal-clear and digital??.

Do listeners notice? The industry??s trade body, the Digital Radio Development Bureau (www.drdb.org), says not. It points to a survey of 3,000 DAB listeners, 95% of whom said that they were satisfied with sound quality.

Rachell Fox, liaison manager for BBC Radio and Music, is equally adamant that today??s audio standard is acceptable, maintaining it is the range of stations that persuades people to turn to DAB. ??The BBC has a responsibility to serve all its diverse audiences,?? she said. ??We believe we have found a balance between launching new radio services and good sound quality. Recent research shows that most people are satisfied with the sound quality, with about 95% of digital radio listeners rating it ??excellent??or ??good??, or saying they were ??satisfied??. The steady stream of repeat purchases also indicates listeners?? satisfaction with DAB ?? 15% of current sales are to listeners who already own a DAB radio.??

One early adopter of DAB is Andy Norman, an IT contractor from Surrey who bought one of the first receivers, a Psion Wavefinder, and was initially delighted with the results.

??It was a great improvement over FM, providing high-quality sound and no interference. At home, I listen almost exclusively to Radio 4. Its audio quality on DAB is awful now ?? so low that it doesn??t sound much better than an AM transmission. It??s most noticeable in speech, where it causes distracting sibilance. For me, the extra choice of stations does not make up for the quality issue.

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