Crave Talk: Why digital radio still can't beat FM
We've all been told by advertisers that DAB radio offers a superior listening experience to FM. But is this actually the case? We've taken a look at claims that FM is superior, and the truth is surprising
The choice offered by DAB made me fall in love with digital radio, but now we've reached the third date things have gone a bit Mexico. DAB's begun to slur its words, and there's something suspicious going on under all that makeup. The fear has set in. It's time to get DAB to pull its act together before I dump it for something better.
DAB radio was sold to us as a revolution in radio listening; a chance to abandon our crackly analogue sets and upgrade to a flawless digital signal. It might shock you to learn that many DAB broadcasts sound worse than the same station on FM, providing you have a good signal. Despite the high claims for this technology, DAB has failed to deliver the quality of sound that audiophiles hoped for. What went wrong?
The hole in the heart of digital radio is something called bit rate. We measure the quality of a digital audio signal in terms of how many kilobits of data are used to describe each second of music, and this is known as the audio's bit rate, or fidelity.
If you find this hard to visualise, imagine a pianist playing a piece, say Mozart playing a concerto to an audience in the 18th century. When Mozart plays the piece normally, the audience can hear every note -- every key Mozart plays. If someone in the audience counted how many notes Mozart was playing, he might average around five or six notes each second.
Now imagine that the King tells Mozart he must play the same concerto again, but never play more than three notes each second. The audience would still recognise the piece, but the detail and richness of the original performance would be lost.
On a microscopic level, this is exactly what's happening to the music you hear on DAB radio stations. Instead of the music you hear being described by 256 or 192 kilobits of data per second, it's often being described by as few as 80. Considering that a passable MP3 is -- in my opinion -- 192Kbps and only a handful of the top DAB stations (such as BBC Radio 3) broadcast at this rate, we're looking at a pretty sad situation for listeners that value quality as well as choice on the radio.
DAB radio broadcasts aren't currently good enough to do justice to even a mid-range hi-fi separates system -- leaving many audiophiles extremely disappointed. Listening to a 256Kbps MP3 on our hi-fi reference system is immeasurably better than DAB and listening to a CD shows a staggering difference between Radio 1's DAB broadcasts of a song and the original recording. Side-by-side comparisons of music on digital radio and then on CD demonstrate just how far the format still has to go before it can begin to match its claims of near-CD quality sound.
There is a solution to this problem, and that's for UK broadcasters to increase the bit rate at which they transmit music. Although channels share a limited transmitter bandwidth, there are several viable proposals to reduce bandwidth slightly on talk radio and increase it on music stations.
For this to happen we have to kick up a fuss. Broadcasters won't voluntarily upgrade their equipment. Are you with us, or against us? We're taking names for the bit-rate revolution -- let us know what you think of the oppression of audiophiles by Big Radio. -Chris Stevens