DAB

DAB radios and tuners have been released for around about five years. Along with improved sound quality, DAB promised more information for what is being broadcasts, and no re-tuning. DAB broadcasts are currently available to 65% (rising to 85%) of the UK's population. The amount of DAB broadcasts you can pick up will vary greatly on your location.

While DAB manufacturers did promise near CD quality, so far it has not always lived up to expectation. Certainly, the naysayers, predicting the demise of analogue tuners, have exaggerated the impact of DAB.

Some audiophiles claim that the UK DAB signal quality is not a patch on FM. One problem is that many DAB broadcasters are only transmitting in mono and not stereo sound.

The signal length on FM is lower, but with a decent outdoor aerial it can outshine DAB. This is largely due to broadcasters transmitting DAB at a low bit rate, and this is what determines the sound quality.

The original mission of DAB was to improve upon the level of fidelity, noise resistance and interference offered by FM. For DAB broadcasts to improve upon FM transmissions, it would ideally be transmitted at 256 or 224 k/bits/s.

Once it becomes broadcast at 192 kbit/s or lower, the MPEG Layer 2 audio codec (which DAB uses) is inadequate, and audio quality is compromised. When the DAB bit rate is 128 kbit/s for stereo, it is officially inferior to FM.

It's estimated that over 95% of DAB broadcasts are currently inferior to FM. One exception is BBC Three, which is broadcast at 192 kbit/s. However, even the BBC tried to save on bandwidth costs, and temporarily lowered the bit rate to 160 kbits/s.