DAB Radio - Don't believe all you hear
It's bad enough to buy a fancy new gizmo and find it's not what you expect, but when it relays adverts telling you how wonderful it will be, that's really a bit much...
So, what's wrong with this DAB ? Digital Audio Broadcasting was supposed to be the "modern" replacement for FM radio--high quality stereo sound without hiss or interference. And yes, that would have been great! Unfortunately, commercial reality got in the way. Click here for some details, but suffice it to say the following about DAB digital radio::
Audio quality--usually lower than FM radio. This depends on the bit-rate of the station you choose (degradation begins below 256K bps). What's worse, the compression/decompression system is MP2, which is out of date and inefficient. It can end up sounding like a cheap dictation machine (listen carefully to the treble (e.g. cymbals) and see how they sound wrong). To solve this problem, the industry is in the process of changing over to AAC+ system. Unfortunately however, existing DAB radios will not be able to decode this, meaning that over the next few years they will all become obsolete. Great.
Chances of actually receiving it at all--variable. For many people there are some channels where moving the antenna one inch can easily make the difference between good reception and not hearing it at all. My experience is that the DAB radio must be near a window to receive anything much. (The promoters of DAB say it's only a problem in "fringe" areas, but I have had this problem in both Glasgow and Oxford with, by contrast, excellent FM coverage.)
Interference--because the signal strength is so low, for many there's often a background "gurgling" or "bubbling" sound caused by the radio attempting to reconstruct the sound without receiving all of the data.
Ease of tuning--The stations appear in alphabetical order. Great! So, under "B", there's BBC R2, BBC R3, BBC R4... Now, where's BBC R1? Well, it's miles away, under "R" for RADIO 1 (of course) and R5? Try BBC FIVELIVE (comes before BBC R2.) It was a good idea at the time...
To promote this attempt at an FM improvement, a radio advertisement was broadcast claiming that with DAB you can "hear all your current favorites in crystal clear sound". Hearing this on a gurgling DAB radio, with obvious artifacts in the treble, that occasionally lost the signal completely was really too much. Three people complained to the Advertising Standards Authority.
The complaints were partially upheld, with the ASA stating "We therefore considered that not all DAB digital radio listeners would receive “distortion free” and “crystal clear” sound and concluded that the claims were misleading." The ASA did not accept the view that ALL DAB listeners would receive distorted sound due to the compression, but then, whether something sounds distorted or not is a matter of opinion.
To read the full adjudication, click here.
Postscripts
DAB had (and still has) such potential. It is, in my view, a lost opportunity. Maybe one day...
DAB is now being promoted for its ability to record, pause and rewind live radio. At last--a truly useful feature! The only thing I would say is that this technology could be applied to FM radio too. It's true that it's easier with DAB because the signal arrives in digital form, but it would only be "easier" for the manufacturer. The listener would just press "pause" in the same way .
Hot on the heels of DAB is DRM (Digital Radio Mondiale)--a method for transmitting "FM quality" radio alongside existing AM stations. We shall see how well this is implemented...
Finally, my personal recommendation is, if you want lots of radio stations (including almost all of the DAB ones) in good quality, buy a FREEVIEW receiver. It's much cheaper than DAB, has more stations and is better quality. The only problem is the aerial.