DAB is really a solution in search of a problem rather than something that is an attractive replacement for FM radio.
It offers practically no advantages to end users and adds a whole lot of problems, costs and unnecessary complications.
Here in Ireland, DAB services were launched by the national public service broadcaster, RTE, but no commercial stations have shown any interest in the project and in general won't touch it with a barge poll. They prefer to retain their existing FM infrastructure.
Advantages of DAB:
1) Single frequency network vs FM's different frequencies in different areas.
2) Electronic programme guides / live text information.
3) More stations into the same amount of spectrum as FM
NB: Many of these advantages are provided by analogue FM services using the RDS (Radio Data System). This allows car radios to automatically tune to the strongest transmitter on national/multi-transmitter local FM services, provides programme information text, traffic reports services etc etc.
Disadvantages of DAB:
1) Complex and expensive broadcast system
2) Requirement for stations to share a multiplexes rather than have their own FM transmitters. This leads to issues with creating a telco-like monopoly to manage broadcasting.
3) Complicated reception equipment which is often bulkier, more expensive and much more power hungry than a simple FM receiver.
4) Poor audio quality is often experienced due to over-compression of signals or poor signal quality. Instead of a slight hiss like FM, this causes a 'bubbling mud' sound.
5) Lack of availability of receivers. Because DAB is so unpopular there hasn't really been a huge interest from manufacturers in creating equipment. So, it's still rather niche and specialist.
6) Lack of integrated receivers e.g. in mobile phones, mp3 players etc.
Commercialisation problems:
1) Lack of control and independence of infrastructure - local and national stations in Ireland at present own their own FM networks. They may share broadcasting sites, but they are entirely independent and don't have to rely on an infrastructure provider.
2) Local stations don't like the idea that other larger local stations might suddenly become available nationally.
3) Large-scale investment required to change broadcasting infrastructure and advertise new services.
4) Very small community stations and rural commercial FM stations might be wiped out if they had to re-invest in duplicating their FM broadcast networks.
5) Risk of losing customers who know the station by its dial-position. Many Irish stations call themselves by their FM frequency e.g. Dublin's 98, 104fm, Midlands 103, Cork's 96fm, Cork's RedFM 104-106, Newstalk 106-108 etc etc
6) Poor choice of receivers.
7) All of the indications so far are that consumers don't seem to warm to DAB and adoption rates are very poor, even in markets where the Public Service Broadcaster has really pushed it e.g. the BBC in the UK.
So, overall, I think DAB is just digital dogma i.e. digital for the sake of digital. Unlike Digital TV, it doesn't really offer consumers with something better, easier to use with more choice.
I would see some sense in using FM subcarriers to allow stations to broadcast extra digital services.
DRM (
Digital Radio Mondiale Digital Radio Mondial ) is also showing good prospects of use on AM (Medium Wave and Longwave). This could provide near-FM quality and stereo on AM services which cover large areas / are used for international broadcasts.
