DAB+ sampling rates
are too low
I am not a “Digital Sceptic”; may-
be more of an audiophile or hifi snob. Digital audio from a well recorded CD can produce beautiful sound through a high-quality stereo system. But I am somewhat baffled by the phrase “Listen to that Beautiful Digital Sound” sometimes used to advertise Digital Radio because unfortunately, the audio quality from our Digital Radio Broadcasting system is not necessarily beautiful. I have done extensive listening to DAB, (Eureka-147) in both Denmark and the UK, and found that DAB audio quality is marginally better than AM but not even close to FM.
The main reasons, I believe, are the bit rates of 128kbits/s or lower being used by the majority of stations. Statements by a leading BBC engineer claim that a bit rate of 256kbits/s is necessary for serious music, while 192kbits/s or even as low as 160kbits/s may sometimes be adequate for some types of pop music.
Many complaints from listeners, particularly in the UK, tend to support the BBC statements. But claims by certain officials that the DAB+ (AAC+) system now used in Australia, is twice as good as the obsolete DAB, and therefore allows us to have twice as many radio stations, are utterly uninformed and irresponsible nonsense.
DAB+ is better than DAB but not twice as good. 128kbit/s DAB+ is probably equivalent to 192kbits/s in DAB and is perfectly satisfactory for the majority of commercial radio stations. The 64kbits/s DAB+ used by most of the Australian commercial stations, equivalent to 96kbits/s in DAB, is simply not good enough and nothing to be proud of.
80kbit/s DAB+, as used by ABC Classical, roughly equivalent to 128kbits/s DAB, is something they should be ashamed of, since the DAB+ audio quality is notably inferior to ABC Classical FM. ABC Classical should broadcast at 160kbits/s which will provide the audio quality deemed necessary by the BBC.
I recently purchased a Sangean WFT-1D FM DAB+ hifi component tuner in order to back my arguments. It is a very nice piece of gear. For sound quality comparisons, I listened to some piano pieces while switching between a hifi FM tuner and the Sangean DAB+ tuner.