Digital Radio well and truly dysfunctional.
Discussion
Looks like the british version is going down a blind alley. Virtually all stations are now compressed to 128KBps or worse and no alternative codec can be used to get the sound quality back up to that of the FM stations. The company that developed the "PURE" DAB reciever Chip didn't put in any upgradability into the chip in it's efforts to "create" the DAB market. It also runs the DAB network, (if I read it correctly), And the ARCAM reciever was the only one out there. Hence fund the development of the cheap radio and create the market. Trouble is that chip is in thousands of DAB radios and to "update" means making them useless. For the full story look up a copy of Hi-Fi World. (PS It's very handy for the latest Computer Audio as well).
telecat said:
Looks like the british version is going down a blind alley. Virtually all stations are now compressed to 128KBps or worse and no alternative codec can be used to get the sound quality back up to that of the FM stations. The company that developed the "PURE" DAB reciever Chip didn't put in any upgradability into the chip in it's efforts to "create" the DAB market. It also runs the DAB network, (if I read it correctly), And the ARCAM reciever was the only one out there. Hence fund the development of the cheap radio and create the market. Trouble is that chip is in thousands of DAB radios and to "update" means making them useless. For the full story look up a copy of Hi-Fi World. (PS It's very handy for the latest Computer Audio as well).
I just found this via a more recent posting which linked to this one.
Can you provide more details of where you heard this "story"? (Which edition of Hi-Fi World?) I ask because it's wrong in so many ways I don't know where to start correcting first.
~70% of DAB radios (including the Pure ones) use a single chip DAB decoder from Frontier Silicon called "Chorus":
www.frontier-silicon.com/products/chips.htm
"The Chorus FS1010 is a super-integrated, ultra low power single chip digital radio baseband IC with extensive on-chip peripherals and optimised for Eureka-147 Digital Audio Broadcast decoding. It is programmable and flexible based on the revolutionary multi-threaded META™ DSP and general purpose processor core from Imagination Technologies. This programmability also makes it an ideal solution for forthcoming mobile TV standards such as T-DMB."
The same DSP can be found in some Freeview (DVB-T) decoders, among other things. In fact I've seen demos of Chorus simultaneously decoding and displaying a freeview TV broadcast along side it's normal DAB decoding duties.
Many of the Pure DAB radios are capable of receiving firmware updates via the USB port (eg "The Bug" has had an update to enable the Electronic Programme Guide I believe). The first generation of Evoke-1 radios did not have the USB port though, and as far as I know are not capable of having the firmware updated "in the field". They're all based on the Chorus chip though. [If] the DAB standard were to introduce an alternative audio codec, there is no technical reason why Chorus could not be used to decode it.
Pure do not "run the DAB network", and they have no control over the codec used. They just sell radios capable of receiving DAB transmissions. (They were involved in some trials of broadcasting 5.1 channel surround sound a while back though - a Pure radio was used to receive the signal).
They were instrumental in establishing the DAB market in that they were the first company with a sub-£100 DAB radio.
Disclaimer: I work for Imagination Technologies, but not Pure (radios bit), or Metagence (DSP bit), so don't take any of the above as any sort of definitive statement
Jim
I put a Blaupunct Dab head unit in my car as I could not receive FM( a common fault with my car which even when working as it should is apparently not brilliant reception anyway.)
Overall I am happy with it. I now recive more stations than I ever did with FM in any other car I can get virgin for one example. Yes the quality is not CD quality but its ok.
on the whole I'm happy I got it. yeah real CD quality would be nice after all thats what the were talking about when all thi sdigital thing started.
Overall I am happy with it. I now recive more stations than I ever did with FM in any other car I can get virgin for one example. Yes the quality is not CD quality but its ok.
on the whole I'm happy I got it. yeah real CD quality would be nice after all thats what the were talking about when all thi sdigital thing started.
Parrot of doom said:
It means that DAB is still technically very poor compared to FM, and is not a suitable replacement technology.
Bet you get real tetchy when the guy playing the trombone in the 3rd row back scratches his arse in the quiet bits at the start of Beethoven's 5th...
Seriously though, some people would listen to FM and DAB and say DAB is "better" because of the lack of hiss. Others wouldn't be able to stand listening to DAB because all they can hear are the artifacts introduced by the codec used.
FM has its own artifacts though. Most FM stations are "compressed" (in an analogue sense - the difference between loud and quiet is reduced). A DAB signal is capable of conveying the full dynamic range of the source material though. (Most radios have the options to do dynamic range compression though - it's handy when listening in a noisy environment as you don't have to turn it up in the quiet bits only to be deafened in the noisy bits).
There are some other areas where DAB could claim technical superiority over FM radio.
Nationwide DAB multiplexes (groups of stations transmitted in a single bitstream) are broadcast on the same frequency everywhere, so there's never a need to retune your car radio as you move from one area to another. (FM has a coping mechanism for this via RDS, but it's far from perfect). The need to put FM stations in adjacent areas on different frequencies makes for very inefficient use of the available radio spectrum as well.
DAB provides program information (with some radios featuring an Electronic Program Guide), an accurate time signal (no need for the "pips" any more), and a vastly improved range of stations (listed in alphabetical order so they're easy to find, with no need to even know what frequency they're broadcast on).
No, it's not the last word in audiophile quality (certainly not with the low bitrates some stations transmit at), but for the vast majority of the radio listening public, it's plenty good enough, and comes with some nice improvements in usability. (Some people still listen to LW you know
If you want higher bitrates, there's always radio via freeview/satellite. I think there are even audio only freeview decoders now.
Jim
Well I reckon its content that will win it for DAB in the end. As Jim points out FM is not always that brilliant anyway.
Anybody wanting CD quality music will buy the CDs. For the rest of us listening to the radio is something we do while engaged in other things such as driving or pottering around the house.
Therefore pure sound quality is not an issue but finding the stations with the right content, the stations that are broadcasting the kind of programs we as individuals wish to hear is essential in this day and age.
So I guess the future of DAB is assured. Arguments about technical issues will be for nerds and geeks just like to the old CD verses vinyl or VHS against Betamax type of debates. Meanwhile the rest of us will simply get on with using the technology for our own entertainment.
Anybody wanting CD quality music will buy the CDs. For the rest of us listening to the radio is something we do while engaged in other things such as driving or pottering around the house.
Therefore pure sound quality is not an issue but finding the stations with the right content, the stations that are broadcasting the kind of programs we as individuals wish to hear is essential in this day and age.
So I guess the future of DAB is assured. Arguments about technical issues will be for nerds and geeks just like to the old CD verses vinyl or VHS against Betamax type of debates. Meanwhile the rest of us will simply get on with using the technology for our own entertainment.
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