The Ten Myths of DAB

[Resurrection Man]

It sounds a bit like "mythical" 35mm film. The difference between this and DAB is that consumers relished the benefits of chemical-free photography, but don't see any benefit in changing to an already outdated technology.

Feel The Lurve....feel the low bit rate.

[An_Inspector_Calls]

It works now. My word, the web-site administrator might even be watching these pages . . .

Powerful stuff, too!

[Andrew Slater]

I hesitate to post here, but here goes:

First, a bit of history:

Generically, DAB is capable of providing high quality audio, provided that a suitable encoding technique and a sufficiently high bit rate are used in combination. Unfortunately the present offering is, at best, subjectively no better than the VHF/FM alternative, and at worst marginally subjectively worse. This is in great contrast to the obvious advantages offered by VHF/FM over MW/AM (particularly for the Third Programme) when it was introduced in the 1950s: a huge increase in bandwidth from 4.5kHz to 15kHz, no fading or co-channel interference at night, and (later) stereo. In fact, many people went to great lengths to build their own receivers and aerials to receive the new service. That there is no similar rush to build DAB sets today (or write decoding software: there are many sources of amateur software on the web for digital TV, but none for DAB) speaks volumes. Note that, despite the obvious advantages of VHF/FM, the interval between the introduction of VHF and the switching-off of the MW Radio 3 transmitter was over 35 years! Don't worry: I suspect that VHF/FM will be here for at least the next 20 years, despite all the hyperbole.

Because the perceived advantage of DAB over VHF/FM is so slight (if any), the BBC chose to promote it by expanding the services available, which backfired slightly, as the quality of the existing services was reduced, as their bit-rates had to be cut to make way for the new services. I strongly suspect that the (failed) attempts to abolish BBC6 and the Asian Network were at least partly an attempt to relieve the pressure on the BBC's DAB multiplex.

And now, a proposal:

I think that our energies might be better expended in encouraging the BBC to introduce a second national DAB multiplex, to carry 'HD' channels, using for example aac encoding at appropriate bit-rates, with Radio 3, of course, being allocated as high a rate as possible. (There is a precedent for this: digital TV currently carries an HD version of BBC1 (soon to be joined by BBC2) on a separate multiplex from the one used to carry the standard definition version.) All new DAB transmitters should carry this new multiplex, but not the current one, to give a clear message to the set manufacturers. The manufacturers should also be encouraged (forced?) to introduce a user-adjustable variable delay so that all sets within a household may be synchronised. In, say, ten years' time, the old multiplex could be switched off or used for the next generation of DAB transmission technology. (I suspect that it won't stand still.)

That's all I have to say, really.

[Resurrection Man]

Interesting points, Andrew, and you are always very welcome to post.

Regarding your proposal, I'm not convinced of the benefit per se. Surely a better bit-rate etc is only going to be of interest to a relatively small number of listeners...those who are listening in a static environment? I can't conceive that anyone would hear the difference on a kitchen table radio of the increased bit rate ( a fact that Jack Scofield picked up on in his article for the Guardian in response to the Ofcom questionnaire they sent out asking people to tell the difference or if they preferred the sound of DAB vs FM...)..it's in Myth 1 on that website.

So assuming that my assumption is correct then aren't these people already served with excellent bit rates such as the Radio 3HD feed?

[mangerton]

So assuming that my assumption is correct then aren't these people already served with excellent bit rates such as the Radio 3HD feed?

I've been following this thread with great interest. I see both DAB and the downgrading of the VHF/FM service as retrograde steps, driven by money and with no thought of the consequences to the great listening public.

There may well be excellent bit rates on the Radio 3 HD feed, and I am fortunate, as I live in a city, to have a cable connection fast enough to allow me to benefit from this.

However..........I have no great desire to listen to this HD feed on small computer speakers or earphones while sitting on a relatively uncomfortable chair when I have an excellent hifi system and a comfortable armchair. If someone can tell me how to combine the feed and my hifi I should be delighted. I can of course listen to radio from my TV cable box, but the bit rate is not as good as the HD feed.

[Nick_G]

I hesitate to post here, but here goes:

First, a bit of history:

Generically, DAB is capable of providing high quality audio, provided that a suitable encoding technique and a sufficiently high bit rate are used in combination. Unfortunately the present offering is, at best, subjectively no better than the VHF/FM alternative, and at worst marginally subjectively worse. This is in great contrast to the obvious advantages offered by VHF/FM over MW/AM (particularly for the Third Programme) when it was introduced in the 1950s: a huge increase in bandwidth from 4.5kHz to 15kHz, no fading or co-channel interference at night, and (later) stereo. In fact, many people went to great lengths to build their own receivers and aerials to receive the new service. That there is no similar rush to build DAB sets today (or write decoding software: there are many sources of amateur software on the web for digital TV, but none for DAB) speaks volumes. Note that, despite the obvious advantages of VHF/FM, the interval between the introduction of VHF and the switching-off of the MW Radio 3 transmitter was over 35 years! Don't worry: I suspect that VHF/FM will be here for at least the next 20 years, despite all the hyperbole.

Because the perceived advantage of DAB over VHF/FM is so slight (if any), the BBC chose to promote it by expanding the services available, which backfired slightly, as the quality of the existing services was reduced, as their bit-rates had to be cut to make way for the new services. I strongly suspect that the (failed) attempts to abolish BBC6 and the Asian Network were at least partly an attempt to relieve the pressure on the BBC's DAB multiplex.

And now, a proposal:

I think that our energies might be better expended in encouraging the BBC to introduce a second national DAB multiplex, to carry 'HD' channels, using for example aac encoding at appropriate bit-rates, with Radio 3, of course, being allocated as high a rate as possible. (There is a precedent for this: digital TV currently carries an HD version of BBC1 (soon to be joined by BBC2) on a separate multiplex from the one used to carry the standard definition version.) All new DAB transmitters should carry this new multiplex, but not the current one, to give a clear message to the set manufacturers. The manufacturers should also be encouraged (forced?) to introduce a user-adjustable variable delay so that all sets within a household may be synchronised. In, say, ten years' time, the old multiplex could be switched off or used for the next generation of DAB transmission technology. (I suspect that it won't stand still.)

That's all I have to say, really.

Some very interesting points Andrew, and your suggestion is an excellent one - in theory. However, I don't think the funds are there to do this, after the long recession and wasting of money on other things, such as promoting DAB! They even claim that the funds aren't there to continue maintaining the FM transmission network, although I suspect that some of this is that they don't want to. Certainly for commercial radio, the money going into dual transmission can't last for ever, and, judging from the amount of negative comments posted by the public on DAB news articles, I suspect it will all blow up in the industry's face sooner or later.

As for hearing the HD internet feed via your hi-fi, as long as you have an internet set that can hook up to your amp, then you can listen that way.

Regards,
Nick

[Resurrection Man]

I've been following this thread with great interest. I see both DAB and the downgrading of the VHF/FM service as retrograde steps, driven by money and with no thought of the consequences to the great listening public.

There may well be excellent bit rates on the Radio 3 HD feed, and I am fortunate, as I live in a city, to have a cable connection fast enough to allow me to benefit from this.

However..........I have no great desire to listen to this HD feed on small computer speakers or earphones while sitting on a relatively uncomfortable chair when I have an excellent hifi system and a comfortable armchair. If someone can tell me how to combine the feed and my hifi I should be delighted. I can of course listen to radio from my TV cable box, but the bit rate is not as good as the HD feed.

Mangerton...welcome to the thread. There are many ways to achieve what you are after. The most basic way is ..... cable modem/router -> computer -> USB/DAC -> your hi-fi system. You probably have the first two ! The USB/DAC is a box that takes in the digital feed from a USB port on your computer and converts it into audio that you then plug into your hi-fi system.

The next question is how close is your computer to your hi-fi system. If it is a long way away then it gets more complicated but I'm sure that someone will be along to help you in that direction!

Other ways are using more dedicated systems such as the Logitech Touch...but I am not an expert nor familiar with these sorts of things.

[Andrew Slater]

So assuming that my assumption is correct then aren't these people already served with excellent bit rates such as the Radio 3HD feed?

Internet feeds are extremely wasteful of bandwidth when compared with radio broadcasting: the data has to be sent individually to every listener: horses for courses. Furthermore, it's very expensive - I calculated a while ago that I would use up my monthly data allowance in less than 70 hours listening to Radio 3 in that way.

Some very interesting points Andrew, and your suggestion is an excellent one - in theory. However, I don't think the funds are there to do this, after the long recession and wasting of money on other things, such as promoting DAB! They even claim that the funds aren't there to continue maintaining the FM transmission network, although I suspect that some of this is that they don't want to.

Well, money isn't my concern - it's their problem (it can always be found where necessary), and they'll have to do something along the lines I suggest if they are to succeed.

[An_Inspector_Calls]

I think that our energies might be better expended in encouraging the BBC to introduce a second national DAB multiplex, to carry 'HD' channels, using for example aac encoding at appropriate bit-rates, with Radio 3, of course, being allocated as high a rate as possible.

I fully agree that the campaign should aim for a more positive outcome such as improvement in the audio quality of DAB rather than a NIMBY-like fixation on keeping FM. I've advocated that several times on this board. An alternative, or perhaps a parallel, initiative would be increased bit rates on the Freeview and (more easily because of the space availability) Freesat broadcasts

[Bryn]

I fully agree that the campaign should aim for a more positive outcome such as improvement in the audio quality of DAB rather than a NIMBY-like fixation on keeping FM. I've advocated that several times on this board. An alternative, or perhaps a parallel, initiative would be increased bit rates on the Freeview and (more easily because of the space availability) Freesat broadcasts

Not much use for portable listening, however, and pocket DAB devices still, despite improvements in energy management, remains very heavy on batteries compared to FM.

[Resurrection Man]

Not much use for portable listening, however, and pocket DAB devices still, despite improvements in energy management, remains very heavy on batteries compared to FM.

Not to mention many households having several radios which would have to be replaced.

[teamsaint]

I fully agree that the campaign should aim for a more positive outcome such as improvement in the audio quality of DAB rather than a NIMBY-like fixation on keeping FM. I've advocated that several times on this board. An alternative, or perhaps a parallel, initiative would be increased bit rates on the Freeview and (more easily because of the space availability) Freesat broadcasts

Its not really nimby like if, for example, you have just bought one of the very many cars on the market (75%) that only have FM.
Just reasonable.
Or if you live in an area with poor DAB reception. And so on.


FM MAY have had its day, but we pay for it, and are entitled to be listened to , by the "experts".

[Eine Alpensinfonie]

NIMBY, eh? Rather a misunderstanding of the acronym, I'd say.

[JFLL]

Its not really nimby like if, for example, ... you live in an area with poor DAB reception.

Quite. Or indeed, no reception at all:

“DAB coverage is not currently available in your area” (http://www.ukdigitalradio.com/coverage/postcodesearch/)

The area in question is in England, 42 miles from Birmingham, so we're not talking about Outer Mongolia. Can you imagine a place, say, 42 miles from Frankfurt having no reception from a service to be foisted willy-nilly on everyone in Germany?

[An_Inspector_Calls]

NIMBY, eh? Rather a misunderstanding of the acronym, I'd say.

"NIMBY-like" dear, not the same thing at all.

Bryn: Myth 11 then. Funny you can now get DAB radios running on AAA cells

Teamsaint: Or poor FM reception for that matter.