The quality and the width 

15 August 2001

EDITOR’S NOTE: This article is more than 20 years old. The formatting may be strange, links broken and/or images missing. The text may have been superseded by subsequent events or later research.

In the beginning Marconi created AM.

Of course, sound quality wasn’t an issue at first; it was miracle enough that stuff could be transmitted across great distances at all and radio soon began to change our lives.

Reception, using primitive crystal sets was a cranky and, at first, solitary experience, and whilst wireless sets soon improved ‘hi-fi’ quality was an unknown concept until the late 1940s / early 1950s.

It was the gramophone recording industry that led the way, and the invention of the microgroove record was a revelation which spurred hi-fi enthusiasts on, but as far as radio was concerned the AM system was incapable of improvement. For radio quality to improve to the point where the sound quality would not only match but also improve upon the current state-of-the-art, radio stations would have to occupy double or triple the bandwidth and that space could not be found without causing interference to other broadcasters. Clearly a new system was needed, and FM – frequency modulation was developed to fulfill the requirement.

The new system still needed more bandwidth to operate successfully but that could be found by transmitting the brand new system on a brand new waveband, beyond Short Wave and higher even than the frequencies then used for BBC Television, it was VHF – Very High Frequency.

So, on 2-May-1955 the BBC opened its first ever VHF radio service broadcasting the Light Programme, Third Programme and Home Service to London and parts of SE England from a site to the SE of London at Wrotham in Kent. This was the start of a plan to provide VHF radio to virtually all the UK’s population and the network of transmitters grew steadily during the following 5 years.

On 28-Aug-1962 the BBC began making stereo test transmissions using the Third Programme transmitter at Wrotham using the Zenith/General Electric multiplex system, the very one still in use for FM stereo today.

This transmitter remained the only source of stereo radio for some years. The problem for the BBC was not so much the transmission of stereo per se, but the distribution of stereo to its transmitters. At that time the BBC had to rely entirely on the GPO’s network of landlines for programme distribution and stereo required not one but two such lines. Moreover, these lines had to be carefully matched in terms of their quality and their length, and this presented real difficulty.

Post Office engineers were able to provide not just one but two such pairs of lines between Broadcasting House and the Wrotham transmitter and these were specially equalised to be accurate up to 20kHz (the limit of human hearing), but other transmitters were linked by single, mono lines guaranteed to have a ‘flat’ response to just 12kHz. The keen-eared radio enthusiast could tune around various neighbouring VHF stations during the 60s and hear each transmitter putting out a slightly different sounding version of each station, all of them poor by today’s standards.

By 1971 stereo Radio 3 (as it was now called, of course) had been gradually extended to around 60pc of the UK population from just six main stations and six low-power relays. Signal distribution was to allow this was achieved by a combination of off-air receivers and micro-wave links, but Radios 2 & 4 were still mono and Radio 1 was still AM only.

By 1973 the BBC had finally cracked the problem of stereo programme distribution. Basically the answer was, in a word, digital. Of course the BBC would never use one word where three would do, so they called it Pulse Code Modulation. The system could wrap 13 audio channels up into one digital bitstream, which could then be carried easily using the sort of link used to carry a television picture. This meant the PCM could carry four stereo radio stations and still have some capacity left over. The big advantages of the system were that quality was guaranteed, regardless of the length of the link, and as all the channels were bundled together they each took the same route and were perfectly matched.

So it was that in 1973 the BBC added stereo capability to Radios 2 & 4. The event was marked by a ‘stereo week’ during which much was made of old, familiar programmes being heard in stereo for the first time, and of new dramas and features. Even R3 joined in and one of their highlights that week was a rare programme made by the BBC Radiophonic Workshop called ‘The Space Between’.

And so, BBC stereo radio finally began to extend across the British Isles.

On 5-Jul-1974 the BBC took the unusual step of broadcasting a quadrasonic (4-channel) programme using Radio 4 to carry the two front channels and Radio 3 to carry the two rear channels. Listeners were encouraged to gather two stereo radio systems together to listen to the broadcast, or, failing that, a mono radio could be tuned to R3 for a single rear channel. The broadcast, which went out at midnight, consisted of short selections of specially recorded music and drama.

This begs the question of whether or not there has ever been any other surround sound broadcasting in the UK, and the answer is yes, there has. At around this time the BBC also began looking at the ‘matrix’ encoding systems which attempted to encode information for 4 speakers into the two available stereo channels and the BBC made a number of broadcasts using a system they called Matrix H, which was a very slightly modified version of Sansui’s QS system. Very few Matrix H decoders were in use but despite that almost an entire season of Promenade Concerts was broadcast in this way.

There were the ‘binaural stereo’ programmes made using ‘dummy head’ microphones which could give a very convincing sense of spatial awareness if the programme was heard through a high quality pair of headphones, and more recently some programmes have been made in Dolby Surround, but these are rare and hardly ever publicised.

Meanwhile, back in the mid-70s, Radio 1 was still on AM only. At least it was for most of the time.

The R2 VHF stereo network was shared with R1 and the pop station got to play with it for two hours a night, between 2200-0000, on Saturday afternoons until 1930 and Sunday evenings from 1700.

This network splitting was clearly an uneasy compromise, with which neither network was happy, and as Independent Local Radio spread around the country offering pop music in FM stereo, Radio 1 was beginning to look like something of a dinosaur, technically speaking. In 1978 it was moved from the troublesome 247m wavelength to 275/285m (1089/1053kHz) which greatly improved reception at night but this was still AM and still mono.

The problem with the VHF/FM band was that about half of it had traditionally been used by the public services (police, the ambulance service etc.) and the Department of Trade and Industry, who had inherited responsibility for the airwaves from the defunct Ministry of Posts and Telecommunications, took an incredibly long time to clear the remainder of the band for broadcast use. They had begun by clearing frequencies for ILR to begin in 1973 but the process cost money and clearing more space to accommodate BBC Radio 1 would raise no additional revenue. But eventually the process was started and the BBC at last opened the first FM transmitter for Radio 1 in October 1987.

This was actually quite poignant moment. The transmitter was quite a low-power one – just covering London from Crystal Palace on 104.8MHz – and no on-air mention was made by the station at all, other than the hint offered by their first song played at 6am: “FM” by Steely Dan.

The Radio 1 FM network gradually rolled out to the rest of the country of the next three years or so, first between 98-99FM and ultimately between 97.7-99.9.

Sadly, and ironically, this period was also seeing a rapid decline in the quality of FM broadcasting. It may seem paradoxical, but it always seems that the appearance on the scene of competition ultimately ends in standards falling under the domination of the lowest common denominator: money.

The new breed of BBC and ILR stations were entirely self-operated – in other words responsibility for the quality of the station’s output devolved from a dedicated engineer to the presenter, and sound quality is often the last thing on a presenter’s mind. Usually he will have a number of other things to worry about including their guests, their music and their timekeeping. They are also unlikely to be in a position to make objective judgements about how they and their programme sound. But doing away with an engineer and a main control room was a considerable saving and most listeners didn’t notice the difference, so that was that.

Another nail in the radio engineer’s coffin was the introduction of the automatic dynamics processor. These things are usually referred to as Optimod, in much the same way as vacuum cleaners are referred to as Hoovers. Some might argue that there is another similarity too: they both suck.

It has to be said that if you are going to operate a radio station with staff who are inexperienced, untrained and as few in number as possible then you had better do it with something like an Optimod controlling the output, otherwise the station will sound dreadful. With dynamics processing, however, your station can sound LOUD. ALL THE TIME. MUCH LOUDER THAN THE COMPETITION. EXCEPT, OF COURSE, THAT THEY’VE GOT A PROCESSOR AS WELL, SO NOW EVERYTHING SOUNDS LOUD EVERYWHERE. ALL THE TIME. AND IT GETS VERY TIRING TO LISTEN TO AFTER A WHILE. I THINK YOU GET THE IDEA.

In case you’re in any doubt, pretty well all BBC and ILR stations now use this type of processing on both their FM and AM transmitters. It can work reasonably well and it certainly helps with audibility and intelligibility if you happen to be listening to the radio in a noisy environment, but it is hardly progress in quality terms and has pretty much written off FM as a high quality, hi-fi audio source.

And so, finally, to the latest radio development: Digital Radio.

Again, why use two words when three would do…? At first it was called Digital Audio Broadcasting (DAB) but the BBC are now encouraging us to call it simply Digital Radio.

Digital Radio is to FM pretty much what the CD was to the LP. No more crackles, hiss or interference, just pure sound. Except that hardly anyone seems to be interested. One of the reasons could be that when the system was first launched there were only a handful of receivers available and these were all car radios and very expensive ones at that. In due course Arcam brought out a DAB tuner for home hi-fi enthusiasts but this was also expensive at around £700. Too much for most people, most of whom just want a nice, cheap little radio that they can carry from room to room and which will preferably work without having to extend and fiddle with a telescopic aerial.

There is no doubt that digital radio is sonically the best yet, but it’s taking a long time to catch on. Perhaps if Trevor Bayliss were to make a wind-up digital radio..?

You Say

5 responses to this article

Christopher Langley 11 August 2013 at 10:08 am

DAB Radio sound quality as transmitted in the UK is appalling.

There have been a very large number of complaints to the BBC on the poor high frequency response of DAB radio which makes music sound dull.

The BBC should be ashamed of themselves for both trying to muddy the water between DAB radio and digital audio which in itself has no technical relationship with CD audio quality, and selling to the general public and Parliament obsolete technology.

Your statement on digital radio spoils what is otherwise an interesting and accurate synopsis of how free from Engineers, “Never mind the quality, feel the width” is now the mantra of radio.

Geoffrey Kolbe 6 January 2014 at 7:17 pm

The word “Internet” did not appear in the article once. But that is where the future of radio is. DAB radio is Dead And Buried, the men and the Ministry just don’t realise it.

As for processed sound, the BBC (Radio 3 anyway) is by no means the worst sinner. Classic FM is so “processed” it has no dynamic range at all. But that is true for most CD offerings as well – to the point where we start to think that is how is should sound.

But… I am sure there will be a swing back. Just as people are interested in hearing period music on period instruments, so people will always be interested in recordings created to sound like the real thing.

Philip 18 August 2014 at 8:08 pm

@Geoffrey If you looked at the date this article was published you might see why internet radio was not talked about.

Peter Hutchinson 15 January 2017 at 12:02 pm

I was involved in listening tests for digital radio in the 1990s. The quality of the source was compared to compressed digital. The result was acceptable for speech based radio, and to some extent on music content that had been heavily compressed in the recording phase. However, on classical music, the result was to my ears unacceptable. Nearly all the depth and ambience between instruments was lacking, and the end result was flat, compressed and lifeless. The correct application for DAB is the portable radio, where none of this matters much, as a portable isn’t capable of reproducing detail anyway. In an age where music downloads are MP3, and all radio stations use Optimod, it would seem that there are few people around now who care much about quality sound. However, if you are one of those people, then DON’T buy a DAB tuner. It will sound worse than your existing FM tuner, if you mainly listen to classical music through a half decent HI-FI system.
Norway is the first country to close it’s analogue FM stations in favour of digital only radio. I hope it doesn’t happen here in the UK for decades, or at least until a means is found to transmit full quality, uncompressed CD quality sound. Given the frequencies in use for DAB, one would hope that multiplex bandwidth could be increased to permit better quality by using much less digital compression.

Michael O'Beirne 29 July 2020 at 1:13 pm

It’s instructive to compare BBC Radio 3 carefully and critically on FM and DAB using good quality Sony headphones. Quite apart from the 3 second delay (caused by the added processing required by DAB), there is no doubting the superiority of FM. DAB has a nasty metallic twang to it, particularly noticeable on speech.

DAB should be binned ASAP or swapped for a much better digital modulation system. God help us if FM is abolished and the frequency band flogged off to some commercial user.

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