Ideally what we like to see is a transmission
system that is universal in the same way that AM and FM are
all round the world at the moment but that also used spectrum
efficiently, provided excellent technical quality and was
allied with excellent content.
The problem we see is that there are so many conflicts, driven
by a combination of differing interests that this is unlikely
to come about in technical terms and we're not that impressed
with the content likely to be offered in many places.
We still think the idea of using additional spectrum, as is
done with DAB, beats the idea of cramming digital into existing
analogue signals for a number of reasons albeit we are conscious
that the UK DAB transmissions use the inferior (in terms of
getting quality for the same bandwidth) MP2 coding rather
than more advanced codecs that have been developed and are
being used in other systems.
The DAB system can of course adapt to the more advanced coding
- it has to when it is used for DMB (Digital Multimedia Broadcasts)
- and both the Digital Radio Mondiale (DRM) and iBiquity HD
systems use more advanced codecs for their terrestrial transmissions
as do the two satellite services. The problem is that you
can't get all the signals on one receiver albeit combined
DAB/DRM receivers are beginning to be developed and this raised
the question of whether this could be made possible in future
and if so how best to approach future developments.
At the moment as happened with original video recording systems,
consumers are stuck with having to wait or buy equipment that
will almost certainly be inferior - and more costly - to what
is going to be possible and there is no clear inter-compatible
In the US, we believe the Federal Communications Commission
has double-ducked the issue - allowing the satellite companies
to supply proprietary receivers that are good for only one
service and also in taking a route with HD that protects existing
companies at the expense of potential new entrants albeit
the development of broadband - and specifically broadband
wireless - services or of new forms of software-defined systems
could provide workable and economically viable options for
such new entrants.
If they do, our view is that the result will be a more significant
weakening of terrestrial radio than would have happened had
a different approach been adopted using additional spectrum.
Looking at the digital future, we now split our consideration
into areas of technical and content issues.
The whole point going digital relies
on a combination of audio and spectrum use benefits and these
in our view should be indissolubly linked with a consideration
of universality and receiver costs: If the audio is not up
to standard, we can't really see justification for the move
and unless it is significantly better a move can only be justified
in terms of using spectrum more efficiently since, other things
being equal, there is a benefit if audio is the same in being
able to provide more services.
So how does digital fare in these terms. We've already made
our point about universality - something that would also reduce
unit costs as mass manufacture got under way. What about audio
quality and efficient use of spectrum?
This splits into two main elements, the quality as perceived
by a listener and the robustness of the transmission-reception
combination. On the latter we can only speak from our experience
which is effectively limited to Eureka DAB as broadcast in
the UK since to test such things one needs to both have a
variety of similar chosen listening environments, similar
material, and the ability to test in the home, on the move
and in various locations.
That being so we can only comment in terms of the general
qualities of digital namely that the signal remains clear
in terms of interference until nearly our of range when there
is some degradation - one UK comment describes it as like
putting the speakers in "Bubbling mud" - and then
suddenly no signal. That was something we observed dramatically
displayed during a BBC digital audio demonstration (not DAB)
some years ago in the early days of digital when a signal
put down around 301 metres of cable was perfect, at around
301.5 started experiencing problems and at 302 died completely
(We also recall that using only a short length of the wrong
cable destroyed the signal that had been carried successfully
over the 301 metres of properly chosen cable).
In other words for listeners in an area where the signal is
strong, digital audio broadcasts are certainly "cleaner"
than analogue signals unless a high-end properly set up tuner
is being used for the analogue reception.
Of quality as perceived by the listener, we see nothing but
benefit in all the digital systems in use when it comes to
speech and for music the problems are generally a matter of
how good a signal the broadcaster chooses to transmit - broadly
speaking in MP2 (the codec used by the UK DAB system - it
is inferior to MP3 and those used in HD, DRM and DMB) we have
found BBC Radio 3 fine, albeit not CD quality, at 192KBPS,
the normal transmission quality, but not not quite as good
when listened to on quality speakers when, because of sports
broadcasts on Radio Five Live Extra, this is reduced to 160KBPS.
We would note here that a lot depends upon an individual's
hearing - ours is now not as good as it was (a degradation
probably less than that which will be experienced in a few
years by any youngster who overdoes the headphone levels on
a personal audio player), the listening environment and the
quality of the audio equipment and we doubt that we'd notice
the differences had we been listening on standard computer
speakers or in a noisy environment).
For those who want to check in further detail on the comparisons
between analogue and digital and various systems we'd suggest
the following sites:
1 - Sam
C Lin's site for comparisons of CD quality and that
of MP3 - he provides diagrams of analysis of audio from CD
and in MP3 up to 320 KBPS and concludes in essence that, even
with excellent hearing (up to 20KHZ in his case - and we'd
add that lower bit rates cut the higher frequencies), 192Kbps
MP3 is more than adequate for listening with a computer or
in a car and 256Kbps and 320Kbps MP3 were virtually indistinguishable
from the CD. He added that non-critical listeners really don't
notice (nor do they care about) the difference in audio quality
between CD's and 128Kbps MP3's.
Green's site - A UK site that compares various digital
audio standards, severely criticises current UK DAB standards
and also provides some very useful comparative samples.
They are in the MP2 format UK that DAB transmissions use (which
you can play on a computer or save as MP3 and burn to CD)
plus some BBC comparisons from FM (in MP3 format), Classic
FM in MP2 and from FM (in AAC/MPEG-4 format) , and also some
BBC Radio 3 classical music samples from FM as AAC (MPEG4
- this will play in Real Player or WinAmp but you will have
to download the 3ivx MPEG-4 toolkit to play this in WMP),
MP3 (320KBPS) and lossless FLAC format (with a link to download
FLAC and WinAmp - the 15.7 MB FLAC file, by the way, became
7.2 MB when converted to 320kbps MP3).
comparison samples -these are 160 KBPS MP3 promos rather than
real samples, meant to show the improvement HD brings, disappointing
in their choice and variety and also quality. If these are
the best it can do it's a system best scrapped unless it has
tremendous other advantages. In addition if it's a real demonstration
of the quality of some US analogue transmissions (listen to
the FM Jazz samples - there is no classical music sample from
FM, only from AM - then compare to Green's FM samples of BBC
Radio 3) it scores to a considerable degree because US analogue
radio is so poor.
Technologies site for information on various codecs.
We regret we have been unable to find any reasonable comparisons
between XM's standards (it uses CT-aacPlus encoding)
and those of Sirius (it uses PAC- Perceptual
Audio Coder and the latest information we have been able to
find on Lucent's site simply says this delivers "CD-like
quality audio at 96 Kilobits per second") nor a reasonable
assessment of their quality compared to CD, DAB and HD. Because
they are proprietary systems, details do not seem to be public
and we have found no sites offering audio samples.
Efficient Use of Spectrum:
This is an area where time has brought considerable improvements
in codecs that allow the same quality to be achieved at lower
bit rates - see the links above for more - and should the
broadcasters wish to provide the technical quality would certainly
enable audio to be transmitted at CD quality as opposed to
near-CD (The latter term an exaggeration for HD if the samples
they provide are anything to go by).
The best technical quality in will never
make interesting audio of someone who can't sing singing caterwauling,
can't use a bow scraping a violin, or with nothing to say
droning on in a monotone and we remember nearly 20 years ago
now being involved in a discussion on what would fill a 750
or 1,000 channel TV world. At that time our views were that,
like specialist magazine publishing that was beginning to
take off thanks to the development of desktop publishing technology,
the only way in which that number of channels could be filled
- we were thinking in terms of one-language area - would be
with a combination of a fairly small number of mass audience
services plus specialist channels, some of which would be
pay channels. Had we been asked the same about radio, our
response would have been the same.
We have seen little to change this perspective since except
that the internet has changed the nature of advertising to
a degree that in our view exacerbates the problems for mass
audience services and also allowed on-demand services that
can considerably expand the range of pay services, something
that is also being boosted by mobile technologies.
The mass audience services - on radio or TV - will therefore
in our view find it increasingly difficult to fund themselves
from advertising as agencies move to more targeted approaches
but will always fulfil some advertising needs but specialist
and pay services will grow in comparison.
So in practical terms what does this mean for digital radio?
Where it is advertising-funded, we see online continuing to
make inroads into local advertising but additional services
could tap some of the revenues that would otherwise have been
lost as indeed can web sites. The net effect in our view will
however not be as positive as some of the promotional material
for HD in the US suggests.
When it comes to music, other forms of listening will continue
to take some of the share (and when it comes to pop it would
seem that the video is considered essential -- it doesn't
seem to be irrelevant to sales in the classical world either
as Vanessa Mae's wet clothing would indicate) but there will
still be a demand for a simple and cheap way to sample new
songs. HD channels will help this albeit satellite radio is
always going to provide more in this area and we suspect that
in the long run a large percentage of those who have tried
satellite will stick with it.
For news or programming that has a news content, however,
downloads and podcasts will always be behind radio so we suspect
that these formats are likely to retain their strength albeit
not expand that much using additional channels.
For public broadcasters and indeed for material on commercial
channels that sponsors want to be associated with we think
digital will enable expansion and potential additional use
of archived comedy and drama and documentary services. We
could also at one time have seen broadcast as a way round
some of the limitations of online but as broadband proliferates
this may be less of a benefit albeit the internet is still
a less efficient way of distributing on a one-to-many basis.
Overall therefore we think extra digital channels will be
good for radio as they allow additional services but that
this is only up to a point since listening time won't expand
that much and the extra services all involve some cost, however
small. We certainly wouldn't be tempted to increase valuations
of radio stocks that significantly on the back of digital.
Overall we think digital can be of considerable
benefit but are concerned about two major issues - that of
broadcasters trying to cram too much into available spectrum
with consequent technical quality degradation and of the loss
of a worldwide universal standard that currently benefits
analogue consumers because it has brought the cost of transmitters
and receivers down to a very low level and allowed equipment
to be used round the world.
We know technology will continue to advance but within limits
as far as compression technologies go - once you've got most
of the compression right there's a limit to how much further
reductions in requirements can be achieved.
What we'd like to see therefore is planning ahead and international
agreement on standards for a DAB-based system
using the best codec available; on an open-standard for encoding
digital within existing signals - DRM is already
open, of course, and we'd like to see HD presented with the
option of competing to win an open-standard contest or killed
off but admit we may be biased by
the fact that on the samples it provides, it's best is considerably
inferior to the FM sample on Steven Green's site
- and surely iBiquity SHOULD be showing off the best it can
do!; and on a universal standard for satellite audio (currently
represented by WorldSpace, Sirius,
XM and audio channels on digital TV platforms).
Such agreement ideally should be reached within 3-4 years
with the aim of putting all systems worldwide on the same
standards say ten years hence, with agreement also on spectrum
use to allow a gradual move to the new platforms in the meantime
until the old digital systems are switched off.
As far as equipment is concerned, we'd like to see the development
of chip technology that would allow receivers sold to be upgraded
to new standards - either by software upgrades or chips that
be changed simply by a user.
Such a system would we think be to the overall benefit of
listeners and manufacturers, would bring the cost of receivers
down dramatically, and be of tremendous advantage in maintaining
open broadcast standards for travellers and international
broadcasts (think how much some governments would love to
have a proprietary system that prevents people being able
to receive information from outside.).
We see some problems with this scenario - iBiquity and existing
US radio players who benefit from the current proprietary
systems would fight tooth and nail to keep their dominance
and exclude other players from the market - but they're problems
of the few not the many.
Perhaps the best compromise in the US would be to introduce
a new open system (such as DRM if iBiquity isn't prepared
to move and can't win the contest on technical grounds) for
encoding in current signals and require broadcasters to use
it as a condition of licence (Yes, it would mean fewer HD
signals in the meantime) and a universal system for satellite
transmissions and require XM, Sirius and other players to
use that) thus giving US listeners the benefits of reduced
receiver prices from a worldwide market and allowing the proprietary
signals to lapse into disuse.