The Killer App for FM:
5.1 Surround Sound
by Frank Foti, Omnia Audio
February, 2005
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ABSTRACT
For the past few decades, the appeal of FM radio has been its technical
superiority: Low noise and stereo sound. (Remember Steely Dan’s “FM…No static at
all!”) The world has moved on and FM as a technical medium has become status
quo. Multichannel sound
exists for television, personal computers, video games, and DVD – both video and
audio. Now for the first time since 1961, when FM implemented stereo, we have
technology that will keep FM radio competitive with other existing mediums. The
ability to broadcast
distinct 5.1 multichannel audio.
ANYONE FOR PIZZA
When was the last time you turned on the radio and heard something truly
exciting? Think about it. Take a moment and really think about it…Not easy is
it? For me, it’s probably during the last hey day of CHR, about 20 years ago,
when Z-100 (WHTZ) made its run in
New York City.
Now, look at radio today. It's losing market share to so many alternatives:
mobile CD listening, iPod, XM/Sirius, and netcasting. While none of those
entities alone are defeating radio, combined they are eroding the listener base.
Recently, at the Radio & Records Convention in Los Angeles the following dialog
occurred with a well-known corporate Program Director who did not want to admit
that his legacy station was losing audience. His claim was: "Hey, even with XM
and Sirius around I still have a 4.3 share in Los Angeles." The reply to him:
"Yes, you do still have a 4.3 share...BUT...the pie is smaller, and why is
that?" Interesting in that he had no rebuttal.
Pizza analogy: Many people can eat half of an 8 cut pizza easily. If the pizza
is 12 inches round, that's a lot of pizza. If the pizza is 10 inches round, then
it's a smaller pizza, but in both cases they've consumed a 50% share of the
pizza. Think of radio ratings shares the same way. The radio “pizza” is getting
smaller! If terrestrial broadcasters don't respond soon, that same PD who once
had a 4.3 share of a huge LA audience, and now has a 4.3 share of a smaller
audience, will soon have a 4.3 share of next to no audience!
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Fortunately, pessimism has never been my strong suit. I’ve heard the future of
FM Radio, and it’s truly exciting! The amazing thing about this new enthusiasm
is that it’s not a new format, super-duper air talent, or an amazing station
giveaway. Surprisingly, it’s technical…distinct multichannel sound in 5.1
glorious channels!
THE KILLER APP
The multichannel system invented by Fraunhofer Institute (FhG) and Agere Systems
comes from people who know their stuff. FhG are the folks who created MP3 and
MPEG AAC. They are also getting a lot attention for their new Iosono system that
uses as many as 304 loudspeakers to create an amazingly enveloping soundspace
for applications like high-end movie theaters. The Agere people are former
Lucent and Bell Labs audio coding researchers. Sparing all the technobabble,
this surround system will provide a distinct
multichannel listening experience to the FM radio audience. This is accomplished
using a technique called coded-discrete which prepares the audio for
transmission over iBiquity’s HD Radio® system.
The Fraunhofer Institute (FhG) folks have been busy pushing the frontiers of
perceptual audio research. The latest result is a powerful spatial audio coding
system that takes advantage of the most up-to-date knowledge in aural
perception. From psychoacoustics studies, it has been learned that the level
difference, time difference, and coherence between channels is what creates the
perception of spatial image. The key to FhG’s multichannel system is that they
represent these difference values with very compact coding, rather than
transmitting all of the individual audio channels. The encoder estimates the
values as a function of frequency (that is, within each sub-band) and transmits
them to the decoder in an ancillary stream that accompanies the main coded audio
stream.
The enclosed block diagrams illustrate how an encoder/decoder pair would work
within a broadcast channel such as HD Radio®. Following are descriptions of two
implementations.
Compatible Down-Mix
The first step is to create a compatible stereo downmix from the multichannel
material. The resulting stereo signal is coded using any perceptual codec. Since
there are no changes to the basic codec, this signal can be received by stereo
radios. The spatial encoder extracts the various spatial cue parameters from the
multichannel input, which are transmitted in an ancillary data channel. The
decoder, if present in the receiver, recreates the original multichannel audio.
In the diagrams, you can see that we need to have a downmix function to create
the compatible stereo channels from the multichannel source. The most obvious
way to do this is with simple linear combiner, as follows:
L = Lfront + a*Lrear + b*Center
R = Rfront + a*Rrear + b*Center
Where a and b are constant scale factors, with the values usually ranging from
.5 to .7. But this simple procedure, Figure-1, is far from the best possible.
When making an optimized downmix, a number of considerations come into play,
which comes from both psychoacoustics and production practices. We must present
a stereo mix to listeners without multichannel receivers that is as good as a
stereo-only broadcast. Simply collapsing the front and back signals into a 2-
channel representation may cause some confusion in
the normal binaural cues and degrade stereo listening. And it almost certainly
will sound different from the version that listeners are used to. The FhG system
allows a producer to make a manual downmix, thus preserving maximum artistic
freedom and allowing
maximum flexibility to adapt to different kinds of audio material. Since almost
all music released in surround format also has a stereo version on the same disk
that could be used as input to the encoder, this stereo version is what would be
heard by listeners with nonsurround radios – with no modification or compromise
of any kind.
Advanced automated downmixing is also an option when manual mixes are not
available. A processor could dynamically modify the scaling values and relative
phase during mixdown. Such a processor would use advanced algorithms that can
take into consideration absolute source positioning, panning laws, the way
sources were mixed into the multichannel signals, and original inter-channel
phase relationships, so it would have the potential to achieve quality that is
comparable to manual downmixes.
5.1/ 2.0 Discrete Method
Figure-2 is an example of an optimal method that supports both 5.1 surround and
2.0 stereo mixes. By utilizing the original stereo mix for the transmission
path, and the 5.1 channels for the surround encoder, the best of both are
available. It’s important to note that all of the signals required for surround
replication already exist in the stereo mix. The 5.1 channel data is used to
restore the original placement of the multichannels.
The configuration of this embodiment can exist in two manners. The obvious would
be to employ the wave extensible file format that would include eight (8)
channels of audio (5.1 and 2.0), or the encoded 2.0 stream could adapt the
surround information as metadata and thus create a quasi 2.1 signal.
This encoding method must rely upon the content of both mixes being exactly the
same. If that’s not possible, then the compatible downmix method can be used as
an alternative.
Note: Since the original, or optimized stereo mix is used to support 2.0
listening, it goes without reason that this will also support monaural 100% of
the time.
Receiver Overview
The receiver embodiment is the inverse of the above described functions. A
stereo perceptual decoder will recognize the ancillary side-channel data and
forward that to a surround decoder along with the Left/Right audio. Utilizing
the inverse function of the encoding method, the surround channels are restored
to their original placement and 5.1 audio is presented to the amplier and
speakers. If the receiver does not contain the stereo perceptual decoder, then
the original stereo signal is passed to the output of the receiver.
Figure-3 illustrates the receiver function.
All well and good, but will this work with HD Radio®? The astonishing answer is:
Yes! The FhG spatial encoding system is fully compatible with HD Radio’s®
current codec for the stereo channels. And the sidechannel for spatial
information is less than 20kbps, a
rate that fits well within the HD Radio® ancillary data channel. The system was
demonstrated last fall in San Diego at the NAB Radio Convention.
INFRASTRUCTURE
A topic worth discussion is technical infrastructure. The studio facility will
need to be upgraded to surround. But in this evolving iMedia world, adding
distinct 5.1 audio is not the challenge that FM faced when it rolled out stereo
in 1961.
Here’s a point to ponder: When stereo records were first introduced, the
only available content was whatever was recorded at that time in stereo, as all
older material only existed in monaural. It is much easier with 5.1 audio, as
multi-track master recordings of older material already exist and can be remixed
for surround. Imagine what it would have been like at the inception of stereo,
if there were archived 2-track recordings of the Glenn Miller Orchestra, or
other famous artists from that era.
While at first blush it would be understandable to think that there is a need to
triple the audio channels around a facility with more cabling, switching, and
routing. Actually, adding multichannel audio is as easy as CAT5. Look around,
the world today is migrating to
network based audio distribution via high-speed networks. Adding more channels
to a network based router and cabling installation is done mostly by changing
the software of the system, at very little incremental cost. The same holds true
for delivery systems. Modern consoles use the surface+engine configuration, so
existing surfaces might well be connected to upgraded engines. For more
information on an innovative networkable solution, check out:
www.axiaaudio.com .
Regarding the multipaired cables and AES configuration: Computer networks are
taking over these obsolete technologies - and with an Ethernet networked studio
approach, the incremental costs to move from stereo to discrete surround are
near zero. The majority
of studios on-air today are still analog and need to be upgraded to digital
anyway, so the surround capability comes along for the ride.
Audio Processing
A unique aspect to this transmission method is the ability to employ existing
2.0 style audio processing. Since the main audio path remains in a two channel
format, conventional audio processors can manage all processing requirements.
NOT YOUR DAD’S SURROUND…(MATRIXING)
It must be stated that this coded-discrete system offers distinct surround
sound. With the exception of the implementation from Coding Technologies, the
other designed systems are matrix based or they contain multiple drawbacks that
can compromise and degrade
the 5.1 multichannel audio, as well as the existing stereo and mono mixes.
Consider that the FM-Stereo system in place today offers discrete 2-channel
audio with separation that theoretically approaches 70dB. It’s extremely
doubtful that our industry would have accepted a broadcast system for FM-Stereo
that utilized synthesized 2-channel duophonic sound, and passed that off as
stereo. This is what the other proponents wish to do.
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The matrixed methods synthesize and fake the 5.1 audio
channels. They do this by manipulating the original stereo mix to create
the surround effect. In doing so, this technique also alters the
original stereo mix so that now BOTH the stereo and surround signalsare
in effect spatially distorted. This type of approach is not the answer,
or solution, to boost radio listening forward. Basically these other
systems have renewed those old quad concepts from the 1970’s and
repackaged them as digital in hopes of banking on old
tech.
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Ask Dad about this backwater tech! |
The method described herein is innovative, and it totally preserves spatiality
of BOTH the stereo and 5.1 audio mixes. Radio needs the real thing, not
synthesized, not matrixed, not compromised. For surround on radio to be
respected and to successfully compete with other media, it must be
state-of-the-art performance.
Now it’s worth pointing out a key reason why the matrix systems all contain a
flaw, which spatially distorts the audio. Please understand, the word distort is
used here in a different context than normally associated with audio. It refers
to the loss of spatiality in an audio environment, as compared to the edgy,
rough sound that distortion of a harmonic nature (THD) exhibits.
The area of concern with the matrix systems is the loss of separation in the
spatial-axial patterns between the Left-Front/Right-Rear and the
Right-Front/Left-Rear channels. Audio signals along these two axis will tend to
bleed into one another. Figure-4, offers an illustration.
The arrows correlate to the paths of perceived multichannel artifacts. They are
heard as false spatial cues and lost separation. Maybe you remember the
quadraphonic systems from the 70’s that had a brief and unsuccessful run at a
few radio stations? Don’t confuse this modern multichannel perceptual approach
with those – or any of the current descendents that are around. Matrix methods
have a critical drawback in that only fixed-scale downmixes are possible, so
stereo compatibility suffers. This is one reason the 70’s era matrix systems
didn’t catch on – they had a weird soft and indistinct quality in stereo.
Clearly, this is an important issue for broadcasters. With most people listening
in stereo, we can’t afford to compromise our fundamental service. And that is
why the FhG approach is so well suited to radio broadcast: the system does not
depend upon any specific downmix procedure to work. Indeed, the downmixing
process can be thought of as a component outside of the basic spatial coding
system.
Another problem with matrix schemes is poor surround separation. Matrix systems
must mingle everything into a 2-channel signal, which is a crippling constraint
on performance. They can have only a few dB separation between some of the
channel pairs. (Which channels get the separation and which don’t are design
compromises. Each system deals with this differently.)
Because FhG’s spatial encoding uses an independent digital side-channel and a
modern perceptual approach to spatial cue encoding, it offers very high
separation that is not dependent on the nature of the audio or that needs to be
compromised for stereo compatibility.
By the way, beware of demonstrations using material in one or two channels at a
time. These are deceptive because a steering circuit – a gain processor in
something like a noise-gate configuration combined with an operation that
dynamically varies the matrix coefficients – detects this very directional
condition and steers the strongest signal into the target channel, while
reducing gain or providing some kind of cancellation in the other channels.
(This approach is also a leftover from the 70’s, having first been used in the
Tate and
Vario-Matrix “logic” schemes.) With normal non-pingpong programming, which has
material present in all the channels simultaneously, the separation is dependent
upon the underlying matrix scheme and is much poorer than the demonstrations
suggest.
CODED-DISCRETE VS. WATERMARKING
It must be stated that alternative surround methods which employ
watermarking will not offer much additional benefit than the matrix systems.
Reason being, is that a watermark function can not contain the needed data
payload to properly manage all of the audio
channels over the entire spectrum. There will be aural compromises to this
scheme, especially in separation and placement.
Psychoacoustic research has shown that acceptable surround is created when the
ancillary data payload is set between 10kbps – 20kbps. If the watermarked system
is embedding data payload at this level, the question arises as to how much of
the data payload will
pass through the audio codec used in the HD Radio system. The rate that is
considered robust in the context of anti-piracy watermarking is 5-10 bits per
second. Experts say that around 100 bits per second would be pretty much the
limit in order to withstand passage
through usual codecs. There seems to be a huge disconnect here with regards to
the capabilities of the watermark. If a watermark is only capable of 100 bits
per second, yet surround requires more than 10kbps, something does not add up
correctly!
Watermark Application Concerns
1. Cross-mixing
With a watermarked implementation, what would happen if two pre-coded sources
(stored on a delivery system, for e.g.) were to be cross-mixed on-air? During
the overlap time, wouldn't the watermark become corrupted and the received
multichannels sound quite
strange, or collapse to stereo? Has cross-mixing been demonstrated? How would a
surround or panned mic be added to a mix for voice-overs? Certainly crossmixing
and announcer voice-overs are routine in normal radio programming.
2. Fixed-Downmix To Create Stereo
With a watermarked system, stereo is always derived (downmixed) from the 5.1
multichannels. If this is a satisfactory procedure, why don't DVD-Audio and SACD
disks use the same approach? They could save a lot of bits and trouble by
providing only the surround mix and letting stereo players do a mechanical
downmix. But they never do, instead providing listeners with human-optimized
mixes for each mode.
When a fixed-downmix is employed for stereo, it’s not a guarantee that the mix
levels will result in the same aesthetic texture as a human optimized mix. This
may result in poor sounding stereo, loss of depth or sound stage, and
destruction to the mono sum. This is very
critical as it would lend itself to inconsistent sound for those listening in
stereo or mono.
Thus far the test broadcasts with the watermarked system were with live concerts
that were produced in surround. So, what reference was there to know of "no
surprises in the stereo mix," since there was no stereo original for comparison?
A fair evaluation would be to
test with DVD-A or SACD music as source, so the listener can evaluate carefully
and accurately if the stereo/mono is OK. This is going to be critical to
acceptance of a broadcast surround system since weird sounding stereo is
certainly going to trigger protests from program directors, listeners, and
owners. Figure-5 is an example of a fixed-downmix method.
If you refer back to Figure-1 of this paper, you’ll notice that embodiment
uses a variation of this known as a compatible downmix. Note this
discussion also mentions that this method is not preferable for the surround
encoder. It’s for the same reasons described above that the compatible downmix
is not employed. This alternative method is available when multichannel and
stereo versions of content will not be the same. In that case, the compatible
downmix can be used to create the surround signal.
STANDARDIZING…
The ISO/MPEG audio group has noted the recent advances of surround and its
market potential. They have started a new work item with the working title
Spatial Audio Coding. FhG submitted their spatial approach to MPEG for
consideration and testing, and chances are good that it or some variation will
eventually be approved as an international standard. Thus there will be the
usual advantages of MPEG: an independent confirmation of performance, and
assurance of fair and equal access to licensing. It is the suggestion of
this writer that the NRSC Committee consider an MPEG like study to determine the
performance and preference for a single FM-Surround transmission system.
Speaking of tests, why hasn't the watermarking proponent submitted their tech to
the scrutiny of the unbiased MPEG testing that has been ongoing? At what point
will they offer an honest description of their system so it can be evaluated on
a reasonable basis?
Adopt A Single 5.1 Method
Can you say “AM-Stereo!” The iBiquity Digital Corporation, the creator of the HD
Radio system, needs to adopt a standardized surround transmission system.
Broadcasting can not afford a replay of the AM-Stereo fiasco. The marketplace
decision did not work, and the
technology failed on account of it! When television adopted stereo transmission,
a single system was chosen and that aided in the successful rollout of TVStereo.
As stated earlier, the FhG surround technology is capable of faithfully
reproducing the sound field without degrading both the surround effect and the
conventional stereo and mono signals. Ideally iBiquity would select one single
system, to hasten the acceptance of this exciting tech. There are other proposed
methods out there and iBiquity has been reluctant to endorse a particular system
out of risk in
offending the others, but the fact is that ALL of them offer degrading
performance to both the surround and stereo performance. This writer believes
that iBiquity must get off the fence in order to launch surround on FM with the
best tech possible.
Receiver manufacturers also need to choose a single reception method for their
systems. Once the record labels and broadcasters are on-board, then the receiver
folks will follow. It stands to reason that they will sell more speakers,
amplifiers, and radios…a victory all the
way around for everyone.
The FhG/Agere system will appeal to manufacturers because MPEG standardization
means that the tech will be universally available to all manufacturers at a
reasonable cost. One of the reasons MP3 has grown so fast is that it is an open
standard available to all.
Where The Rubber Meets The Road!
Consideration needs to be given to the following: Should broadcasters adopt a
watermarked system that has had limited on-air testing, little or no disclosure
of technology, no comparative evaluation of performance, a single vendor source,
and troublesome claims?
Or, should they support the MPEG system, described herein, that has been
carefully tested in a controlled
scientific fashion with a wide variety of source audio material. Its developers
include Fraunhofer Laboratory (inventors of MP3 and MPEG AAC), Agere (former
Bell Labs and Lucent researchers), Coding Technologies (inventors of the
"plus" enhancements to MP3 and AAC and the HD Radio codec), and Philips
(co-inventor of MPEG Layer 2 and a leading consumer electronics firm). More
testing is forthcoming as the best ideas continue to be merged from each
contributor.
The FhG/Agere technology approach has been published in a number of AES and
other papers so that researchers have been able to evaluate claims and build
upon each others work. It is assumed that on-air tests with normal programming
are a necessary part of any
evaluation process, and expect those to start within the next months. Radio
broadcasting is important enough to deserve this care.
EXCITING AND COMPELLING!
Multichannel 5.1 surround creates an impressive theater of the mind – something
that must be heard to truly appreciate. Imagine turning a Production Director
loose with the power of additional audio channels on station liners, sweeps, and
promos. Even commercials will sound exciting. Just think about all the
possibilities with a multi-person morning show. The use of the surround channels
offers endless creative possibilities that will stimulate live on-the-air bits,
and morning show routines!
And music…Have you heard any of the DVD-Audio or SACD discs? Those WILL take
your breath away! The re-release of many classic albums has brought new light,
appreciation, and enjoyment by hearing them presented in an environment that
actually draws you into the sonic experience. To name a few: Steely Dan’s
Gaucho, Elton John’s Goodbye Yellow Brick Road, The Who’s Tommy,
REM’s Automatic For The People, Roxy Music’s Avalon, and Fleetwood
Mac’s Rumours are a small sampling of discs that will leave you not only
wanting for more, but making a trip to the local audio store to outfit your
living room in 5.1.
Getting this music on the air will make exciting radio. Are you aware that it’s
not possible to buy a 2-channel stereo receiver anymore? Think not, walk into
your local Best Buy or Circuit City and try to find one. All they’ll have are
stereo boom boxes, as everything else is multichannel. Audio stores say that 90%
of their customers ask for multichannel sound equipment by name. That’s
compelling onto itself. The 5.1 surround audio that accompanies DVD movies and
videos has conditioned early adopters to a multichannel world, and
this is rapidly spreading to the mass audience. How many times have you noticed
the crawl that’s posted at the beginning of primetime TV shows, or movies that
says, “This program is broadcast in 5.1 Surround Sound.”? It has grown
considerably. Most video and computer games now offer surround sound as well.
Realize that this last statement refers to a whole generation of young people
who now consider multichannel audio standard, just as this 1956 model
year writer considered stereo as a standard for so very long!
Acura, Cadillac, Volvo, Mercedes, and Lincoln have already announced 5.1
surround with DVDAudio/ SACD players in their up-scale 2005 models. As happened
with FM Stereo, this will work its way down to all automobile models. Hyundai is
going to offer 5.1 in an upcoming model as well. Thus bringing the availability
to the masses that much sooner. The auto industry is moving in this direction
because consumers want it.
Radio broadcasters MUST migrate into the surround world, or they will get left
behind. Remember how that AM became a stepchild once FM stereo was universally
accepted in the late 1970’s. All of terrestrial radio is now at risk due to the
advancement of technology
because the consumer has more exciting alternatives to listen to, and many
involve surround sound. We must advance FM radio if we want it to remain
interesting to consumers. Program content needs to be compelling as well, that’s
a given. But now we’ve got a technical reason to get excited about radio again,
and it will inspire new and compelling programming – just as FM stereo did when
it was a fresh technology.
THE WOW FACTOR…
We, as an industry, need to adopt the following mindset: Create enough of a
WOW factor in the mind of the consumer, that it compels them to purchase a
digital radio. The HDAM system offers a wow when comparing the HDAM signal to
conventional AM audio. Adding distinct 5.1 audio is the killer app that
puts the wow factor into the HDFM system. This is what it will take to motivate
the average consumer towards HD Radio®. This will be their vehicle to hearing
exciting radio once again. Just flipping the HD Radio® switch to ON will not get
it done alone. Consumers already have many more exciting alternatives to choose
from. Adopting a distinct 5.1 multichannel system for FM helps level the playing
field, and creates the opportunity to win back lost listeners.
WHAT’S NEXT?
If you’re convinced, then what’s next? When can we crank out this cool
excitement? For this to happen, only a few key sectors need to hear and act on
this: the record labels, broadcast executives, iBiquity Digital Corporation, and
the receiver manufacturers.
5.1 CONTENT NEEDED
The record labels must provide more 5.1 content. This shouldn’t be hard. There’s
already a lot of surround available, and with the incentive of radio’s promotion
capabilities, all new releases should be in the surround format, as well as
stereo. Just think about the vaults that are filled with multitrack master tapes
of classic
recordings that can be remixed into 5.1 and re-released again. The artists
and record labels stand to make millions on the re-issues alone. The record
labels win, as they have a new revenue source from material they already have,
and right now they probably are not even aware of the millions they are sitting
on. This is the same thing that happened when the compact disc evolved. This
creates a general excitement involving a new music format that will draw people
back to record stores. DVD-Audio and SACD multichannel are available for
consumers now, but record labels need radio to help them promote these new
disks. This is a no-brainer. As Nike Corp would say, “Just Do It!”
At the time of this writing, discussion has already opened with syndication
firms about creating 5.1 libraries that comprise the top 1000 titles in each
radio format. This would immediately help jump-start the ability to launch 5.1
programming, while the labels get online with new and re-releases.
BROADCASTERS TO-DO LIST
Radio broadcasters need to perform two significant functions: Adopt this tech by
installing it, and then promote it! Remember how many station ID’s used to say
something like “101, WMMS-Cleveland, in FM-STEREO!” That was how radio
subliminally conditioned us to “stereo.” Well, time to re-enact that discipline
again: “100.7, WMMS-Cleveland, in FM-SURROUND.” Also, radio can easily tie in
with audio stores to promote surround sound. Live remotes from audio outlets,
radio give-aways, along with advertising to help tell the story and raise
top-of-mind awareness in consumers. After all, the consumers are broadcasting’s
ultimate customers.
Recently, a Vice-President of Technical & Capital Management with a major
broadcast company, was quoted regarding 5.1 for radio, “The biggest breakthrough
will be 5.1 surround sound using IBOC or similar digital technology. To compete
with new methods of delivery, especially the ubiquitous DVD, I believe 5.1 will
be key to radio remaining competitive, both in the home and in the car.
Consumers have grown to expect this level of quality.” A prime example of
someone who not only gets it, but can see how this tech
is needed in order for radio to compete and survive.
MAKING IT FUN AGAIN!
Think about it, WE as an industry can actually inject life back into radio. Make
it fun and exciting again! Consider that line from the wonderful movie Field
of Dreams: “If you build it, they will come.” We need to build this, so that
they’ll come...back! We’re losing
listeners to many alternatives, a trend that will continue if we don’t act. We
have a chance NOW to breathe new life into our medium. Finally, a killer app
and a compelling reason for listeners to buy digital radio receivers, and a new
reason to listen to radio again.
In closing, broadcasting needs to evolve with the changing world, instead of
maintaining the status quo. Both XM and Sirius have the gear in place to switch
on 5.1 surround today. Also, the tech is available today to stream 5.1 surround
via the net at competitive bitrates.
It's a matter of the radios becoming available, and that's in process too. Even
if we start off multichannel transmission using tricked up methods for the
surround, it will eventually get picked up by the consumers, just as it did with
stereo in the 1960’s. There's also development going on that will enable the
iPod world of having surround in their players and in headphones.
Using a famous Scott Shannon phrase from the Z-100 Morning Zoo, “If it’s too
loud, you’re too old!” Well, we need to inject life back into radio. Adopting
distinct 5.1 audio is just the right dosage of audio channels to excite the
patient. If we follow this suggested path, it’s
quite possible that radio listener’s will remember another great slogan from
Z-100…”Lock It In, And Rip The Knob Off!”
ACKNOWLEDGEMENTS
HD Radio is a registered trademark of iBiquity Digital
Corporation.
Ing. Wolfgang Fiesel
Group Manager Audio Systems
Fraunhofer IIS
Multimedia Realtime Systems
Erlangen, Germany
Steve Church, President
Telos Systems
Cleveland, Ohio