The Digital Radio File
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Is digital radio finally coming? In some countries (including Canada) it is already, officially, here. No special digital broadcasts are being produced, but existing programs are being simulcast on digital. And at least one company (Arcam) has a tuner to pull these broadcasts in. But what are the chances you'll like what you hear?
Not so good.
We outlined some of the reasons in UHF No. 59: digital radio uses brutal compression, which throws away most of the data, in order to save bandwidth. We thought that was a high price to pay for digital's fade-free performance. In fact the price to be paid is even higher.
The important thing to understand is that broadcasters don't care about what they're putting out on digital. With just one tuner brand out there, plus a tiny handful of digital car radios, they know that their office waiting room has more listeners than the entire digital band.
They do care about digital itself, though, because it is streamlining the jobs their production people need to do, and therefore maximizing profits. A lot of the station functions that were once analog are now digital.
An example is the station cartridge. Until recently, all stations used endless loop broadcast cartridges for ads, program themes and production elements such as music stingers and station identification. These cartridges look like the 8-track cartridges you see in garage sales, but are actually similar to the 8-track's ancestor, the 4-track cartridge common in the 1960's. In many stations, they have been replaced by Sony's MiniDisc.
And that's a problem. MiniDisc, like digital radio itself, uses a lossy codec (compression-decompression system) called ATRAC. But although ATRAC and Musicam (the codec used in Canada and much of Europe) discard a similar amount of data, it is not the same data. And so ads and other material from MiniDisc winds up being processed twice.
If you visit a modern radio station, you'll discover that, in that environment, razor blades are for everything except cutting tape. Sound editors now do their stuff at DAWs--digital audio workstations. These computer-based production centres began in newsrooms a decade ago, but now are occupying more and more space in the stations' programming. Some DAWs use linear pulse-code modulation, like the CD, but many do not. The bigger the system, the greater the probability that it buys extra bandwidth and storage space with lossy compression. No system we know uses Musicam.
The promise from the early promoters of digital broadcasting was that the radio station of tomorrow would be all digital from the microphone all the way to the listener's receiver. This has not happened. Radio mixing consoles are analog, and so the digital production material is converted back to analog before being reconverted to digital through another lossy system.
All right...let's suppose you don't care about ads or even station IDs, you're in this for the music. What's the deal there?
Our sources tell us that there is bad news there too. Few stations outside of college campuses still have actual disc jockeys who choose their own music. Virtually all stations have highly automated playlists to ensure proper rotation of the records chosen by their music programmers. These systems are digital, and have been for years.
Some of them use compression. Yes, their signal is turned back into analog before being broadcast.
Some stations emphasizing new music are turning to minor artists, who distribute their work via the Internet with such organizations as MP3.com. As you no doubt know, MP3 is the most brutal of all codecs, discarding more than 90% of data, leaving essentially what would be left if you listened to music on a boombox. Queuing MP3 up with Musicam gets us increasingly far away from "near CD quality."
Add to this the imprudence of station staff that is not technically savvy, who may produce a new Minidisc by mixing elements from existing MiniDiscs...through the analog domain. Don't be surprised if what gets through sounds like oatmeal cooked in a double portion of water.
If station management doesn't care, it's because no one's listening. Truth to tell, we don't care either, because we think digital radio as it is developing today is going nowhere.
What is sadder is that these galloping codecs, pervasive and incompatible, are diluting the already thin quality of analog FM. That we do care about. We know, however, that audio quality is not Topic A in broadcasting company boardrooms.
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