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Hear That Xylophone!
Many audiophiles dispute HD Radio's quality: I don't want to get into a debate over very fine points, because audiophiles who say that HD Radio is not "CD quality" are absolutely correct. One person has proposed calling it "MP3 quality," which is more accurate, but not correct, either. HD Radio has a far higher dynamic range and frequency response than analog FM, which means that you can hear both deep and high notes better, while also hearing the original sound reproduced with greater fidelity for loudness and softness.
While HD Radio isn't CD quality, partly because it's a compressed format, it does have the range of a CD. It's not MP3 quality, even though the digital radio compression uses a 96 Kbps encoder that's similar for primary FM multicast channels. Why isn't it the same? Because of two factors. First, iBiquity chose a set of optimizations that are designed to make this compression work over the radio. Second, radio stations with any know-how are using preprocessing to optimize their sounds into the compressed format. This allows weaknesses in the compressor to be overcome through clever, real-time choices in the preprocessor. It also means that two stations broadcasting the same song might sound somewhat different.
In this Star-Telegram article about HD Radio, a radio program director suddenly hears the xylophone in a Sly and the Family Stone song--he's been in radio so long, he'd forgotten that these very high, pure notes really exist.
That's my experience, too. When I listen on headphones or in a room to an HD Radio broadcast, it seems spectacular in comparison to analog radio. A CD will always be better, because it's uncompressed sound, so your CD player makes all the choices, not the compression algorithm. But satellite and Internet radio won't sound any different, and may sound worse, especially Internet radio that's using less-than-ideal compressors and have limited bandwidth.
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Comments
Please everone: take a decent pair ofheadphones to a nearby satellite radio: their high end squirms and the imaging is disturbing. If your ears are good, satellite is bad right now. HD radio did not trash the phasing of their high end...the soundsatge is a dite better than the original FM-stereo soundstage. This is a crucial difference if you are an audiophile with decent ears. I cancelled XM...at home I couldn't stand the sizzling and flaring artifacts.
Posted by: leonardo menderes | December 15, 2006 11:53 AM