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Wednesday, September 14, 2005

I have been comparing the sound quality of XM radio recently, and came to a fairly shocking realization that sound quality standards are not what one would normally think.

I have a trusty Delphi "SkyFi" XM radio that I use in the office, but not too long ago XM allowed all its subscibers to use its streaming web radio service for free. ("Free" -- that is, they raised the monthly rate but threw in the web service at the same time.) It's the same channels, only they are transmitted through WMA9 streaming audio to your web browser.

Interesting discoveries:

1. The WMA9 stream is significantly more detailed, especially in the high end. I was shocked at how much detail I had been missing.

2. Nothwithstanding, the SkyFi sounds better.

How can that be? The SkyFi seems to have been designed to eradicate a very particular problem with XM radio -- and with all streaming audio that is highly compressed. (XM radio is 64kbps, but it uses an algorithm that is supposedly superior to MP3.) The very high-end sounds like crap -- "artifacts" everywhere. And by "artifacts," I mean that cymbals sound like someone going "chhhhh" into a Mr. Microphone. All that distortion comes through crystal clear in the WMA9 stream.

The SkyFi seems to have been designed to roll off the high end frequencies to make the whole thing sound a lot more like FM radio. And it does -- it is very comparable to FM, just with a whole lot more selection. FM is no leader in sound quality, but it works just fine. And the SkyFi spares you that distortion, and the detail that comes with it.

That is why I am a little dubious of the claims behind the new wave of high-end XM or Sirius tuners, who claim to have better sound quality. Beware the attempt to make more out of this audio stream than it can handle.

No idea why I decided to pass this along. Perhaps just trying to add to humankind's knowledge.

 11:16 AM

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