A little break from politics, if you don't mind.

If you read Bob Dylan's rant about modern music today, he sounds unhinged. He isn't; he just isn't describing what he means very well, or it went over the reporter's head and didn't get on paper.

To understand what he means, you need to know what a "compressor" is. (Bear with me here.) In the audio world, a compressor is a device that takes incoming audio above a settable threshhold and mashes its dynamic range, again to a selectable extent. It is useful for making sure a singer's high notes aren't ten times louder than her low ones, and in many other ways, from getting tight drums to punchy bass to overdriven guitar.

Turn the "ratio" way up, and the sound really starts getting mashed together. You would recognize it immediately: "Oh, now it sounds like a radio". This is because radio traditionally had a limited signal-to-noise ratio, and the louder you could mash everything together, the more clearly everything could be heard. So compressors have always been used at radio stations for this purpose.

Compress things far enough and they actually sound "louder" to the ear; everything is squished into a very narrow dynamic range, all loud. In the last couple of decades it has become fashionable during the mastering process to heavily compress the final product, for what reasons who can say, because it sounds like crap, just as Dylan says. He hears the unmastered version in the studio, then compares it to the CD which is sonically squished, and rightly hates the sound - there's "sound all over it", as he says.

You read that right - producers purposely defeat the dynamic range made possible by CDs. In fact, CDs today in general have less dynamic range than vinyl albums did, for just this reason.

Now I am guessing here, but I'd lay odds that when Dylan is griping about the sound, this is what he means.

So now you know why your CDs with their pristine signal-to-noise ratio sound like crap.