I tuned into XM Radio’s Sonic Theater recently, and had to turn it off.
Don’t get me wrong, I love the channel. A national channel of contemporary audio theater? This is an amazing accomplishment for a medium they used to call dead. And many of the productions they air are wonderful. So wonderful, in fact, that many of them are also in the catalog.
The reason I turned it off was because of the sound — namely the compression.
Two kinds of compression.
The first is compression of dynamics. Sound has both loud bits and quiet bits. This occurs both in the long term — someone shouts, then whispers, or somone bangs a drum, then a bandmate plays the flute. And it is also in the short term, a snare hit, then the quieter bit of guitar, and a beat later another snare hit. This kind of compression makes the loud bits not so loud. Use it some, it can cure a lot of sonic ills, use it too much, you often end up with mushy sound.
So why use a lot of it?
Well, once upon a time, you could make things louder by recording it louder on you magnetic tape. When you push the maximum volume on magnetic tape, it pushes back. But not too hard. Magnetic tape overloads relatively gently, and sounds, actually, rather nice with a little bit of overload.
Then along came digital. Digital recording and digital transmission. With a finite number of digits, when you hit the maximum, that’s the maximum. When you push digital, it stops you like an NFL defensive front line stopping a junior high school quarterback.
Somewhere along the line people got the idea that it was good to be loud. And they got the idea that it was good to be louder than your neighbor. His song is loud. Mine must be louder. His station is loud. My station is louder. But how to do that in a digital world?
That’s right, compress it.
You see, if you make the loud bits less loud, you can turn the whole thing up, and the whole thing is louder. The only thing you lose is dynamics.
And thus began the loudness wars.
And that has made the whole recorded world sound like mush. And it is so pervasive, nobody seems to question it any more.
The second kind of compression is bandwidth compression.
In digital, bandwidth is the ammount of bits you must store, or process, or transmit to get your information across. You can reduce the number of bits by a factor of 10 or more, if you do this, but only if you do what is called “lossy” compression. Lossy compression is where you throw out bits of the sound you don’t think the listener will miss. MP3 is lossy compression. And it sounds pretty good, if done right. Most people don’t hear the difference.
But some do.
And the more you compress it, the more you lose. And to squeeze more and more channels out of a satellite, you compress it more.
And you lose more.
And now everyone can hear the difference.
And often, if you’re transmitting voice rather than music, you compress it even more.
After all, its only spoken word, right?
Now everyone really hears the difference.
So, I turned it off.
Good thing I’ve got a big room full of gloriously uncompressed CDs.