All music has “dynamic range,” variations in volume between the loud parts and the soft parts. People sing and play at different volumes. Individual notes have an initial attack and then a gradual decay as they fade to silence. But most of the music you hear today–and by “most” I mean “everything except classical music” has been treated to have little or no dynamic range. It’s been “slammed” and “loudness maximized.”

Audio engineers manage this with something called “compression.” A compressor is a hardware or software device that sets a limit on how loud a piece of audio can go. It sets a top range, and when the audio signal exceeds that point, it turns it down. Imagine you are listening to a piece of music, and a really loud part is coming up, and you turn the volume knob down just as that part arrives. It’s like that, only automated. How does this make things louder?

It lets you set an overall high level, and squishes everything that was over that level down. So let’s imagine a piece of music. “Ten” is the maximum volume of the loudest parts. The singer is screaming: it’s really loud. And three is the level of the quietest parts. If you increase the volume level so that the quietest parts, formerly 3, are now at 10, and the compressor is squishing the loudest parts so they stay at ten, the result is a recording that comes to your ear at ten and only ten. The hushed and quiet passages are just as loud as the crescendo. Imagine that a whisper and a scream are the same volume. That’s modern music.

Here’s an excellent illustration on video 

Why would anyone want such a recording? Well for one thing human beings hear “louder” as better. If you play two identical pieces of music, and turn one up only very slightly, people will inevitably hear the louder one as better. Salesmen still use this trick to sell audio–turn the more expensive unit up, and it will sound “better” to everyone. For the last twenty tears, music has been getting more and more compressed, more and more uniformly loud.

And here’s a visual explanation, from Wikipedia’s excellent entry on “the loudness wars.” It’s pretty clear, showing the ZZ top song Sharp Dressed Man as it was issued, and than as it was “remastered” for reissue as a digital file. Watch the animated gif. The first version has little spikes in the waveform, but with each remaster it turns more and more into a solid block of sledgehammer volume

The reason you might prefer vinyl records is that you simply can’t do this kind of thing with a record. A record turns sounds into grooves in vinyl. As the sounds get louder the grooves swing wider. If the grooves are too wide, too loud, either the needle will jump out of the groove or you won’t be able to fit all the music on the record. So there are physical limits on how loud a record can get. Susan Schmidt Horning describes the process here.

Vinyl records have more “dynamic range,” more variation between the soft parts and the loud parts. Which in turn is closer to how we experience sound in the natural world. If you compare an old vinyl record to a digital remaster, you’ll hear the difference right away. The rule of thump on a modern recording is that you can’t have more than about 2 db of dynamic range.

Digital music doesn’t have to be loudness maximized, and in fact lots of recording engineers want to find a way to stop the tendency. You can celebrate “Dynamic Range Day” and find an index of the dynamic range of thousands of albums.

If you find yourself preferring vinyl, dynamic range is probably why. It’s worth speculating why we create for ourselves a musical landscape crushed an hyped into a impossible level of consistency.