Know your enemy: Dynamic Range Compression

DSC

More and more bands are releasing limited editions of their albums on vinyl. This is not just to meet a demand from the nostalgic who enjoy the physical packaging and feel of an LP more than a CD. These days it is generally true that music sounds better on vinyl than on CD.

It shouldn’t. With the great advances in digital sound technology, a CD or high-quality digital music file should sound identical to the best-quality analog recording on vinyl – to the human ear, anyway.

There’s a big problem with a lot of digital music, though. It’s called Dynamic Range Compression (DRC).

This blight, DRC, emerged during the “sound war” that started in the 1990s. Recording companies wanted their albums to sound louder than the rest. They pushed the levels to increase the recording volume. They still do it. Maybe they feel they have to because everyone else is doing it too. Good lord, we can’t have our band sounding softer than theirs!

What DRC does is eliminate the quieter passages that add contrast and depth to the technical production aspect of a song. This causes the stronger sounds to stretch into the distortion range. The studio addresses this by clipping the recording to fit within the range of (supposed) non-distortion.

The result is that modern digital recordings tend to be as flat as an airport runway. The peaks and troughs, the mountains and valleys that the band plans into its music, are filled in, levelled off or chopped down.

Some say this is a good thing. You don’t have to adjust the volume when you’re listening to your music in a noisy environment like a train, an office or your old clunker of a car that needs new piston rings.

The marketers tell us most people won’t notice the difference, although there would be very evident differences between hearing a live performance of a song and listening to the same song after it’s been through DCR.

I looked at the “maps” of two Metallica songs in the free (and very good) Audacity sound editor. Here’s “Master of Puppets” (1986). Notice how the loudest sound reaches just to the edge of the normal, undistorted sound range.

MasterOfPuppetsSW

 

And here’s “Hell and Back” (2011). See how few softer passages there are – no more than a few seconds each. The sound has been pushed to the max, and the over-sound has been sliced off.

HellAndBackSW

Now listen to both songs. Maybe you won’t hear much or any difference. Or maybe you’ll wonder if it’s just the music and not the recording technology that’s changed the sound of Metallica over the years.

By the way, don’t always rush to buy the remastered version of an old album. “Remastered” doesn’t necessarily mean “sounds better”; it could just mean “much louder”.

 

 

 

 

 

 

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About ChristopherMammal

I've made it to Mammal. I still hope to be classified as Human one day. Meanwhile I have evolved enough to recognise different types of music as well as the shrieks of certain vervet monkeys who are known for their scurrilous behaviour in the proximity of unguarded bananas.

Posted on August 22, 2014, in Ramblings and tagged , , . Bookmark the permalink. 4 Comments.

  1. I’m bummed that so many albums are falling victim to the loudness wars. I use Audacity as well, and it makes perfectly obvious how bad the situation is. So many albums I love don’t sound like they should, the latest by Kiss and Ace Frehley being good examples. What a shame that nobody seems to care about sound quality anymore.

  2. Great post! As you know, this loudness shit annoys me to no end. I have a volume knob and I’m pretty sure I’ve figured it out for the most part (I still have trouble remembering if clockwise is louder or softer sometimes). A good handful of releases I picked up this year on CD bucked the trend hand have some outstanding sound (Agalloch’s The Serpent and the Sphere is an audiophile’s dream). I’ve noticed a lot of the more ‘brutal’ releases, especially from the -core community, are abusing this to no end. It’s sad. I’ve even seen artist defend the fact they wanted loud levels saying that all the elements of a song should be on one wave length. Boggles my mind.

  3. Also, those peaks you see in the soundwave, that’s usually they drums, also known as the backbone of a metal song (or pretty much any rock song in general). Why would anyone want to weaken their backbone? Good natural sounding drums can make or break a song IMO. Do you think that Epic drum fill in In the Air Tonight would have been as impactful if they didn’t pop above the rest of the song.
    The sound/recording engineers are pretty much just as important as the artists writing the music. Pretty much a member of the band.

  4. ChristopherMammal

    It’s reassuring to know that knowledgeable guys like you share my sentiments about DRC. I’m going to do an experiment with audacity and post the results here — an excerpt from some classical music before and after sound-pounding.

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