Angry Metal-Fi: Level Matching Your Life

Angry Metal-Fi is a series of articles that are cross posted on Angry Metal Guy and Metal-Fi as a collaborative effort to evangelize dynamics in metal.

By: Alex-Fi

Angry Metal-Fi“But I like my metal loud. It just sounds better to me.”

This is bar none the number one reaction I get from fellow headbangers, who after they read one of our articles, go off in a frenzy and measure all their record’s dynamic range only to discover they almost always prefer the hyper compressed albums over the dynamic ones.

Not surprising. In fact most of the time, their results only reinforce why the Loudness War exists in the first place. Let me explain.

From a strictly Darwinian standpoint, the ability to hear is critical to your survival. It allows you to perceive the natural sounds in your environment to find food (as well as avoid becoming it), keep our balance, and most importantly in this day an age, communicate with your fellow headbanger more effectively. Consequently, your ears have developed into a highly sensitive instrument. You have the ability to hear a whisper in a sound proofed room as well as detect the loudest scream at a Pig Destroyer show. Putting that into numbers, the human ear has about 140dB of dynamic range (the CD is only 96dB) and can hear up to three orders of magnitude in frequency (20Hz – 20kHz).

However, the perceived response of human hearing is not linear with respect to frequency. In English, the apparent loudness of a sound depends on its frequency and intensity. As I stated in my previous article, the study of how our ears perceive sound with respect to volume was first researched by Fletcher and Munson back in 1933. They came up with the first Equal-loudness contour, a plot that shows how your hearing changes depending on a sound’s intensity (sound pressure level or SPL). The curves are measured in Phons which is the value of SPL that has constant apparent loudness for average human hearing.

Fletcher-Munson Curves

Fletcher-Munson Curves

Looking at the graph above, imagine you are listening to Bolt Thrower at 80dB. Your head is moving back and forth as the British made tank steam rolls over your eardrums. Life is good. Then you turn the volume knob down and play the same song at 10dB. Take a look at the frequency disparity between the two. At 10dB, anything below 500Hz is pretty much a wash (sorry Jo). Also note how bass (less than 250Hz) and treble (greater than 2kHz) dramatically change in general depending on SPL. That’s why at 80dB, Bolt Thrower sounds richer and fuller than it does at 10dB. Your ears literally hear more of the frequency spectrum. This graph also explains why historically speaking, most engineers tend to stay around 85dB when they perform their magic, since that’s where the Equal-loudness contour tends to be the flattest.

Armed with this knowledge in mind, you understand now why louder generally sounds better. That’s why it is absolutely imperative that when you decide to sit down and compare two pieces of music (say your original Septic Flesh records versus the recently released remasters) that you level match them, i.e. you compare both pieces of music at the same volume. Otherwise your ears will be fooled into thinking one sounds better than the other when in reality it’s actually the reverse.

The two most widespread technologies that allow you to level match your music are ReplayGain and Sound Check. ReplayGain is the most prevalent of the two since it is supported by a myriad of players on Windows, Linux, and Mac. Sound Check is the name Apple uses for the equivalent technology built into their venerable iTunes client. Both basically do the same thing and work almost identically.

Both technologies analyze a track or entire album to calculate the material’s peak levels and perceived volume. Then based on a configurable target value (how loud or soft you want the music to sound) another calculation is performed to determine how much gain or attenuation should be applied to the music to hit that target value during playback.

Please note, no samples were harmed in the making of either the ReplayGain or Sound Check values. Neither of these technologies degrade or modify the source material in anyway. The calculated gain value is typically stored as metadata (usually an ID3 tag like the ones you use for album, artist, track number, etc.) so a supported client can read back the number and apply normalization upon playback. Think of ReplayGain and Sound Check as an invisible hand around your volume knob, rotating it up and down to keep your perceived volume consistent across different source material. If you are interested in finding out how to use them, please check out my detailed article here or Google around – they are both fairly straightforward to use.

At this point you maybe asking yourself, why am I so against the Loudness War? Doesn’t dynamic range compression and brickwall limiting make the music louder which means it will sound better? Right?

Wrong. There is a major difference between manipulating the recorded volume versus the playback one. When a mastering engineer artificially pushes the volume higher by applying massive amounts of DRC, he or she is changing the recorded volume by squashing the high and low ends of the frequency spectrum. This process has the nasty byproduct of causing transients and imaging to substantially degrade, making the music sound lifeless and dull. Take a look at the same track level matched with itself taken from two different masters off the same album (by the same mastering engineer no less):

CD mix (top) and vinyl mix (bottom) level matched

See all those peaks on the bottom vinyl mix, those are kick drums, cymbal crashes, transients, etc. They have been completely chopped off on the top digital mix in order to maintain volume homogeneity. There is just no longer any room left for them to exist. Simply put, hyper compression sacrifices fidelity at the expense of volume and irrevocably damages the original recording. Read Dave’s “Take the Swanö Challenge” article for the complete lowdown (even better, take the challenge yourself).

However, turning the volume knob up or down, like in our Bolt Thrower example above, doesn’t affect the music’s dynamic range or fidelity at all. The original recording is preserved since you are only changing the playback volume. As a result, you can feel confident that no matter what volume you ultimately decide to enjoy the music at, you’re not damaging it in the process.

Do you think the folks I mentioned at the beginning of this article level matched their hyper compressed metal records with their highly dynamic counterparts? Almost always the answer is no. They are not alone though. The overwhelming majority of reviews I read online rarely ever talk about level matching when discussing a remaster or remix. So how can you trust a review that is touting how amazing a remaster sounds if the author did not level match it with the original? Simple, you can’t.

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