Mastering EQ vs. Dynamics Processing

What actually happens during a mastering session? While many mastering engineers regard the “voodoo” of their art as trade secrets and make clients sign a statement to that effect, I’m more than happy to share what goes on behind the curtain.

Mastering is considered a kind of “black art” practiced by engineers blessed with “Golden Ears”. Some of the best mastering engineers are currently or have been musicians in the past. I know Bob Ludwig at Gateway Mastering was a horn player (those in the know never say “French Horn”…it’s just the “Horn”). I think it’s tremendously important the mastering engineers have a musical background. Would you want some knob-twisting, button pusher left hand brain guy putting the final timbral adjustments on a project that you’ve worked on for many months? I know my clients always felt better that I had such a diverse musical background.

The mastering session is where all of the final mixes are sequenced and tweaked into their final form. A single final “studio master” is created and released to waiting fans and promotion professionals. The one-size-fits-all strategy still rules the commercial music industry.

Two of the most critical steps undertaken by the mastering engineer (in consultation with the mixing engineers and producer) are the application of equalization and dynamics processing. EQ is basically tone controls…only in the mastering studios of the world, they are very expensive, very flexible and very powerful. It’s what we all think of as bass, mids and treble controls…only better. Dynamics processing involves adjusting the overall and relative volume of the tunes or even the internal loudness contour of the albums tracks.

I am a serious believer in the mild use of EQ to bring out subtle elements of a mix or polish off the harshness of an overly bright vocal track. One of my favorite “tricks” is to give about a half dB boost at the first formant frequency to bring the lead vocal into relief. For the male vocals that happens at about 1300 Hz and for females it’s slightly higher at around 1600 Hz. This is the frequency that makes sung lyrics more intelligible…and it never fails to impress the artist and producers.

Other applications of equalization can be applied to the low end of certain tunes to make them consistent with the other tracks. I often shape a snare drum hit at 150 Hz and 1000 Hz to bring out the “snap” of the drum if I think it’s too dull. And of course, there has to be room for it amongst the other instruments. A slight bump at 5 kHz and again at 15 kHz will add some “air” or openness to a track. There are equalizers that have controls out to 40 kHz which engineers use to provide “sheen” or a “glassy” tone to a track.

There are lots of new digital “equalizer type” plug-in in that are on the market these days. They do some interesting things to the harmonic structure of your tracks. Some modify the phase alignment of upper partials to “cloud” the sound make it warmer and others boost the “apparent” level of a certain frequency range by changing the amplitude of only selected elements.

Masterizer was originally an April Fool’s joke by Funklogic but is actually a real plug-in now that “adds low quality effects (static, hiss, etc) to your audio as you fiddle with the controls.” But it does get applied to commercial releases. If the mastering engineer applies it and the producer likes it then you’re good to go.

Following these careful and surgical EQ adjustments, the mastering engineers will begin to apply dynamics processes to the project. We’ll talk about Ultramaximizer, brick wall limiters, side chain compressors and the like tomorrow.

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Mark Waldrep, aka Dr. AIX, has been producing and engineering music for over 40 years. He learned electronics as a teenager from his HAM radio father while learning to play the guitar. Mark received the first doctorate in music composition from UCLA in 1986 for a "binaural" electronic music composition. Other advanced degrees include an MS in computer science, an MFA/MA in music, BM in music and a BA in art. As an engineer and producer, Mark has worked on projects for the Rolling Stones, 311, Tool, KISS, Blink 182, Blues Traveler, Britney Spears, the San Francisco Symphony, The Dover Quartet, Willie Nelson, Paul Williams, The Allman Brothers, Bad Company and many more. Dr. Waldrep has been an innovator when it comes to multimedia and music. He created the first enhanced CDs in the 90s, the first DVD-Videos released in the U.S., the first web-connected DVD, the first DVD-Audio title, the first music Blu-ray disc and the first 3D Music Album. Additionally, he launched the first High Definition Music Download site in 2007 called A frequency speaker at audio events, author of numerous articles, Dr. Waldrep is currently writing a book on the production and reproduction of high-end music called, "High-End Audio: A Practical Guide to Production and Playback". The book should be completed in the fall of 2013.

3 thoughts on “Mastering EQ vs. Dynamics Processing

  • March 7, 2014 at 10:56 pm

    How does a person’s natural hearing, or lack of, effect their ability to master? For example at 57 years old, I have significant high frequency hearing loss in one ear. If I ran a mastering studio, would my finished product start to come out too bright if I unknowingly compensate for my ears difficulty hearing higher frequencies? What happens if someone with the “Golden Ear” starts to lose their hearing?

    • March 8, 2014 at 9:58 am

      Kenn…that’s very good question. The reality it that audio engineers spend a lot of their time in studios where the sonic levels can be excessive. Having good hearing in your fifties is the result of being careful, but the high frequencies are the first to go regardless of how careful you are. I’m about to turn 61 and had my ear tested about a year ago. They technician was very impressed with my results…stating that I had the hearing of a 20 year old. I think it has to do with knowing how to listen and what to listen for as well. I’m sure there are lots of mastering engineers that are audibly challenged…especially given that they make so many promising recording sound “punchy”.

  • March 18, 2014 at 2:33 pm

    I have followed with great interest your several explanations of the many steps and care (esp with AIX) which go into the production of a final product: the best possible recording of music. However, the vocabulary is not exactly familiar to me, much less the sequence of processes, and thinking of the old adage that “a picture is worth a thousand words” had the idea that you should produce a video of the actual making of a HR disk. Unlike with sausage, I would actually like to know how your great disks are produced.

    I’m sure you have no trade secrets unknown in the industry; it’s just that you choose to pay attention to the theory and the music – a combination of talents not likely to be duplicated. Go ahead and produce a “how it’s made”!


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