Mastering EQualizer Technique
Goals of Equalization
The two main goals of equalization in mastering are as follows: correction and enhancement. Correction is either used to reduce an unaesthetic buildup of frequencies in a specific part of the spectral range, or change the volume of a specific element that for whatever reason cannot be corrected in the original mix. Corrective functions are often best executed with digital, linear phase equalizers due to their inherently transparent nature. Equalization for enhancement is used to increase apparent size, closeness, excitement and volume of a mix, and is generally best executed with analogue filters and shelving equalizers.
Corrective equalization is almost always first in the signal flow, before equalization for enhancement, compression and limiting. Equalization for enhancement can be inserted directly before or after a mastering compressor, with before being the most common location. In modern audio mastering, digital limiters will essentially always be the final insert in your signal chain. Many limiter plugins contain built in equalization functions which can be used for convenient final eq tweaks.
Because of the transparency and ease of equalization plug-ins, most corrective eq is executed directly in your daw before sending to your analogue chain. The most common modern plugins for mastering are the DMG Equilibrium and the FabFilter Q2. Both offer linear phase and mid/side settings. The DMG Equilibrium offers a wide variety of emulated analogue curves and is in daily use in my personal work flow.