07/05/2024
The Mastering Difference - Phase Alignment and Phase Rotation
Many engineers think that you can simply slap a mastering chain on a track, tweak to taste, and achieve great results. While this will undoubtedly make a great difference in your track, there are limitations that will keep you from reaching that professional polished sound.
The reality is that before a track even begins to be mastered, the issue of phase alignment and phase rotation must be addressed. Think of a limiter as a balloon, and your mix as a porcupine. The goal (in most cases) of end stage limiting is to get the porcupine as close as possible to the balloon without popping it (popping the balloon would be equivalent to causing distortion).
The porcupine has long quills on its back, and short quills on its belly. Therefore, if we “rotate,” or flip the porcupine on its back, we can get the porcupine closer to the balloon without popping it. We have not changed anything about the porcupine, only how it approaches the limiter and converters.
Most limiters, converters, and other mastering grade hardware are optimized for content at a phase alignment of -2. Most final mixes I receive from even experienced engineers have an average phase alignment of 20-70. These must be run through a phase analyzer, and rotated to an alignment of -2 before processing begins.
This has no impact on the loudness of the track, but can introduce an artifact called transient smearing. This is due to the mix engineer monitoring the attack of the transients through the original phase. The good news is that modern technology allows us to process transients separately. Thus, we can apply phase rotation to all content but the transient. This gives us the best of both worlds, transient crispness, and greater headroom in the rest of the mix pre-processing.
Another example of why hiring the right engineer is critical to achieve the best end result possible!
