GregHeadley.com

The art of mastering

I've been having some music professionally mastered recently, for a coming CD release, and it's been a great learning process. I've been involved in pseudo-mastering projects before, but having a pro do the work, someone who listens critically with skilled and experienced ears, is a first for me. The science of mastering is in many ways a mystery, and not just to me. I certainly know now that it's more than just having someone set a brickwall limiter and crank everything up to 11. I listen to a lot of music with substantial amounts of very high frequencies, like at least 14khz and up. My ears are so used to it (or maybe fried from it) that I don't always notice how harsh those frequencies can be and how much they can fatigue the ears. My mastering engineer pointed this out as a potential problem right from the start. Now this is what I need: someone knowledgeable to listen and tell me what the problems are. At his suggestion, he made one mastering run with no low-pass filtering or EQ and a second one with a brickwall LPF at 16khz and some EQ tweaks from 12-16khz. His analysis of the tracks had found measurable energy across the frequency spectrum, all the way up to 22khz. We humans don't hear that much over about 16khz, but those frequencies do have an effect on the more audible spectrum. Very high frequencies can obscure the clarity of other frequencies or make everything sound harsh (especially when it's all digital). I'm evaluating the versions now, and his idea to filter those highs was definitely a good one. I listened to the no LPF version at a somewhat high volume, trying to listen critically to the high tones and found that those frequencies really did wear on my eardrums quickly. A nice surprise with the filtered and EQd version is that the quality of some sections was improved by the reduced highs, even when they weren't audibly present. Some parts have more presence in the mid and low frequencies now that they aren't masked by those sneaky highs.

In all, I'm happy with the outcome. I used almost no compression in the recording and mixing and no compression was used in the mastering. The music has a wide dynamic range with many layers that I hope will reward attentive listening. There was also some stuff about DC offset and normalizing and RMS power that I managed to glean from the process. I know what mistakes not to make next time.