Mastering is a subject I've been interested in for a fairly long time now. I've always wondered how engineers would make mixes louder without clipping, even though the waveform looks like it is indeed clipping. I've also wondered how to make dialogue sound crisp and clear such as in the movies, and despite having done a lot of audio repairing, there's always much more to learn aside from it. Furthermore, although I'm not great with maths, I love to learn about audio science, and how both analogue and digital audio works.
Mastering take place in between mixing the audio and preparing to be replicated or distributed; it's the process of turning a collection of songs into a record by making they belong together, in term of tone, volume, and timing, which means the spacing of songs in an album (Owsinski, 2013). In the case of post production, it differs in that there's no album to be created, although the final product must meet the EBU standards.
What makes a professional mastering engineer is not only well trained ears, but also the room acoustics, speakers and hardware. What's common in the relationship between mastering and mixing engineers is that the later wouldn't be the appropriate professional to master a track or an album, since he or she will be biased as to what they should accomplish. By assigning the work to a mastering engineer, the product will be listened to with unbiased ears, as well as with a more meticulous attention to detail that the mixer might have missed.
It can be perplexing to learn that it's better not to apply too much EQ and compression in mixing, since in mastering the engineer would have a better time bringing the tracks to the required standards. I got befuddled by this idea although I understand its logic, and it does make sense -- if I received a project to master and I had to do way too much to improve the quality, the most conscious approach would be to send it back to the mixer to fix the issues.
Speaking of fixing, the art of audio repair also belongs to the mastering universe. Many people think that iZotope RX is exclusively a de-noiser, and that's not the case. In RX, the engineer is able to rebalance the levels of a stereo recording, restore audio dropouts--which is particularly useful in post-production--, remove thumps, clicks, crackles and really dive into frequency by frequency in a spectral view. It can even be used as a sound design tool, though that's a topic for another blog.
One aspect of mastering that I wish the unit covered is authoring, more specifically in relation to Dolby's requisites, as well as DVD and Blu-ray in the case of post-production. Now, taking nowadays circumstances into account, why would anyone bother to care about these things since students don't necessarily kickstart their careers in studios whose facilities feature Dolby systems? Well, you never know where you will end up and what are your clients going to ask you to do, right? So it never hurts to get more knowledgeable about your practice. That said, I think future students would certainly benefit from more advanced tutoring on mastering.
As for what I've learned, it was jaw-dropping to learn about the mid-side trick to remove unwanted noise from the centre or the sides -- I had never thought of mid-side with that perspective. I've also been confused about the differences between a compressor and limiter -- the one the raises the sound to a proposed threshold--, given that a compressor can also act as a brick wall limiter.
Imagine that the image on the left represents a typical DAW compressor. The difference between these two pictures is that the screenshot of the Waves L1 illustrates a brick wall limiter with the capability to boost the signal to a desired threshold while making sure that it doesn't exceed the specified ceiling. Conversely, the left image suggests a compressor with an option of just limiting the signal.
In addition to the aforementioned limiters, there are multiband compressors and limiters; that is, instead of compressing or boosting the whole signal, the user can apply the effects only on a particular set of bands.
When reflecting upon my creative practice after going through the tape and mastering projects, I think it'd be reasonable to take back what I said in the tape blog about preferring the sound of digital. While I do fancy a cleaner sound, I detest music that sounds too "perfect". I was listening to the soundtrack of Schindler's List today and couldn't imagine it without the hiss. In addition, the impurities of the score resembles the antiqued look of the film, so I wouldn't make much sense to remove them anyway.
One reason I enjoy classical music so much is because of its dynamics. The audio industry has been suffering from a loudness war for quite some time now, and music is only getting louder and louder. In an article for Sound on Sound, Emmanuel Deruty wrote that modern productions lack subtlety, and sacrifice quality for level. Have a listen at this track from Schindler's List. Notice how we can feel the tension, the hopelessness of the violin, played by Itzhak Perlman.
When my classmates and I were being taught about loudness, it was mentioned that the average LUFS applicable for general pop, rock and the like is usually -10 LUFS. The average level for podcast and audio book is around - 18 LUFS and I already find it loud -- well, acceptable loud. -10 is simply too much. From my perspective, today's society seems more interest in compression than in the experience of listening to music.
Learning about mastering was a true eye-opener as to how I approach my mixes. Yes, mastering for film is different but, after all, mastering is not only about making mixes louder.
Deruty, E. (2011). 'Dynamic Range' & The Loudness War. Retrieved from https://www.soundonsound.com/sound-advice/dynamic-range-loudness-war
Owsinski, B. [Author] (2013). Introducing Mastering [Video]. Retrieved from https://www.lynda.com/Pro-Tools-tutorials/Introducing-mastering/109358/120958-4.html