All mastering techniques aside, mastering has gotten rather complex in the last 10 to 15 years when it comes to outputting final master files for all potential release formats.
In the 90’s, vinyl and cassette sales were nearly non-existent compared to previous and future decades (who would have guessed?), and the Internet was far too primitive to be considered a means of professional or legitimate music distribution. This meant that the mastering engineer’s primary focus in the 90’s was the compact disc, and pretty much only the compact disc.
Back in the day, there was a clear divide between a recording/mixing studio and a dedicated mastering studio. When the loudness war was in its early stages, you pretty much had to use a dedicated mastering engineer to avoid having a weak and quiet sounding master compared to professionally mastered albums. The tools needed to enter the loudness war (and most mastering tools in general) were not easily accessible or practical for a recording/mix engineer to own in most cases.
These days, it’s extremely easy to obtain the tools needed to create your own masters if you have the confidence, knowledge, and skills, using nothing more than a computer and the right plugins/software. I don’t necessarily advise it, but it’s certainly possible, which is pretty remarkable when you think about how things were 20 years ago.
People were still making vinyl in the 90’s but since the loudness war wasn’t too extreme for the majority of the 90’s, a lot of compact disc masters translated well enough to vinyl to call it good. I think the digital loudness war prompted mastering engineers to make special vinyl pre-masters because loud digital masters are usually far too loud to be considered “vinyl friendly”. I’ll explain that in more depth later in this article.
Napster and other peer-to-peer file sharing services popped up around 1999, but nobody was considering Napster’s technical limitations when mastering an album. Internet bandwidth was still a major limitation for uploading and downloading larger files. I believe that’s why the bar was set so low for compressed/lossy file formats to begin with. These days, most broadband and even LTE cellular data connections can comfortably stream 320kbps audio, and downloading full WAV files of an album is generally a quick process. Many Internet providers in the US still tend to skew upload speeds to be noticeably slower than download speeds though which is annoying for those that do more uploading than downloading.
In 2003 the iTunes Store launched, but again, mastering for compact disc was the mastering engineer’s primary focus, and digital distribution was more of an afterthought. It’s hard to say when, but sometime around 2009 I started noticing people caring specifically about the master files that were submitted for online distribution, and how they might differ from the “normal” CD master. I think what expedited this is when people largely stopped actually listening to CDs and merely imported the CD into their iTunes library and never again touched the actual CD.
In recent years, mastering for digital distribution has been broken down even more, as you can optimize master files for each retailer if you really want to get technical. Unfortunately, as it sits now, the same master WAV file you submit to CD Baby/Tunecare/Orchard etc. will be used for the standard iTunes release (not to be confused with Mastered For iTunes), Amazon, Google Play, Spotify and all others so you really have to pick your battles about how to optimize your masters.