The art of mastering is shrouded in mystery. Although it has always been an essential part of the creative process, mastering is often misunderstood — largely due to the fact that the role of the mastering engineer has changed so much over the years.

Originally, mastering engineers were only responsible for transferring recordings from one format to another, typically from tape to vinyl. With the advent of digital recording and processing technology, the role of the mastering engineer shifted to include making the final creative decisions before a record is released.

In this blog, we’ll break down the role of the mastering engineer, how it’s changed over the years, and why it’s more important than ever to have your tracks mastered on a well-tuned monitor system.

The History of Mastering

In the early days of recording, there were no specialized roles—a single engineer oversaw the entire process from start to finish. Early mono recordings were typically created by simply placing a single microphone in front of a live band. Audio was cut directly into a wax or acetate disc, which was then used to create a stamper for 10-inch shellac or vinyl records that played at 78 RPM.

It wasn’t until Ampex produced the Model 200 tape recorder in 1948 that the need for a dedicated “transfer engineer” became necessary. Transfer engineers became experts at transferring recordings from tape to a vinyl master for reproduction.

At first, each record company or transfer engineer applied its own equalization to optimize the transfer of tape to vinyl, but in 1954, the Recording Industry Association of America introduced the RIAA equalization curve as the de facto global industry standard for vinyl records. By standardizing the frequency response of playback devices, records could be cut with narrower, tighter grooves, allowing for longer playing times. Bass-heavy recordings presented problems with the stylus jumping out of the groove and potentially damaging the records, so engineers began to apply corrective EQ, which further optimized their ability to create more playable, better sounding vinyl records.

This was the beginning of modern mastering — when the role of the mastering engineer shifted from a purely technical process to a creative one. It was during this era that engineers like Steve Hoffman made a name for themselves by enhancing masters with creative tools like EQ and compression. Hoffman was known for his work in jazz artists including Miles Davis, Ella Fitzgerald and The Beach Boys.

Stereophonic Sound

In 1968, Sterling Sound became the first studio in the US to cut stereo discs, which opened up a whole new creative world for transfer engineers, as they learned to affect stereo width, frequency balance, and dynamics. These engineers became responsible for not only transferring audio recordings from one format to another, but also for improving fidelity in the process. As engineers made more and more creative decisions, the term “transfer engineer” eventually gave way to “mastering engineer.”

Bob Ludwig, one of the most well known mastering engineers, began his career during this era. Ludwig has worked on projects by more than 1,300 artists, resulting in over 3,000 credits, more than 25 Grammy nominations, and is known for his work with The Rolling Stones, Queen, Sam Cooke, Nirvana, and Coldplay. He has mastered recordings on every major analog and digital recording format and has provided services for every major record label. He operates out of his own facility, Gateway Mastering, in Portland, Maine.

Going Digital

When CDs were introduced in 1982, the audio industry underwent one of the largest disruptions we’ve ever seen: the adoption of digital audio. Along with the advent of digital audio, the 1980s ushered in numerous advances in sound technology, which advanced the mastering engineer’s role even further.

Along with hardware based digital recorders from AMS, Waveframe, Fairlight and New England Digital, computers like the Apple II, Atari ST and the Commodore Amiga were becoming powerful enough to handle digital audio processing, paving the way for the modern DAW. Avid (formerly Digidesign) created the industry-standard Pro Tools software, which started out as a simple audio editor called “Sound Designer” and was primarily used to edit samples for keyboards like the E-mu Emulator II and the Akai S900. Sound Designer was eventually bundled with Mac-compatible interfaces as Sound Tools.

Digital audio formats offer improved dynamic range and provide a greater signal-to-noise ratio over analog formats, and allow mastering engineers to increase the perceived loudness of a track. As soon as artists discovered that listeners (and radio programmers) think a louder version of a track sounds better, they began requesting louder and louder masters — often times at the expense of musicality, dynamics and, of course, distortion.

For years, the battle for the loudest record has raged on through what is now referred to as “The Loudness Wars.” Today, more than ever, the Loudness Wars negatively affect the way music is enjoyed, especially on streaming services which automatically match song-to-song volume levels without any dynamic processing.

The Loudness Wars

While the competitive practice of pressing loud records has been around since the 1950s, Greg Milner, a music and technology journalist, identifies 1994 as the year in which “there was no turning back” for the Loudness Wars. By 1999 it had gotten so bad that many of the top-selling albums had almost no dynamics, leading some engineers to call it “the year of the square wave.”

Modern records, on average, are about 18 dB louder than in 1980. Digital recording allows for peak limiting which makes the “target” of 0 dB easier to achieve, but it also makes it easier to increase the average loudness which, in effect, smashes the life out of a record.

In honor of Dynamic Range Day, a day created to bring awareness to the Loudness Wars, mastering engineer Ian Shepherd charted the average loudness of some of the most popular records from the last 20 years. Shepherd found that Metallica’s Death Magnetic (2009) is the loudest album ever created, with an average dynamic range of just 3dB (from peak to RMS). For reference, Metallica’s The Black Album (1991) has a dynamic range of 11dB.

While average RMS levels have dropped since 2009, the Loudness Wars still wage on to this day.

Modern Mastering

Over the years, mastering has evolved into an entirely new craft. Once tasked with transferring recordings from one medium to another, mastering engineers are now responsible for creatively adjusting frequency response, dynamics, RMS levels, stereo width and more.

Modern artists and producers can record, mix and master their own tracks right from the comfort of their own bedroom. However, since mastering is the final phase of production and the last chance to affect the final product, the most important role of the modern mastering engineer is to ensure your tracks translate well to any system. With computer-based mastering, everyone has access to fantastic tools to shape and enhance the final master so it is increasingly important that even the bedroom studio has a monitor system that can be trusted to accurately reproduce music. The only way to know what your music will sound like on other systems is to trust the accuracy of your own monitor system.

Sonarworks Reference software ensures that your monitors and headphones are as accurate as they can be. For more information on how Sonarworks can help you master your music, click here.