Tools Mastering Engineers Choose

Mastering engineers use tools that are similar in function to what we use every day in the studio, but with some significant differences. Mostly, these lie in the realm of the precision and accuracy (and therefore repeatability) of their performance. Further, mastering tools tend to be very high in resolution, so that the mastering engineer can effectively work at resolutions greater than 16 bits and then satisfactorily reduce the resolution of the master tapes to the release medium of 16 bits, assuming that the source tapes also have greater resolution than that. Incidentally, some mastering engineers prefer to work in analog during some or all of the pre-mastering process. It’s a matter of personal taste and preference.

Equalization

Equalizers of choice are parametrics, with extremely precise settings and matching between channels. In addition, widely adjustable shelving EQs and high and low frequency cut filters to work on the ends of the audio spectrum are also used. Notching filters are used for problem-solving. The EQ on board the Sonic Solutions workstation is chosen by many, and one current hot number is Daniel Weiss’s new outboard digital EQ. Numerous engineers stick with analog (Neve is a popular brand), and much customization goes on to suit the preferences of the individual engineer.

Compression

Compressors are a key tool used in mastering. The very precise, sometimes stringent, need for levels management, coupled with the desire to make such management as “inaudible” as possible, makes the use of compressors very tricky and extraordinarily important. One successful mastering engineer has allowed to me that it took him more than two years of working as an apprentice in a mastering facility before he was able to really “hear out” compression.

Often, there are profoundly different needs for different sections of a recording or for different components of a mix. Again, precision and reproducibility are key features of compressors. Split spectral bands to compress separately are a very useful feature, along with comparatively complex transfer function curves (an extension of the so-called “over-easy” type of function). The key element in any compressor is its level detector (envelope follower, to some of you), and the sonic effect of this circuit in all of its settings is of key importance to mastering engineers. Finally, because mastering engineers work on finished stereo mixes, it is necessary for them to have good control over the signal sent to the two level detectors.

Favorite compressors include units from Neve, Junger, NTP, SSL, Focusrite Blue and TC Electronics. Note that none of these are normally used in studio production work, because of their specialized nature.

Reverberation

Reverberation is very hard to remove from recordings without really affecting the sonic quality. For this reason, reverb is usually fixed at the time of mixing, although occasionally additional reverb may be added during mastering, for enhanced consistency and smoothness in transition from one track to another. Beyond that, reverb is not a significant element in the mastering process.

Editors

Much mastering is done in the digital realm, although many engineers still prefer analog. Because assembly editing – and sometimes music editing that cuts between multiple mixes of a song – has become such a feature of the mastering process, the use of a Digital Audio Workstation (DAW) is extremely helpful. The workstations of choice seem to be Sonic Solutions (Mac), and SADiE (PC). While much of the editing is comparatively easy, the workstation is also the place where we concern ourselves with data management, including truncation or re-dithering, the use of high-quality converters (for analog masters), normalization and general levels management, as well as the placement of track IDs (P and Q codes). This includes cross-fades, hidden tracks, and other cheap tricks. Digital converters are chosen by each mastering engineer for taste and preference, and are usually available at the 24-bit level.

Stereo Management

It often falls to the mastering engineer to get the stereo impact of the recording to be consistent from track to track, as well as sometimes to either enhance it or reduce it. This is generally done with a shuffler, but there are a variety of other “spatial” devices that are often employed at the mastering stage to enlarge or enhance the “stereo soundfield.”

Look What They’ve Done To My Song(s), Ma

In preparation for CD release, mastering engineers assemble the supplied mixes into a desired sequence, fix the level of each song, establish the EQ and compression that will be used (including changing it where needed), fiddle with the stereo, fix the bits, re-dither as needed, and then create the master tape into one of several formats used to make CDs. The order in which this is all done varies greatly according to individual preference and working habits.