Mastering is the final stage of a recording project, where a song and its mix are already a cohesive whole. It’s also the final step before manufacturing begins, where mix problems such as sharp transients on snares, bad tones and inferior microphone selections can’t be adjusted. Everything affects everything else; for example trying to EQ a snare will affect the vocal, guitars and so on.
When preparing for mastering, it is wise to consider printing multiple versions, such as vocal up, vocal down, instrumental, full mix, radio edits and even stems as these can be useful in licensing situations down the road. In and out fades can be taken care of in the mastering stage as can edits such as clean versions or radio versions, without going back into the mix. The final step before sending your masterpiece off to be mastered is preparing the mixes and assuring file names and spelling are correct and everything is properly labeled, tagged and orderly.
Preparation
It’s time to launch a new session in the same format that the mix files are in, for example 24-bit 44.1Khz. The final processing will be possible in many software programs, for example those from SADiE, WaveBurner, BIAS Peak, Pro Tools, IK Mutimedia, and others. Your files are imported into the DAW and then it’s time to start thinking about “the album” as a whole, most importantly the song that stands out as the best production – the project model. This track will serve as the “master” of the masters and be the example that will be chased for the rest of the mastering process.
When starting the first master, a good rule of thumb is to have a commercial disc or equivalent of your envisioned project ready to A/B. Listening to the chosen album as a whole will provide the best overview of the “master.” At this stage it’s not about the individual instruments, fx or tones but more about sequencing – how the songs work together to create a cohesive whole. As you get your head around this overlooked practice, patience will pay off. Arranging the disc to maintain a level of interest from the listeners should be the Golden Rule. A wrong song choice can halt the momentum of the entire album, and kill all that time spent on mixing. The best route to avoid any confusion is communication to and from all levels of the project team.
EQ
Now that the files are imported into the DAW and the song sequence has been chosen, it’s time to get started. Most EQ’ing will happen on a broad level, but if parametric EQ is being employed, small steps will assure that the mix doesn’t slip over the edge and end up as an over EQ’d project. There are an overwhelming number of choices out there and wading through all of them can be challenging. A lot of EQs will model their designs on analog gear, which means they will have a “warm tone” and that they are more musical.
Linear phase EQs are made to create minimal phase shift, while engaging multiple filters at the points that they overlap. This should be used if the desired outcome is a “cleaner sound” with minimal coloration at the filter points. Some plug-ins come equipped with a “Look ahead” function, which will scan forward, looking at the audio file as it moves through the plug-in. This aids in smooth the operation of the plug-ins, since they are notorious CPU hogs.
The Squeeze
Mastering compression is a chance to improve the overall dynamics of the record. Taking into account the amount of compression that has been added during the tracking and mixing phases will help determine the feeling that is sought after with regards to compression. Software compressors have their own functionality in regards to how they handle the sound. Knowing the tools, their sound, and limits will speed up the process at this stage.
Compressor equations that are based on solid-state analog compressors will tend to have a bit more aggressive sound where tube emulations will have a little “smoother” sound and tend to round transients off. Using compression in small increments will prevent pumping. When calculating what settings to use for attack and release, look for the happy medium of preserving the natural punch and tone of the record, while taming and controlling the dynamics. Always keep an ear out for unwanted audible compression.
Limiting, another form of compression, will help the sound reach the desired loudness. This is a crucial step to consider in the mastering process and one the end user will most notice. In science, limiters will let anything below the threshold pass while compressing the peaks. The main difference between compressing and limiting is that limiters will use a very high compression ration 20:1 or higher. The output level should be very close to 0 dBFS, usually .1 dBFS or so should reassure no constant 0s, which can be undesirable when it comes to manufacturing.
A software plug-in meter will help to perceive each track’s level in relation to the other and will ensure that all are well balanced. This stage will require the utmost attention because any errors will be transferred with files. At this point, dithering should be considered, but will only be necessary when reducing the bit depth. Using dither as the final step will help with randomization of quantization errors.
Authoring
CD authoring will only be necessary if physical discs will be manufactured. If the project is staying in the digital world, then tagging will be a friend. CD Text is usually a preference that has to be turned on within the burning or mastering software. Making sure this option is checked will confirm that the ISRC codes, which are the tracking info for the songs, will be on the disc. ISRC codes are obtained by contacting the RIAA. If you don’t already have a UPC for your project, most manufactures will provide one as part of a “package” deal.
Final Tips
CD Mastering
When burning the disc there are a couple of options. “Disc at Once” will burn the CD without stopping the burning process, where as “Track at Once” will burn each file and stop the laser in between tracks. A DDP file is a disc image that contains the audio and all related files. A lot of programs won’t come with this, but it may be offered as an extra upgrade. If DDP is the choice then check with the CD manufacturer to make sure they’re setup to accept this format.
Remember, whether mastering in or out of the box, software is just another tool to get the job done. Trust your ears, and don’t expect the computer to do the job for you.