THE MASTER DEBATE

Jul 1, 2007 12:00 PM, By Mo Volans

FEELING THE SQUEEZE

Compression is a very important part of sound sculpting and creating the perfect mix; likewise, compressors are an essential part of the mastering chain.

For many years, a large, expensive tube compressor was the weapon of choice. A Manley Slam or Avalon was a common sight in mastering suites. In many high-end studios, these pieces of hardware are still common, but don't let that deter you. Software emulations and DSP-based plug-ins have improved by leaps and bounds in recent years, and these imitations offer the budding producer a realistic option for professional results. My choice for software-based emulation is Universal Audio's excellent UAD-1 DSP system, offering loads of perfect reproductions such as the 1176LN, LA-2A and recently approved Neve emulations.

There are two forms of compression you can use in the mastering chain: bus compression and multiband compression.

Bus compressors are just the same as a stereo compressor you would use in the mix process, although some may have dedicated controls such as stepped increment ones for easy reproduction of settings. Also, they may have features such as highpass filters and program-dependent, automatic release and attack functions.

A standard high-quality software or emulated hardware stereo compressor can be used for bus compression. Very slow attack and release times tend to be used here, often with the lowest ratio setting; that ensures as little loss of dynamics and transients as possible. With the correct settings, 2 to 3 dB of gain reduction will give a transparent result and a nice, easy leveling of the entire mix.

At this point, if there are any noticeable peaks in your final mixdown, it is a good idea to lower them manually by selecting sections of the file in a quality audio editor (such as BIAS Peak for Mac or Steinberg Wavelab for Windows). Once you have chosen your culprit sections, you can apply some subtle gain reductions of 1 to 2 dB at a time. That can achieve good results and means that the mastering processors will be working more consistently and are therefore more transparent in their treatment.

Multiband compressors are extremely useful for problem solving. Precise surgical control over dynamics is possible anywhere in the frequency spectrum using multiband compressors. For instance, with a 4-band processor, the amount of compression could be intensified in the subregion (30 to 80 Hz) to reduce a boomy kick drum or bass guitar without affecting the 100 Hz thump in the rest of the drum and bass parts. High-frequency parts can be controlled without losing the dynamics of the original performance or sample. These plug-ins go into areas that standard equalizers cannot reach.

Although presets in mastering are generally a bad idea, if you are new to these processors, presets may be a good starting point to at least see the separate bands working. If you are mastering your own material, and there are serious mix issues you are trying to fix, it may be best to go back to the mixing process to rectify things.

Companies such as Waves, Izotope, Universal Audio and Roger Nichols Digital have gone to great lengths to produce some excellent dedicated mastering plug-ins in this area. These processors used to be available only in dedicated (and expensive) hardware units, but now they are at least affordable and in reach of all musicians.

SATURATED PHAT

A common complaint about modern digital systems is that they sound too clinical and cold. That's because modern 24- and 32-bit systems are so accurate. There's a romantic notion that analog tape-based recording systems sound warmer and fatter, and these qualities are actually due to noise and harmonics introduced by saturation. Having a huge Studer or Ampex tape machine in your studio to bounce tracks back and forth to is unrealistic. Thankfully, these tape or saturation characteristics can now be attained with the use of plug-ins. PSP VintageWarmer 2 is a great tool for just this purpose.

When using those kinds of processors over an entire mix, proceed with caution because too much can lead to distortion, and it's easy to over-color the sound. These effects may be pushed much harder when used on separate tracks at mix level, but when used at the right level on a master, they can add that special something that can make a good track great.

There are other good plug-ins for saturating mixes, such as Antares Tube (now discontinued). That emulates tube saturation rather than tapelike effects, but it is still great for mastering when used at the right level. Also, some bus compressors, such as the Universal Audio Fairchild 670 emulation, have a drive input that can reproduce excellent and usable saturation effects.

THE END OF EQ AS WE KNOW IT

Everyone knows how valuable a tool EQ can be, but the way it's used in mastering may be surprising. When using EQ at mix level on an instrument or track, some of the tweaks and adjustments can be quite extreme (especially if used as a creative effect). As long as what you're doing sits in the mix and really adds to the production, there's no limit to your imagination. But when it comes to EQ in the mastering chain, subtlety is key.

You may be used to adding 4 or 5 dB of EQ in your mix and using high Q settings to shape your sounds. In mastering, you have to use high Q values, changing frequency over large areas of the EQ. In doing so, you achieve much more transparent results and are less likely to color the mix. Again, it's wise to add only small amounts of EQ here; anything more than 2 or 3 dB may indicate an inherent problem at mix level. If you are mastering your own mix, you can fix the problem by stepping back a level. This is another area where it's apparent that good mixing techniques will lead to the mastering process enhancing and polishing the production rather than it being a troubleshooting process.

When it comes to choosing which EQ to use for mastering, it's really all about quality and transparency. There are many processors that are especially built for mastering; Avalon and Manley manufacture units essential to the pro mastering engineer. But as with compressors, a lot of high-end units are now easily affordable in software form due to hardware emulation. Some superb examples of those are the EQs in the Focusrite Liquid Mix (including the much-coveted Manley Massive Passive) and the Universal Audio UAD-1 system. Universal Audio also has its own nonemulation mastering range of plug-ins for the UAD-1 card, including an EQ, multiband compressor and precision limiter.

If you don't own either of these DSP systems and operate completely on native CPU power, there are other plug-ins capable of providing excellent results. The best option is a linear phase EQ. Without going into too much science, these plug-ins use processor-intensive algorithms to produce an extremely transparent and clean signal. However, you will use only one instance on the master bus, so CPU load shouldn't be too much of a worry. Waves Linear Phase EQ is excellent, and even some DAWs, such as Apple Logic Pro, now include linear phase EQs.

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