THE MASTER DEBATE

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

SPACE AND BASS

At this point in the chain of mastering processors, you may want to add that special something. If a mix needs some extra shine, stereo enhancement is a good way to go. But that needs to be applied carefully because it can have a negative effect to the sound quality if too much of it is applied, or it's applied incorrectly.

Logic Pro 7 includes an excellent native stereo enhancer that allows the stereo signal to be modified by splitting the signal into a number of bands and then distributed them at whatever intensity you want over the stereo field. A useful aspect of the plug-in is that you can choose at which frequency the enhancement begins. That means that in the crucial mastering stage of production, you can widen only the upper frequencies without affecting those all-important low-end instruments in the mix. If you don't use Logic, there are equally good native enhancers in other DAWs, such as Reason's M series of mastering processors. There are also third-party plug-ins that that will do the same job, such as Izotope Ozone and PSP StereoPack 1.8.

Another nice touch here can be psychoacoustic sub-bass treatment. That can add perceived bottom end without actually increasing the overall level of the signal. Some excellent plug-ins, such as Waves MaxxBass, can supply this effect. But use with caution and watch those serious low levels going into the final stage of the chain. If need be, use a simple highpass filter to cut anything below 30 Hz to ensure that you remain in control of the signal.

KNOW YOUR LIMITS

The final stage of the mastering chain should be a brickwall or peak limiter. That is similar to a limiter used in the mix process but with an absolute output level set by the user. These limiters usually have a threshold or input gain, allowing you to increase the signal flow into the processor. Usually, there is also a release control to tailor the limiting effect to your program material.

By driving the signal against this virtual brickwall, you increase the density of the audio and therefore the perceived loudness. That is achieved because the human ear reacts to average volume levels rather than peaks and troughs. There is a huge list of these limiters (often known as maximizers) out there, including Waves L2 and L3, Voxengo Elephant, Kjaerhus MPL-1 and Universal Audio Precision Limiter. Most DAWs also supply native mastering solutions with their packages.

Although this technology is widely available, there is a huge debate over whether we should be pushing volume levels into outer space. There is now a fierce “volume war” among commercial releases, and many people worry that that is robbing music of dynamics. As long as this form of limiting is used with some control, the end result can be an exciting and up-front final mix. It's up to you how far you push things. For a few sensible rules, try not to go over -3 dB of gain reduction, stay below -0.1 dB as a ceiling (to avoid digital clipping) and leave the track some room to breathe. Remember that if the level is completely maxed out, you're approaching what resembles noise.

TO DITHER OR NOT TO DITHER

Once all the processors have done their jobs, there is one final thing to consider. What bit depth is the production currently at? If the answer is 24 or 32 bits, then you need think about how to get this number to 16 so that they can be burned to CD or successfully converted to MP3.

Although the math involved here is complex, the actual process is easy; it's usually an option in the export process in a DAW or a simple native plug-in. Some mastering limiters include dithering options. Whichever method is used, it's essential that music is dithered only once during the mastering process (usually it's done at the very end, so the processors work at a full 24 or 32 bits). If you work with 16-bit projects, then you won't need to dither down.

The same thing goes for sampling rates. If you work at 96, 192 or any rate higher than 44.1 kHz, then you will need to get the project down to 44.1 kHz. This process should also be applied only once and should be done in a professional audio-editing application. If you are at all confused about these processes, contact a professional until you are more confident.

IF YOU GO PRO

You may not yet feel ready to tackle mastering yourself, in which case you should approach a professional to take care of the final stage. If you go down this route, it can be a good learning process, and most mastering engineers should be very helpful and discuss delivery methods and requirements with you.

When delivering your mix to the studio or engineer, make sure you are 100-percent happy with the levels and creative elements in your mix. Once you have submitted your material for mastering, most studios will charge you twice if you resubmit with mix changes. Also, as I mentioned before, go easy on the limiting and compression in your mix and leave plenty of headroom for the engineer. Ignoring that will only close doors for the mastering engineer and may not give you the best possible result.

If you don't know whom to hire, get some recommendations. There are now hundreds of mastering services around, and the best way to delve into this area would be to find a friend who has had good service. Because mastering engineers can charge anything from $60 to $600, make sure your chosen engineer is affordable according to your budget. However much you pay, if you are not happy with the end results, don't be afraid to say so. Most places will make alterations.

Whether you choose to tackle the job yourself or employ some professional help to get to your destination, I hope these tips and guidelines will help you on your way. If you have any questions, please feel free to e-mail me at info@virtualopenair.com.

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