Compressing in "Stages"
Stage 1: Adding Control Compression
The purpose of this compression stage is to control any sudden high-level peak that could cause the average level to be brought lower. This compression has much the same effect as "tape compression" in analog recording, and can be omitted if the mix was originally recorded on analog tape.
We need somewhat of a soft knee compressor will be used with a compression ratio moving towards limiting (5:1 to 9:1). Attack time should be fast (1 - 2 ms.) and the release time medium-fast (40 - 50 ms.). When we set the threshold so that gain reduction peaks to -3, so that it effects only the loudest peaks. Makeup gain can be set to restore level after compression (at least 2.0 dB). For mixes that have uncontrolled peaks, the higher ratios (8 or 9 to 1) should be used; slightly higher gain reduction could be allowed on these peaks, as long as there usually is no more than 3 dB reduction.
Stage 2: Adding Mild Compression
A mild amount of compression will give us general increase in apparent volume with very little objectionable effect on the dynamics of the tune. Done properly, the mix will often have twice the apparent level, especially in a mix that has a lot of musical dynamics.
When we say mild, we mean both a low compression ratio (between 1.5:1 and 2.0:1) and mild amount of gain reduction (6 dB). The attack time should be fast, but not at 0 (one or two milliseconds so that the compressor begins to compress right after any transient attack begins. We will be adding additional dynamics processing to control the initial peak of a transient, which is usually formed in the first 2 ms. The release time should be medium (100 ms. range) or a variable-release can be used.
We will be using a plug-in made by T.C. Electronic** called MasterX.** The compression and dynamic processing in this plug-in is done in three separate bands. The bass, midrange, and treble ranges are split, compressed separately, and re-combined back into one signal. With this kind of arrangement will prevent most compression pumping problems and make it much harder to hear the compressor working. .
The plug-in will automatically apply makeup gain after the gain reduction so that the original peak level is attained after compression. As you move the threshold slider down you will hear an increase in the volume of the lower-level passages and instruments, plus an increase in the apparent level of the mix.
Stage 3: Adding The Final Loud Edge
Final increases to the apparent level will occur by applying limiting to control transient peaks. We will often use a Waves** program called L1 Ultra-maximizer to accomplish this task. In previous compression stages we only controlled peaks after 2 ms. With the maximizer the attack time will set to "0" ms, and the release time at the ultra-fast setting of 1.0 ms. With these time parameter settings, the transient peaks will be literally sheared off. If you do not have a Waves Maximizer, use a fast-acting limiter and adjust the attack/release times according to the above times.
Care must be exercised in applying this limiting. Since it is literally clipping the signal, there is perceptible distortion being added. A little bit can cause a nice "edge" to the mix and too much causes it to sound dirty. The changing gain-reduction metering is fast-acting, making it hard to read the amount of gain reduction being applied. Fortunately, there is a maximum gain reduction figure (in dB ) that is displayed below the metering. It is a good idea to set the threshold for 5 dB or less gain reduction at this stage, although the ears should be your guide.
Don't expect to become an expert in one lesson. Carefully following these guidelines, however, should greatly improve your final sound.
Specifically, I am curious about attacks. Is a 1-2 ms attack the standard for average, modern music mastering purposes (where 2 would be a relatively slow attack and 1 would be relatively fast)? It seems a bit quick to me ...
What average range do you tend to work within?
Are there any constructive comments or suggestions to add on other points?
So far that passage has been the best resource I've come across for how, in general, to practically compress/limit music.