Audio compression

Secrets of the Master CD - Mastering Audio Compression

One of the processes most important for a good sonic result is the compression. Many already know that compression can be achieved very rich sound and is one of the most versatile and useful in a recording. There are so many applications that can give this, which also can be turned into our worst enemy, if you do not know enough.

However, there are two purposes of a mastering compressor.

• reduce the dynamic range for more power output noise level, and
• offset this loss by giving certain "punch" to the mix.

Not all styles of music can be compressed in the same way, since reducing the dynamic range in classical music for example, would be almost a crime. On the other hand, there are styles like techno, or heavy metal that will be benefited with compression.

There are many opinions about whether to use compression, but the trends of the times require us to sound as loud as possible. So we reconcile compression criteria and use effectively. Without hurting anyone's feelings.

First we must consider that all parameters depend absolutely on our entry level. We can not just talk about a specific value of "Threshold". If you speak rather of amount of reduction in decibels.

For blended with rich harmonic parameters should think to compress at a rate of 1:1.5 with a slower attack of 150. Ms and an even slower Release of 1500 Ms.

The reduced decibel levels should not exceed 3 dB, as we will have such a loss of dynamics that they have little moments of loudness, we come up forces minus the return of the full sound.

If we wish to obtain Punch, then we must think of a compression ratio of 1:2.5 with a fast 5 ms Attack and fast Release also about 100 Ms, to be set according to the chronological distance that exists between blow and blow, so that the compressor has stopped working just before the next stroke. (Snare or Kick).

On the other hand we have the Multiband Compressor, which derive from the old method of compressing by Side Chain.

These compressors other than to achieve the aforementioned effects, for different bandwidths that establish, also have other applications such as for example, the de-esser.

With this type of compression can be achieved more control finish mixture, being usually be from 4 bands. The cutoff frequency between band and band will depend on what we want or need to do. But in the end will address the low frequencies, with Releases and Attacks slow unless we want the strong kick drum, where we have to reduce these values. And as we go up in frequency, gradually reduce the values ​​of these parameters. This is due exclusively to Lambda or duration of a cycle of a certain frequency. That as this goes, this is shorter. Clarify that these compressors do not handle the full dynamic, if not for each frequency separately.

With compressors or multiband dynamics processor alters the loudness of music, by means of the compression ratio between each. Therefore our first aim will be to achieve a flat frequency response, or as flat as possible. To this we must constantly check what we are hearing with a spectrum analyzer. Once this is achieved we can compensate for any loss monitoring deficiency in the mix, and even coloring in some way the end result.

The PlugIns are recommended TC Electronic, Wave and C4, where they can start with the parameters set by the manufacturer, who are usually very good, varying them and go according to our requirements.

* Articles written for our Forum .