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Compression

 

The Basics

 

 

Lets go into details on all the features and knobs on the compressor.

First lets look at attack and release.

 

Both the attack and release knobs control how the the compressor reacts.

They deal with how fast and how long the effect will last.

 

The attack deals with how fast the effect will take place.

The release deals with how long the effect lasts.

 

 

 

 

On both the attack and release you will see numbers.(often 1-10 or 1-100)

 

On the attack, the lower the numbers are the faster the effect takes place.

 

On the release the smaller the number is the faster the release time is.

 

Don't expect the attack and release to be used with similar settings.

 

This is often not the case.

 

Often you will want to start with a fairly fast attack because you will want the compressor to kick in quickly so that not to many transients will peak out before the compressor starts.

 

The release can often initially be set at about 40% for a starting point.

 

What you want to achieve here is density with out deadening the musical track.

 

 


Let me explain:

 

One of the ways a compressor works is by narrowing the musical dynamics.

 

It does this by bringing up the quiet passages and bring down the peaks.

The result is a more fat or dense track.

 

The way the attack and release relate to this when the attack is set fairly fast, the compression kicks in and tightens the dynamics as they occur.

 

Think in the case of a snare drum...

 

The snare drum is hit and decays fairly fast.

 

If your release setting is to slow the compressor will not have the chance to reset itself.

The end result will be all the snare hits will have very similar dynamics.

 


 

This can make the snare seem dull.

 

So with a snare drum you will want the release to be fairly quick.

Of course the attack will have to be set to the fastest setting as a snare drum naturally has a very fast attack.

 

Lets say we are recording a clean electric guitar.

Again lets set the attack fast but not as fast as the snare.

 

We will use a slightly slower attack time so we get a mild sloping to occur.

 

This can sometimes give an instrument a nice controlled dynamic.

Now for the release time we will set it at about 55-60%.

 

This will create a nice dense signal on the guitar making it sound fatter and fuller.

You can adjust the release time until the track sounds denser but not dull.

 

You will need to use your ears for this because these settings of course will vary based on the tempo, dynamics and how the instrument is played.

 


 

The next parameter we will look at is the

Threshold.

 

Threshold

 

The Threshold knob will control at what level the signal will become compressed.

 

Unlike many effect units the amount of effect is expressed in -db or negative amounts.

This means the more you turn the knob down the more effect you will get.

 

Because compression is designed to control dynamics this makes complete sense.

When we lower the threshold we dip the starting point to sense musical peaks deeper down into the musical dynamics.

 

The lower the threshold, the more the peaks and signal trigger the compression.

Don't worry its very simple.

 

The lower the threshold the more compression will be used. 

 

If you were to turn down the threshold all the way you would be compressing the entire signal.

(and boy how dull that would sound)

 

 

 

 

Next lets look at:

Ratio

 

The ratio control of much the signal will be compressed after it passes thew the threshold amount.

 

These numbers most of the time are expressed in terms of n:1 ratio.

 

Here is what this means:

 

If you use a ratio of 3:1 then for every 3 DB over the threshold the signal will peak by only 1 DB in the effected signal.When working with ratio settings start small.

 

Start with an initial setting of 1:2 and slowing turn up the ratio.

 

1:3 or 1:4 are common ratios settings.

 

When your ratio is up toward 1:7 then you are using a limiter.

The main difference between a compressor and limiter is simply the amount of ratio.

Adjustments

Some compressors have a auto gain feature.

What this does is automatically adjust the output volume

of the compressors.

 

Often if you have added a good amount of compression with a high ratio you may have to adjust for a lower output by turning up the volume.

Some units do this automatically other do not.

 

Always be careful to not bring your output up to high as this can cause distortion.

Compressors are very important tools that can improve the quality of your recordings considerably.

 

They can also help to make your recordings work on a number of different playbacks systems better.