Reason Tutorials

I’ve found that one of the lesser understood bits of production and mixing in general is the whole issue of compression. What it does, when to use it, when to leave it alone. In this short tutorial I’ll cover the basics of what each of the parameters of the MClass compressor in reason do and give some examples of settings for different types of compression.

In actuality there are 3 devices in reason which can be used for compression/limiting the MClass Compressor the COMP-01 compressor and the MClass Maximiser. In this tutorial we’ll be using the MClass Compressor as its the most versatile and most generally useful of the 3. It can be used for a wide variety of effects from subtle loudness increases to hard and unnatural sounding side chain pumping effects.

M Class Compressor - Click for Close up

Parameters of the MClass Compressor and what they do

First a quick explanation of what each of the front panel controls actually do.

Input gain: A +/-12dB input level adjuster.

Threshold: Sets the level at which compression will actually start to occur. When the loudness of a signal is below the threshold level then the signal is left unaffected. Any signal above the threshold level is pulled down by an amount determined by the compression ratio. What this tends to mean in reality is that the lower the threshold is set the more obvious the compression will be.

Ratio: This control sets the amount of compression to be applied to the signal above the threshold level it can be set form 1:1 (no effect at all) to infinity:1. For example with a 4:1 compression ratio, if the input increases by 8dB, the output increases by only 2dB. Most practical day to day uses set this somewhere between 2:1 and 10:1

Soft Knee: When engaged this make the compression effcet come in more subtly and thus makes the effect more natural. This is of course not always what you want in modern dance styles or electronica.

Sidechain Solo: Allows you to hear an isolated version of the signal being input through the back panel side chain input.

Attack: Determines how quickly the compression effect is applied to a signal that goes over the threshold. A low value makes the effect come in quickly, a higher value brings the effcet in more slowly. This is useful for stopping the compressor from quietening the hard front edge of snares, high hats, etc.

Release: This determines how long compression is left applied after a signal drops down below the threshold. Lower settings will tend to sound less natural and “Pump” more. Higher settings tend to be used for more natural sounding compression.

Adapt Release: When set this automatically increases the length of the compressors release time for signals with longer peaks.

Output Gain: This is a final make up gain control to allow the final compressed signal to be made up to a level that will fit with the rest of the mix if compression has significantly lowered the overall level of a signal.

SC Solo, Attack, Release, Output Gain

General Settings for Drums

You have to listen to how aggressive the initial transient (or click/impact) at the start of the drum hit is and then lower its volume to be closer to the rest of the drum hits volume level. The more aggressive the initial hit the more less time you should give it before bringing in the compressor. Essentially you want to lower the initial impact which is much heavier than the rest of the hit and then use the make up gain to make the overall level of the drum sound louder throughout the drum hit.

Kick – Ratio: 3:1 Attack: 4ms, Release: 45ms. Soft Knee off. Adjust input gain, Threshold level and output gain to suit.

Snare – Ratio: 4:1 Attack: 4ms or less dependant on how aggressive the initial hit of the original sound is, Release: 45ms. Soft Knee off. Adjust input gain, Threshold level and output gain to suit.

General Settings for Other sounds

Vocals – Ratio: From 3:1 to 8:1 dependant on loudness, Attack: 50ms, Release: 100ms, Soft Knee On. Adjust input gain, Threshold level and output gain to suit. This is simply to take the top peaks off the vocal track so the vocals overall level can be mixed up without clipping and so sit nice and up front in the mix.

Acoustic Guitar - Ratio: 5:1 – 10:1, Attack: 5-10 ms Decay: 0.5secs. Soft Knee may be on or off dependant on playing style.

Electric Guitar – ratio 8:1 – 10:1, Attack: 5ms, Decay: 0.5 secs. Soft Knee off.

Bass – Ratio: 4:1 – 12:1, Attack: 1-10ms, Decay 05 secs. Soft Knee off.

Overall Mix Compression – Ratio: 2:1 – 6:1, Attack: 1-5ms, Decay 0.3-0.4 Seconds. Soft Knee on.

Sidechain Compression

Side chain compression is where an external signal is used to trigger the on off of the compressor rather than the threshold level. It is commonly used for House and Dance music “pumping” kick drum effects where the overall level of the general mix is pulled back while letting the Kick drum through at its normal level. We will this use in a future tutorial.

EQ before or after compression?

One question that is asked a lot is “should I EQ before or after compression”. The general consensus seems to be that you should EQ before compression in order to have a more predictable and controllable output volume of a sound in your mix. But (there’s always a but) this is not a written in stone hard rule. In some more experimental cases you can EQ after but the results tend to be less predictable.