Bass Guitar Effects – Compressors, Limiters and Noise Gates

February 20, 2010 | By Vikki Alexander In Accessories, Effects Pedals |

In this article we take a look at what are not really bass guitar effects, but units that help control your volume. More accurately called dynamic controllers they control the volume under various playing conditions. We will discuss three types of dynamic controllers: compressors, limiters and noise gates.

Compressor

A compressor, as the name suggests, compresses the signal. This evens out the volume by preventing the loud signals from getting too loud. Compression is especially useful for bass guitar where the lower notes can often be much louder that the higher ones. You will find it almost essential if your playing techniques include slapping or popping the strings.

Some of the controls found on a typical compressor are:

Threshold
This is the point where volume control begins to happen. Any input signal below this level will pass through the unit unchanged, but higher input levels will be controlled according to the ratio setting.

Ratio
This is the amount of volume control that is applied to the input signal after the threshold has been reached. The ratio is expressed as a:b, where a represents the input signal level b represents the output signal. For instance a ratio of 2:1 means that for every 2 dB (decibels or units of sound) of input signal that exceeds the threshold, only 1dB of increase will be output. A mild compression ratio would be between 2:1 and 4:1 and anything over 8:1 would be considered severe. Using a very severe a compression ration will make your sound very flat and lifeless.

Attack Time
If present, this will control the length of time between the moment the input signal exceeds the threshold and the point where compression begins.

Release Time
This is the opposite of Attack time and controls the amount of time between when the input signal drops below the threshold and the point at which compression stops. Not all compressors will have this control.

Limiter

Limiters are a very aggressive form of compressor that use a very high ratio. Once the threshold is reached no further volume increase will pass through. Limiters are useful to prevent sudden volume spikes from damaging sensitive equipment such a speakers.

Noise Gate

Using effects pedals can sometimes result in unwanted noise which may be consist of a hissing or buzzing sound, noticeable when you are not playing. A noise gate will remove any signal below a certain threshold, removing the noise. If the threshold is set too high, you may find that you are removing some of your playing as well.

In summary, a compressor or limiter used carefully is a very useful piece of equipment that will help smooth out your sound and make it more polished. You will probably not need a noise gate unless you are using other bass guitar effects at high levels such as distortion or fuzz.

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