Noise gates and noise suppressors help you getting rid of unwanted noises but in different ways: a gate basically works and stop sounds as soon as you stop playing (during “silence times”), while a suppressor works both while playing and when you stop picking.
It’s important for musicians, recording engineers and producers to understand that they have different purposes and should not be used interchangeably: noise gates are great at getting rid of unwanted background noise but not so good at preserving sound quality, while a noise suppressor has less impact on overall sound quality.
Despite this short and general answer, let’s see how they actually work and the benefits of each one (and also when you should use one type of pedal or the other one).
HOW DOES SUPPRESSORS AND GATES FILTER SOUNDS
A noise gate is designed to stop the signal from passing through when the input level is below a certain threshold: this threshold can be set manually or automatically, and is often used to eliminate unwanted noise from an audio signal.
A noise suppressor is designed to reduce the level of noise without removing it entirely, while still preserving the sound of the original signal: it achieves this by reducing both desired and undesired signals in proportion to their levels, rather than completely removing one or the other.
WHY ARE THOSE PEDALS USEFUL?
Both of those kind of utility pedals can be really useful if you usually play in high-gain settings, where feedback and background noises can be a serious problem during gigs and in general an annoying thing while playing.
This unwanted noises is here because circuits, cables and in general the hardware of your setup alter the electricity (the signal coming from your electric guitar basically) and therefore can generate collateral sounds on the way to the amplifier.
So, these 2 tools works by trying to cut out the frequencies of that annoyance, giving you a cleaner sound and overall a better sound.
WHAT TO CHOOSE FOR YOUR OWN PLAYING?
Both of these works for cutting out that nasty noise, so as lots of other sound-related questions the answer is the usual: it depends.
Both have their benefits, but their different behaviour can change a lot in their usability.
You can see some differences in the image below:
More specifically, a noise gate:
- let you achieve a silence/complete silence by blocking the sound as soon as you stop playing (the speed of that sudden silencing can be usually customised using the knobs, but using this you know that the sound will completely stop at some point);
- doesn’t work when you play, so it won’t alter the volume or sound during when you pick the notes;
- can alter the overall tone because of its more “aggressive” filter
On the other hand, a noise suppressor:
- Filter the sound in a smoother way, reducing the frequencies but not by blocking them, but rather by speeding the decaying of the sound;
- works both while playing and during silences;
- It doesn’t alter the tone in a very noticeable way;
- it’s usually way more customisable
SO, HOW TO CHOOSE BETWEEN ONE OF THESE?
Actually both of those are great in their own duty, but in general a noise gate can be used for dramatic silences during your playing (for example in high-gain music, for example metal and in particular subgenres such as djent, where you need a total silence as soon as you stop playing).
On the other hand, a suppressor is better for smoother sounds and the high flexibility and customisation can be more or less good for almost everything, also considering that it doesn’t alter your tone as much as the noise gates.
Choosing based only on written text can be quite difficult for a sound thing like that, so you can listen to some demos here: