Noise. Every musician, audio engineer or live sound mixer is familiar with it. That horrible, unwanted and mood-destroying hiss or screech that always seems to happen at the worst possible times. It can be present as high-pitched, nasal and mid-ranged, low and humming or via a heap of other ways.

What we mean when we say “noise” is almost always in relation to something undesirable. We don’t mean the experimental musical style, also called “noise”. Some of that stuff is great. Noise in this instance is the audio we can hear that we don’t want in our overall sound.


Noise in the guitar world is usually the result of electromagnetic interference (EMI) which is all around us in the modern world. This EMI interacts with many guitar cables, pickups, amplifiers and other electronic equipment and when fed into a guitar amplifier (particularly amps with high preamp gain), can produce a lot of unwanted noise.

Sometimes noise can even stem from maintenance issues such as cables, dirty pots and jacks on pedals and other gear, damaged amplifiers, poorly wound and installed pickups or other guitar electronics to name but a few common causes.

As every player and their setup is different, noise can come from many different sources. The best way to avoid noise is to use quality equipment, look after it and have it serviced. But that’s often easier said than done. Simply put, you know when noise is present and you definitely want it gone.

Many guitar players who play at high volume with high gain find themselves in an ongoing battle with noise, hum or unwelcome feedback. The solution is to incorporate some sort of tool to defeat the interference. For many players, that solution is the BOSS NS-2 Noise Suppressor.

Contributed by Byron Struck and Matt Walsham for the Roland Australia Blog


In continuous production since 1987, the BOSS NS-2 is a best-selling staple of BOSS pedals. Used by everyone from bedroom players to international touring bands like Metallica, Slipknot, U2 and The Dillinger Escape Plan among many others, the BOSS NS-2 is an industry standard in noise suppression.


Its innovative design is as effective today as it was at the time of its release. Whether you are looking to minimise unwanted noise in your rig, or perhaps even use it as a tone-tool for sculpting aggressive rhythm guitar textures, depends on how you connect it to your rig, and understanding just how it works.


At first glance, you’ll see the NS-2 has 4 jacks. You’d be mistaken for thinking it’s a stereo in/out pedal, when in fact they are INPUT/OUTPUT and SEND/RETURN jacks. These jacks allow the NS-2 to be configured in 2 different ways, depending on your rig and your desired outcome.

For the purposes of this article, we’ll refer to these two different configurations as the SIMPLE method and the ADVANCED method.


This is the simplest way to use the NS-2. Simply insert the NS-2 into your signal chain as the last item AFTER your noisy pedals or amp.

SIMPLE METHOD with an Overdrive pedal:
NS-2 OUTPUT >> Amplifier INPUT

NS-2 Noise Suppressor Diagram

SIMPLE METHOD with a High-Gain Guitar Amp* (*must have an FX Loop):
GUITAR >> Amplifier INPUT
Amplifier FX SEND >> NS-2 INPUT
NS-2 OUTPUT >> Amplifier FX Return

NS-2 Noise Suppressor Diagram

The SIMPLE method, as the name implies, is simple to implement (you just connect it in-line, as you would any other effects pedal) and very effective at killing noise.

The limitation with the Simple method is that at high noise levels (common with high gain pedals and amps), the Noise Suppressor has difficulty in determining what is noise and what is your actual guitar signal.

Once the total signal level (guitar signal + noise) reaches the pedal’s detection threshold, the NS-2 will cut ALL sound – both the unwanted noise AND the guitar signal. This can manifest a problem when playing long sustained notes with high preamp gain. As the note starts to die out, the Noise Suppressor in Simple mode may end up “clamping down” and cutting the end of the note off.

This effect can actually be desirable for some players. Guitarists who play high-gain, staccato rhythms often relish the “choppy” effect that the Simple Method can deliver. If you are looking to use a Noise Suppressor to “tighten up” your high gain rhythms, then the Simple connection method may be best for you.

However, for many players – this somewhat “unnatural” response can be considered detrimental to guitar tone and an invasive playing experience. To combat this problem, the NS-2 was designed with an intelligent “detection circuit” designed to differentiate between your guitar signal and unwanted noise. To take advantage of this functionality, we can connect using the ADVANCED method.


The Advanced method, (sometimes called the “4 cable method” or the “X-Method/X-Pattern”) makes use of the NS-2’s intelligent detection circuit, by using all 4 jacks. The INPUT of the NS-2 contains the guitar signal detection circuit; whereas the actual noise suppression circuit is located within the SEND/RETURN loop of the NS-2.

Detailed below is how to make the connections:

ADVANCED METHOD with an Overdrive pedal:
NS-2 OUTPUT >> Amplifier INPUT

NS-2 Noise Suppressor Diagram

ADVANCED METHOD (a.k.a. “X-method”), with a High-Gain Guitar Amp* (*must have an FX Loop):
NS-2 SEND >> Amplifier INPUT
Amplifier FX SEND >> NS-2 RETURN
NS-2 OUTPUT >> Amplifier FX Return

NS-2 Noise Suppressor Diagram

What all that means, is that you’re using your guitar to trigger the noise reduction circuitry of the NS-2 so it can work out how much noise it needs to cut before it tackles the rest of your rig.

When correctly connected using this method, the NS-2 will “detect” your guitar’s signal and allow the noise suppression circuit to activate only as your guitar signal dies out, resulting in a more natural guitar sound.
The NS-2 was the first pedal to achieve this style of noise suppression and remains an industry standard still today.

Once you have the pedal connected in either method, the NS-2 becomes an invaluable tool. The key to optimum results, is understanding just what the main control knobs do.


NS-2 Noise Suppressor

The THRESHOLD control sets how sensitive you wish the Noise Suppressor to be, i.e. the “threshold” at which the Noise Suppression begins to do its work. Setting the THRESHOLD all the way to MAX will cut nearly anything, including guitar signal. If you want to back it off a bit, you’ll also be able to still get nice feedback swells if you desire. A bit of breathing room here can be good.

The DECAY control allows you to set to how fast or slow you want the signal to fade out when the suppression circuitry kicks in. Slower DECAY settings will give a more natural overall guitar sound, and avoid the end of long notes being “chopped off” as they die out. Faster DECAY settings are favoured amongst many metal guitarists for the way in which it creates a “choppy” sound that suits tight, high gain rhythm playing.

The MODE SELECTOR knob offers options for different ways to utilise the NS-2.

In REDUCTION mode, the NS-2 will suppress unwanted noise, as determined by the Threshold. To activate Reduction mode, simply select it via the Mode Selector and press the pedal ON.

In MUTE mode, the NS-2 will MUTE your sound completely once the pedal is switched on – like a kill switch, giving you dead silence.

If the pedal is not switched on in Mute mode, the pedal will work the same as it would in Reduction mode. Essentially, Mute mode does not have a bypass feature. It will reduce your noise but will kill all sound when you step on the pedal.

REDUCTION MODE: Bypass (pedal off) / Reduction (pedal on).
MUTE MODE: Reduction (pedal off) / Mute (pedal on).



Ok, good question. You can absolutely use effects and other pedals with the NS-2!


Keep in mind that the NS-2 has a DECAY feature. That means, if you put delay/reverb and time based effects BEFORE it, it might cut off those nice ambient trails. Best way to use reverb and delay effects with the NS-2 is to put them AFTER it does its work. You can also put modulation pedals here if you want too.

NS-2 Noise Suppressor Diagram

We’ve discussed using overdrive pedals with the NS-2 earlier in this article. But, if you’re using the 4-cable or “X-method”, the only pedal you should plug into before the NS-2 is your tuner.

Whichever setup you choose, the BOSS NS-2 Noise Suppressor will clean up your overall sound while maintaining the dynamics and nuances of your playing. It will also preserve your tone, no matter if you’re using a large pedal/effects setup or a simple guitar and amp rig. Certainly a crucial pedal for live, studio and rehearsal use, (almost as much as a tuner is!), the BOSS NS-2 is your go-to tool for clear and unobstructed tone.

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