Compressor vs noise gate

They do opposite things to the quiet part of your signal. A compressor lifts quiet sounds toward the loud ones, which makes uneven picking even and also makes hiss louder. A noise gate mutes everything below a threshold, which removes hiss between phrases and does nothing about noise you can hear while a note is ringing. If your problem is uneven playing, buy the compressor. If it is hiss in the gaps at high gain, buy the gate. Buying the compressor for a noise problem makes it worse.

These get shelved together and described with the same word — dynamics — which is how people end up with the wrong one. The distinction is simple once stated and almost never stated.

01What each one does to the quiet part of your signal

Read the last row twice, because it is the most expensive misunderstanding in this category. Neither of these pedals fixes a hum you can hear underneath a note you are playing. That is a power or shielding fault — your pedalboard hums sorts the five faults that all get called the same thing.

02 — The shortlist

Which one do you need

#	Product	Best for	Price
01	Keeley Compressor Plus Lifts the quiet parts toward the loud ones, with a blend control so the attack survives.	Quiet notes that should be louder	$149.00 · Check price #ad How we’re funded · price as of October 17, 2026
02	BOSS NS-2 Noise Suppressor Mutes your output when you stop playing, with a send/return loop so the gate can watch your clean signal.	Hiss in the gaps between phrases	$120.99 · Check price #ad How we’re funded · price as of October 17, 2026

Rows link to the full write-up further down this page. Prices come from the live price layer only — where there is no live figure the button reads “Check price” rather than showing a remembered number.

03Why the compressor makes noise worse

A compressor narrows the gap between loud and quiet. Whatever it does to a quiet note it also does to a quiet noise, because the circuit cannot tell them apart — it is responding to level, not to meaning.

So a hiss that sat harmlessly below your playing comes up with everything else, and the more compression you use the more audible it becomes. This is why compressor and gate turn up on the same boards: the compressor creates or exposes the noise problem the gate then manages. They are not alternatives so much as a sequence.

01

Keeley Compressor Plus

Quiet notes that should be louder

The number10 mA, true bypass, 100% analog. Published by Keeley.

A compressor reduces the distance between your loudest and quietest notes, and the way it is normally used, it does that by bringing the quiet ones up. If some notes jump out and others vanish, that is the tool.

The blend control is what makes it usable at strong settings: the dry transient passes at full strength while the compressed signal fills in behind, so notes still sound picked. The Release switch has two positions Keeley tunes for single coils or humbuckers.

The cons: no attack knob and release is a switch rather than a continuous control, Keeley publishes no impedance figures, and — the part that matters on this page — it makes hiss louder, not quieter. Compression lifts quiet signals, and noise is a quiet signal.

Published specifications for the Keeley Compressor Plus

Controls	Sustain, Level, Blend and Tone knobs, plus a Release switch
Release switch	Two positions, which Keeley describes as tuned for single coils or humbuckers
Blend	Mixes the compressed signal against the dry signal for parallel compression
Current draw	10 mA
Power	9 V DC, center negative; Keeley also lists battery operation
Bypass	True bypass
Circuit	100% analog
What it does not do	No attack knob, and release is a two-position switch set for pickup type rather than a continuous control — the blend knob is how you keep the transient, not a time constant. Keeley publishes the current draw but no impedance figures.

Specs from Keeley Compressor Plus product page. We have not used this unit.

$149.00 · Check price

#ad How we’re funded · price as of October 17, 2026

02

BOSS NS-2 Noise Suppressor

Hiss in the gaps between phrases

The number25 mA, with Input, Output, Send, Return, DC IN and a 9 V DC OUT.

A gate does the opposite: it mutes your signal when you are not playing. That is a genuine fix for high-gain hiss between phrases, and no fix at all for a hum you can hear underneath a held note — the gate is open while you play.

The send/return loop is the feature worth buying it for and the one most owners never wire up. Put your dirt pedals inside the loop and the gate decides from your clean guitar signal when you are playing, while muting the noisy chain's output. Used as a simple in/out pedal it has to make that decision from an already-distorted signal, which is why it then chops sustain.

The cons: BOSS is explicit that it suppresses rather than removes, so a constant hum survives it. The simple configuration audibly shortens sustain. And it is another box plus two more patch cables in a chain you are trying to quieten.

Published specifications for the BOSS NS-2 Noise Suppressor

Controls	Mode switch, Decay, Threshold, pedal switch
Jacks	Input, Output, Send, Return, DC IN, 9 V DC OUT
Send/Return loop	Lets the gate listen to the guitar directly while muting the output of the noisy pedals
Circuit	VCA with a high-speed envelope detector
Current draw	25 mA
Weight	415 g including battery
What it does not do	It suppresses noise, it does not remove it — a gate cannot clean up a hum you can hear through a held note. Used in the simple in/out configuration it also cuts your sustain, which is why the send/return loop exists.

Specs from BOSS NS-2 specifications. We have not used this unit.

$120.99 · Check price

#ad How we’re funded · price as of October 17, 2026

04Diagnose before you buy

1. Some notes jump out, others vanish. Dynamic range. Compressor.
2. Hiss between phrases, worse with more gain. Noise floor. Gate, ideally using its send/return loop.
3. Sustained notes die before the phrase ends. Compressor.
4. A hum you can hear under a held note. Neither. Power or pickups.
5. Clean parts sound uneven and lifeless in a recording. Compressor, with a blend control so the attack survives.
6. High-gain rig that roars between songs. Gate.

05Do you need both

On a clean or moderately driven board, almost never. A compressor alone is the common case, and at those gain levels there is little noise to gate — a gate would mostly clip the tails of your notes for no benefit.

On a high-gain board, frequently yes, and in that order. The compressor does its job in front of the dirt, the dirt amplifies everything including the noise floor, and the gate manages what comes out. Best compressor pedals and best noise gates cover the two categories, and best pedals for metal is the context where the gate is the first purchase rather than the last. Once you have established that a gate is what you need, ISP Decimator X vs BOSS NS-2 is the head-to-head between the two that matter.