How to use noise gates in your amp-sim chain (and why placement is everything)

800 milliseconds. That's roughly how long the hiss tail from an uncontrolled high-gain amp-sim patch hangs in the air between palm mutes before it completely ruins a mix. I know because I've sat in a session room listening back to a track I thought sounded killer and watched an engineer's face drop when he soloed the guitar bus.

Noise gates fix that — but only if you put them in the right place and actually know what you're adjusting. Most players either skip the gate entirely or slap one at the front of the chain and wonder why it chops the attack off every note they play. So let's sort this out properly.

Why high-gain amp sims generate so much noise

The short version: gain stages amplify everything, not just your guitar signal. Every bit of interference your cables pick up, every tiny bit of electrical hum from your computer's USB bus, the buzz from a ground loop between your audio interface and laptop — all of it gets multiplied by the same factor as your guitar. Stack three or four gain stages in a modern amp-sim (pre-amp, power-amp, maybe a drive pedal in the chain before it) and you're amplifying that noise by an enormous amount.

Active pickups — EMGs, Fishmans, that sort of thing — are generally quieter at the source, which helps. But even a Fishkel Fluence going into a Fortin-modelled amp sim with the gain at 7 will still produce enough noise floor to be a problem in a recording context. Passive humbuckers are worse. Single coils worse still. The sim doesn't care; it just amplifies what it gets.

If you're running a guitar like the Schecter Hellraiser C-1 (check price) with its active EMGs, you've got a head start on noise control — but you still need a gate in the right position.

The two placements — and why they do completely different jobs

Here's the part most tutorials skim over. A noise gate placed before your amp sim (i.e., in the input chain, pre-distortion) kills the noise that's coming from your guitar and cable. A gate placed after the sim (post-distortion, in the output path) kills the noise the gain stages themselves generate.

You often need both.

Pre-gate: this is listening to your relatively clean guitar signal. Set the threshold low enough to catch hum and interference but high enough to open cleanly when you actually play. Because the signal it's watching is clean and transient-rich, it can react fast without chopping your pick attack. This is where you stop that 60-cycle hum from your laptop charger getting muliplied by the amp sim.

Post-gate: now the gate is looking at a fully-distorted, compressed, harmonically saturated signal. Thresholds need more careful dialling here because a heavily compressed gain signal has a much flatter dynamic envelope — the difference between "guitar ringing out" and "guitar silent" in level terms is smaller than you'd think. Go too aggressive and it clamps down on sustained notes and reverb tails. Too gentle and it lets the hiss breathe freely between riffs.

In most amp-sim software — Neural DSP, Line 6 Helix Native, the Kemper plugin, whatever you're running — you can insert a noise gate block before the amp section and another in the FX loop or after the cab block. Do both. The front gate handles your instrument noise; the rear gate handles the amp's own noise floor. Honestly, getting these working together is what separates a DI recording that sounds pro from one that sounds like a demo recorded in a server room.

How to actually set the threshold without ruining your sustain

This is where players get it wrong more often than not. They set the threshold by ear in isolation — they hear the hiss stop, they're happy, done. Then they record and realise every note shorter than a quarter-beat is getting chopped, every palm mute is stuttering, and held chords are dying three seconds too early.

Better method: play the part you're actually going to record. Watch your DAW's input meter while you do it. Note the lowest level you hit while actively playing — that's the floor of your playing dynamic. The noise floor when you're not playing is somewhere below that. Your threshold needs to sit between those two values, closer to the noise floor than to your quietest playing level.

For a typical high-gain metal patch with passive humbuckers, I usually find the threshold ends up somewhere around -50 to -45 dBFS on the pre-gate and maybe -40 to -35 dBFS on the post-gate. Those aren't rules — they're just where I tend to land. Your rig will be different.

Attack time matters too. Too fast on a post-gate and it clicks when it opens. 5-10ms of attack smooths that out without losing the percussive quality of a tight djent pattern. Release is the one people really get wrong — set it too short and the gate snaps shut audibly mid-sustain. I usually start at around 200ms and back off if it's catching my longer notes.

Dealing with noise gates and specific techniques

Palm muting is the big one. Heavy mutes already have a natural dynamic shape — the pick attack, then a quick decay under the heel of your hand. If your gate's release is too fast, it clamps down on the resonance under the mute and makes everything sound dead and flat rather than tight. Slightly longer release times (250-300ms) usually preserve that texture.

If you've read through the piece on how to dial in high-gain amp-sim tones at home — wait, that's actually our existing article on this — then you know the amp-sim EQ decisions and how they interact with perceived tightness. Gates and EQ work together: a leaner low-mid response means the gate has less murky sustained energy to deal with, which means it can close more cleanly.

Legato runs are the other tricky case. Hammer-ons and pull-offs without a pick attack produce a softer signal. If your pre-gate threshold is a touch too high, it'll fight you on anything you play without a hard pick stroke. On legato-heavy parts I'll sometimes temporarily lower the pre-gate threshold during recording and then bring it back up for the rhythm sections. Or I'll just automate the gate bypass. Either way, be deliberate about it rather than setting it once and forgetting it.

Hardware vs software gates — does it matter?

If you're running straight into an audio interface and using amp-sim plugins in your DAW, software gates are fine. The ISP Decimator is legendary as a hardware unit and I've got one in my live rig, but in a recording context where I'm working in the box, I just use whatever gate is available inside the sim or a plugin like the standard gate in Logic or Reaper. The ISP's tracking algorithm is honestly better for live use where you're playing in real time and need it to respond to picking dynamics across multiple guitars in a loud stage mix.

For home recording into an interface, a well-configured plugin gate will do the job. Save the hardware outlay for your actual guitar and pickup choices — a quieter source signal is always better than fighting noise with a gate after the fact.

One more thing — check your gain before you gate

Gates are a fix, not a cure. If you're running the gain on your amp sim at 9 when the tone you actually want only needs 6, you're generating extra noise for no sonic reason. I see this constantly. Players crank gain because it feels heavier, but recorded high-gain tone almost always benefits from slightly less gain than you think you need — the mix compression and the low-mid EQ cut does the rest. Less gain means a quieter noise floor, which means your gate has an easier job, which means your sustain stays natural and your attack stays intact.

Sort the gain first. Then place the gates intelligently, front and back. That's the chain that actually records clean.