Get Massive Width: The Best Free Doubler Plugin Options

Every metal producer is on a quest for that massive, wall-of-sound mix. You want guitars that feel wide enough to fill the entire room and vocals that cut through with authority. One of the most effective tools for achieving this is a doubler. It’s the secret sauce behind countless iconic metal tones.

But let's get one thing straight: having a fancy plugin doesn't automatically make your mixes better. The real magic isn't in the tool, but in how you use it. A great mixer can get insane results with stock plugins because they understand the fundamentals. That said, having a great starting point helps.

So, let's look at some absolutely killer free doubler plugin options and, more importantly, how to use them to get pro-level width in your metal productions.

What's a Doubler and Why Do I Need It?

You can’t just duplicate a guitar track, pan it left, and pan the original right. All you’ll get is a slightly louder mono signal. A doubler plugin (or a manual doubling technique) creates the illusion of a second, unique performance by introducing tiny variations in timing and pitch between the original signal and a new, copied version.

This psychoacoustic trick, often leveraging the Haas effect, makes the sound source feel wider, thicker, and more substantial.

Common uses in metal:

• Rhythm Guitars: Turning two tracked guitars into an impenetrable wall of four.
• Lead Vocals: Adding thickness and presence to a lead scream or vocal melody without burying it in reverb.
• Guitar Solos: Making a single lead line feel more epic and heroic.
• Synths & Pads: Adding stereo interest and depth to atmospheric elements.

Top Free Doubler Plugins You Can Download Now

You don't need to drop hundreds of dollars to get a killer doubling effect. These freebies are more than capable of getting the job done.

iZotope Vocal Doubler

Even though it says "Vocal" in the name, this thing is a monster on guitars. iZotope Vocal Doubler is probably the most straightforward and effective free doubler on the market. The interface is dead simple: drag a node around an X/Y pad to control the amount of human-like variation ("Variation") and stereo width ("Separation").

How to Use It for Guitars

For maximum rhythm guitar width, push the Separation fader all the way up. Be careful with the Variation control; setting it too high can make your tight riffs sound sloppy. Start with it low, around 10-15%, to add just enough micro-variation to sound authentic. The "Effect Only" button is super useful for processing the doubles separately on an aux track.

How to Use It for Vocals

On a lead scream, you often want thickness more than obvious width. Try pulling the Separation back to around 40-50% and dial in the Mix knob to taste. This will tuck the doubled voices just behind the main vocal, giving it weight without the distracting "effected" sound.

Acon Digital Multiply

On the surface, Acon Digital Multiply is a chorus plugin, but it’s so versatile that it works beautifully as a doubler. It gives you independent control over the modulation rate and depth for up to six voices, plus a built-in EQ to shape the wet signal.

How to Tame It for Doubling

To use it as a doubler instead of a warbly chorus, you need to kill the modulation. Turn the Modulation Rate all the way down to 0 Hz. Now, use the Modulation Depth and the Voice Count to control the character of your doubles. The built-in EQ is a game-changer—you can instantly high-pass the doubled signal to keep your low-end clean, which is a crucial move.

Valhalla Supermassive

Everyone knows Valhalla Supermassive as a mind-bendingly good free reverb and delay, but some of its modes are perfect for creating doubler-style width. It’s all about short, non-feedback delay settings.

How to Use It for Spaced-Out Width

Try the Gemini or Hydra modes. Pull the MIX knob to 100%, set the DELAY to a very short time (try 15-40ms), and bring the FEEDBACK knob all the way down to 0. Now, use the WARP and DENSITY controls to shape the timing and texture of the "doubles." This won't be as tight as a dedicated doubler, but for atmospheric leads or clean passages, it can create a gorgeous, washed-out stereo image.

The DIY Doubler: Manual Techniques for Ultimate Control

Relying on a plugin is fine, but understanding how to create the effect from scratch gives you ultimate control. This is where your skills as an engineer truly shine. All you need are your DAW's stock plugins.

1. Duplicate the Track: Take your mono source (e.g., a lead guitar) and duplicate it onto a new track.
2. Pan Hard Left & Right: Pan the original track 100% left and the duplicate 100% right.
3. Add a Sample Delay: On the duplicated track only, insert a basic delay plugin. Don't use a tempo-synced delay; you need one that lets you set the delay time in milliseconds (ms). A setting between 15-35ms is a great starting point.
4. Slightly Detune (This is the critical step!): On that same duplicated track, insert a pitch-shifting plugin and detune the signal by a tiny amount, somewhere between -7 and +7 cents. This is what separates it from a simple Haas delay and really sells the illusion of a different performance.

This manual method prevents the nasty, hollow phasing you get from just delaying a signal and gives you a thick, stable, and wide sound.

Beyond the Plugin: Pro-Level Doubling Concepts

EQ and Compress Your Doubles Differently

Your doubled signal shouldn't be an exact copy of the main signal. It's a supporting element, so it needs its own space.

• EQ: Send your doubled signal to its own bus and EQ it aggressively. Use a high-pass filter to cut out all the low-end mud below 150-200Hz. Carve out the midrange (400-800Hz) with a wide bell curve to make room for the punch and body of the main performance. You may even want to roll off some of the top-end fizz to push it further into the background. For more in-depth strategies, check out these advanced techniques for EQing metal guitars.
• Compression: Sometimes, compressing the doubled signal can help tuck it into the mix and give it a consistent level. You don’t need to be subtle here; the goal is to control the dynamics so it creates a solid "bed" for the main track to sit on. Learn more about how the pros use compression in metal mixes.

Watch Out for Phase and Latency

Every plugin you add introduces a small amount of processing delay (latency). Modern DAWs have Automatic Delay Compensation (ADC) to manage this, but it’s not always foolproof, especially with complex parallel processing.

If your doubler plugin has high latency and it's on a parallel aux track, it can arrive slightly later than your dry signal, causing phasing issues that can make your tone thin and weak. Always check your mix in mono to ensure your wide sounds don’t disappear completely. If they do, you have a phase problem that needs fixing.

Your Skills Matter More Than Your Tools

At the end of the day, it doesn't matter if you use a free plugin or a $300 one. It doesn't matter if you use the same tools as Jens Bogren, Nolly Getgood, or Will Putney. Your mix is a product of thousands of small decisions, all guided by your taste and your skill.

These free doubler plugins are fantastic tools. But they're just that—tools. The real growth comes from learning the why behind every move.

Imagine watching the engineers behind bands like Gojira, Lamb of God, and Periphery build a mix from scratch, explaining why they're choosing a specific delay time, how they're EQing their doubles, and how they're making it all work with the bass and drums. That's what we do at Nail The Mix. Every month, you get the real multitracks from a massive song and watch a world-class producer mix it in real-time.

Explore our full catalog of mixing sessions and see for yourself how the best in the business turn raw tracks into polished, powerful metal.