10dB DOUBLE – Free Vocal Doubler Plugin (VST3 / AU)

10dB DOUBLE is a free vocal doubler plugin that turns one vocal take into a thick, wide double-tracked sound. It is made for home-studio singers, rappers, producers and mix engineers who want the “two takes” effect on a lead vocal, backing vocals or an ad-lib track without recording the part again. It runs as a VST3 on Windows and Mac and as an Audio Unit in Logic Pro and GarageBand.

What does a vocal doubler actually do?

When a singer records the same line twice and the two takes are played together, tiny differences in timing, pitch and tone make the vocal sound bigger and richer than one take turned up. That is double tracking. In the 1960s, engineer Ken Townsend at Abbey Road Studios developed Artificial Double Tracking (ADT): a second tape machine played back a delayed copy of the vocal so the band did not have to sing everything twice.

A doubler plugin does the same job digitally. It creates extra copies of the vocal, delays each one slightly, shifts its pitch by a few cents and spreads the copies across the stereo field. The difference between a good doubler and a cheap chorus is movement: real takes are never perfectly in time or in tune, so a convincing double has to drift a little too.

Up to four voices that behave like separate takes

10dB DOUBLE adds one to four voices on top of your original vocal. Each voice has its own delay offset and its own pitch offset, alternating sharp and flat, so the voices never line up into one obvious copy.

• VOICES (1-4) – 1 gives a centred ADT thickening, 2 places a double left and right, 3 adds a centre voice, 4 adds an inner left/right pair.
• DETUNE (0-30 cents) – how far each voice is pitched away from the original. 5-10 cents sounds natural; higher values move towards a chorus sound.
• DELAY (5-60 ms) – how far behind the lead the voices sit. Short delays thicken, longer delays sound more like a separate performance.
• DRIFT (0-100%) – slow random movement of timing (up to ±2.5 ms), pitch (up to ±6 cents) and level (up to ±1.5 dB) for every voice.

Width you can see

The large display shows the original vocal as the centre dot and every double as a glowing dot placed where it sits in the stereo field. As you raise WIDTH the dots move out towards the speakers, and with DRIFT turned up you can watch them wander slightly, just as a second take would. The power button gives a click-free bypass, so you can compare the doubled and dry vocal in context.

Low Cut and Mix: wide doubles, solid low end

Low frequencies are where doubles cause trouble: they muddy the mix and can thin out when the track is played in mono. LOW CUT (20-500 Hz) filters only the doubled voices, while the original vocal stays untouched. Between 150 and 250 Hz is a good starting range for most lead vocals. MIX blends the doubles in: at 50% you hear the dry vocal and the doubles at full level, and at 100% you hear only the doubles, which is ideal when DOUBLE sits on an FX/send channel.

Who is it for?

• Singers and producers recording at home who want a bigger chorus vocal without stacking extra takes.
• Rappers and hip-hop producers who want wide ad-libs and hook doubles.
• Mix engineers who need a quick, natural double for a lead, backing vocals, guitars or synth lines.
• Not designed for spoken word: doubling makes podcast or video dialogue sound unnatural.

If you can record a real second take, do it for the most important parts. A doubler is the fast, consistent option when the singer has gone home, the take cannot be repeated, or you want doubles on every line without editing them.

Quick starting points

• Natural Double – two voices left and right, light detune and drift. The everyday lead vocal double.
• Tight ADT – one centred voice with a short delay for classic thickening without width.
• Wide Pop Vocal – full width for big modern choruses.
• Big Stack – four voices with more detune and drift for a gang-vocal or stacked-hook feel.
• Rap Ad-libs – short delay, low drift and a higher low cut for punchy, wide ad-libs.
• Subtle Thickener – a gentle blend that adds body without sounding like an effect.

10dB DOUBLE vs other free vocal doublers

iZotope Vocal Doubler is the best-known free option. It is very simple: one control pad sets stereo separation and human variation, plus an amount control, and it also comes in AAX for Pro Tools. 10dB DOUBLE gives you separate control over the number of voices, detune, delay, low cut and width, plus presets and a live display, but it has no AAX version.

Acon Digital Multiply is a free multi-voice chorus. It is great for thickening backing vocals and instruments, but it is built as a chorus rather than a vocal doubler, so it has no dedicated delay-per-voice or vocal presets.

Many producers keep more than one doubler and pick per song. DOUBLE is designed for the most common job: a natural, controllable double on a lead or backing vocal in a few seconds.

How to get the best results

• Use it on a stereo track or an FX/send channel. On a mono track some DAWs, such as Cubase, keep the output mono, so you get thickness but no width.
• Double the chorus and leave the verse dry: the change in width makes the chorus lift.
• Keep DETUNE low (5-12 cents) on lead vocals; push it higher on backing vocals.
• Check your mix in mono. If the vocal sounds hollow, lower WIDTH or MIX, or raise LOW CUT.
• Pair it with a clean vocal recording: a good condenser microphone and audio interface give the doubles more detail to work with.

Key Features

• Free vocal doubler plugin for Windows and macOS (VST3) and Logic Pro / GarageBand (AU)
• 1 to 4 doubled voices with alternating detune and per-voice delay spread
• Detune 0-30 cents, Delay 5-60 ms
• Drift: natural random timing, pitch and level movement
• Width 0-100% with a live stereo display
• Low Cut 20-500 Hz on the doubles only
• Mix 0-100% for insert or FX/send use
• Works on stereo tracks and mono-in / stereo-out
• Zero latency and click-free bypass
• 6 presets, resizable interface
• Universal macOS build (Apple Silicon and Intel)

Looking for more free tools? Browse all VST plug-ins from 10dB.

Frequently asked questions

Is 10dB DOUBLE really free?

Yes. There is no trial, time limit or paid upgrade. Add it to the cart, check out with your name and email, and the Windows and Mac downloads appear on the order page and in your confirmation email.

Why does it not sound wider on my vocal track?

Your track is probably mono. In some DAWs, Cubase included, a mono track stays mono after the plugin, so the doubles add thickness but cannot spread left and right. Put DOUBLE on a stereo track or an FX/send channel (with MIX at 100%) to hear the full width.

Will doubling cause phase problems in mono?

Any doubler adds delayed copies, so some comb filtering in mono is normal. LOW CUT keeps the bass and low mids of the doubles out of the way, and keeping MIX around 30-50% on lead vocals keeps the original in front. Always check the chorus in mono before you bounce.

Does it work in Ableton Live, FL Studio, Cubase, Logic Pro and Pro Tools?

It works in any DAW that loads VST3 plugins (for example Ableton Live, FL Studio, Cubase, Studio One and Reaper) and, on Mac, in hosts that use Audio Units such as Logic Pro and GarageBand. Pro Tools needs AAX, which DOUBLE does not support.

My Mac says the installer can’t be verified. What do I do?

The installer is not signed through Apple’s paid developer program yet. On macOS 14 or earlier, right-click the .pkg file, choose Open, then Open again. On macOS 15 or later, try to open it once, then go to System Settings > Privacy & Security and click Open Anyway.

Chrome says the file “isn’t commonly downloaded”. Is it safe?

That message appears for new files that few people have downloaded yet, not because a problem was found. Click the download, choose Keep, and continue. The warning fades as more people download the plugin.