The most requested feature from our users is now implemented: Undertone 1.2.4 supports Audiosuite handles.
Undertone is a semi-random ambience and texture generator, sound multiplier and drone maker, based on granular and convolution synthesis.
It can create dialogue fills, evolving soundscapes and sound fx from short audio samples.
Undertone is a Pro Tools AudioSuite plug-in (for MacOS and Windows) made by sound editors for sound editors. Try it now!

Only€199 (tax excl.)


New in version 1.2.4

  • Support for Audiosuite handles
  • New improved UI for Single Mini mode
  • Fixed a bug that could cause Pro Tools to crash when working in Multi mode 

New in version 1.1

  • Surround Panner (up to 7.1) with random grains position 
  • Seed based random functions: can be locked to always render the same sound 
  • Relative control of parameters across multiple slots
  • Faster rendering in Single mode
  • Multiple UI improvements,  refinements and more

Musica by Bewider

Some of the things you can do with Undertone:

  • Easily create fills for dialogue editing
  • From single sound to multitude in a few clicks
  • Create surround ambiences from mono production sound recordings
  • No more loops if you need more audio material
  • Randomly spawn sounds
  • Design ever changing and dynamic sound textures from short audio samples
  • Create M&E fills in seconds

From simple room tones and fillers to complex and rich backgrounds, from realistic environments to otherworldly sounds and drones.
Undertone is the breath of randomness that add life and movement to any sound.

The more you use it, the more you will be inspired.

Single Mode

The simple but effective mode generates constant and natural audio flows related to the sound content in the active slot.

Pitch and Level randomness can be controlled by the user to create more static or dynamic sounds. In Single Mode is also possible to mix the granular engine with a convolution engine: an easy way to add movement and variation to static tones. But usually you don’t need to tweak any parameters: default settings produce great results.

A true holy grail for every dialogue editor!


Multi Mode

The more powerful and experimental side of Undertone, but still very easy to use and control. Undertone becomes an original granular synth that uses all the slots as grains source. Up to 10 slots (sounds) can be active at the same time and can be used to generate complex and dynamic sounds. Each slot has its own parameters (Volume, Pitch, Envelope, Grain Duration, Pitch Randomness and Volume Randomness) which will affects the grains generated by Undertone.

Every new grain is seeded randomly with the content of one of the active slot: the Probability of each slot can be set by the user along with the waiting time (Recovery Time) between each selection of the same slot.

GUI Capture

Load audio directly from your timeline using Undertone’s custom Capture buttons on each slot.


Type the name you want to place on the rendered clips (like the scene number or the texture mood that you’ve just created).

Dynamic Tips

If you want to jump into Undertone you never feel lost: move the cursor on a control to have an instant feedback from the Tips Overview.

Mini Modes

You can choose the size of Undertone: each mode has its own mini version with an essential view of Undertone’s controls, in order to fit your workflow.

Mixer Grain Convolver

With the granular/convolution control you can mix the Granular and the Convolution engines, and find the perfect balance between random and constant sounds.

History Panel

Keep track of your work with the History Panel.
Each element on the list is an Undertone snapshot, stored on render: just click to recall it.


Have access to a growing libraries of Tones designed by our team and by featured designers. Free to use for all our users.
Undertone ships with TonePacks from U.S.O. Libraries and Wider Audio.

Undertone saves its entire state, even the audio, in a single .tone file ready to be reused or shared.

View all TonePacks

User Stories

Michael Maroussas
Supervising dialogue editor
(Chernobyl, Black Mirror, Darkest Hour)

“Undertone is now an essential in my dialogue editing toolbox – for creating clean fill, fill with movement in it, for continuing bg noises such as planes or car noise which is often hard to fill, for elongating screams…you name it. And it’s a must-have for creating DX sessions for M&E too. Strongly recommended!”

Helen Luttrell
Dialogue Supervisor
(Jojo Rabbit, The Tree of Life, X-Men: Days of Future Past)

“Ok so I absolutely love this plugin, one of my all time favourites.   It is currently saving me huge amounts of time and anguish, I use it almost on every scene plus it is getting me out of some very tricky dx editing situations.  It’s friggin genius/awesome!!  I would be lost/grumpy without it.  Many thanks guys.”

Matteo Milani
Sound Designer & Founder @ Unidentified Sound Object

“The grown up kids @ Audiokids have enclosed in a unique and friendly device two of my desert island DSP tools: granulation and convolution. Once you’ve started using Undertone, it’s addictive… primarily for the tiny but important tasks such as creating air fills for dialogue tracks. Watch out though: it’s a powerful instrument to create complex soundscapes and atmospheres in an intuitive, simple interface. Kudos to Davide, Fabrizio and Mattia!”

Dario Ramaglia
Dialogue Editor and Re-Recording Mixer
(Devils, Medici)

“Undertone is a must-have for dialogue editors, that’s it. It’s a tiny little tool, very easy to use and yet a game changer.
Creating believable room tones with just a bunch of frames of usable audio has always been a struggle for dialogue editors: not anymore. Now that Undertone is in my toolkit, I can’t live without it.”