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When working with linear audio that contains gaps of silence or recalls repeated audio, precious space can be saved by editing within your Pro Tools session and exporting the resultant files and session data for programming.

George Hufnagl, Blogger

August 16, 2012

6 Min Read

This blog was originally posted on Creating Sound. Additional information about the author and website can be found at CreatingSound.com


When working on projects with limited audio space, such as apps for mobile, browser-based games or packaged electronics/toys, it is often necessary to squeeze as much out of that space as possible in order to meet or exceed the expectations of the project. From the standpoint of the sound designer, this is likely achieved through compressing the sound files in various ways. However, when working with linear audio that contains gaps of silence or recalls repeated audio, precious space can be saved by editing within your Pro Tools session and exporting the resultant files and session data for programming. While the processes for identifying and editing these two elements are different, their functionality in implementation is essentially the same. In Part 1, I cover the process for getting started, staying organized, and identifying and removing silent gaps.


What’s needed:
*Pro-Tools (This tutorial is conducted in Pro Tools 9)
*Linear audio (e.g Dialogue)
*Playlist Dividers and Mutes (Short, silent files that you can create yourself, or download this .zip file)
*Access to spreadsheet software (This tutorial uses Excel)
*An understanding programmer

The example in this tutorial refers to a project I worked on that was intended to help children learn to count in German through repetition. It consists of 28 different sound files, comprising both dialogue and sound effects. Of the files that consist of only dialogue, many follow this pattern:

Sound File Example 1: “Eins. / Zähl bis / eins. / Eins. / Wow!”
Sound File Example 2: “Zwei. / Zähl bis / zwei. / Eins. / Zwei. / Gut gemacht!”
Sound File Example 3: “Drei. / Zähl bis / drei. / Eins. / Zwei. / Drei. / Super!”


Sound File Example 1: "One. / Count to / one. / One. / Wow!"
Sound File Example 2: "Two. / Count to / two. / One. / Two. / Well done!"
Sound File Example 3: "Three. / Count to / three. / One. / Two. / Three. / Great!"

Without regard for silent gaps or repetitious audio, the sum total of the audio for this project would have been over three and half minutes. See below:

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Since there was not enough space to accommodate that amount of audio, it was imperative that I find a way to cut down.


When working on projects like this in which multiple sound files will be edited within a track, discerning where files begin and end can be difficult. Therefore, I use a newly-created file I call the “Playlist Divider.” This is a silent demarcation placed at the beginning of each separate sound file to keep the session and resulting documentation organized. See below:

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(“Playlist Divider”)

The “+” sign is used to keep the Playlist Divider at the top of the REGIONS file list for easy access. Here is an example of its use within the Pro Tools session. See below:

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(Implemented Playlist Dividers)

The middle series of files appear to be separate, but they are all part of the same line of text. With the help of the Playlist Dividers, the line “Drei. / Zähl bis / drei. / Eins. / Zwei. / Drei. / Super!” stands apart from the others that precede and succeed it. When it comes time to export the session, this organization will be key in formatting the information, which will be addressed later in this tutorial.


Side Note: While going through this editing process, I recommend staying in "SHUFFLE" mode to retain the integrity of the space when removing and replacing silent gaps.

Assuming the project’s audio has been approved for implementation, it’s time to start identifying and removing the gaps of silence. Because of the amount of space I needed to save for this project, I accounted for gaps of silence starting at 10 milliseconds and greater. These gaps are identified and replaced with newly-created files called “Mutes,” which are just dummy, silent files of nearly the exact same length as the removed gaps. See below:

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(Dummy “Mutes”)

Like the Playlist Divider, the “_” at the beginning of the filename is used to keep the Mutes at the top of the REGIONS file list for easy access.

Side Note: When in the process of removing the silence, you have a couple options:

  • Use the “Strip Silence” edit tool. If unfamiliar with it, there is a great explanation of how that works here. In short, it’s a great way to remove silence en masse through automation. If you follow this route, you will need to take an additional step by highlighting the now empty space between files to determine what length of Mute to put in its place. See below:

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(“Strip Silence” applied and gap length identified)

  • If you want more control over editing individual sound files, select Pro Tools’ “Selector Tool.” You can then manually highlight and cut the silence and then replace it with Mutes.

Let’s take a look at an example of audio that was treated with this process. See below:

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(Original audio with gaps of silence)

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(Silence removed and replaced by Mutes)

For instances where more than 500 milliseconds of silence was removed, I stacked the Mutes contiguously to make up for the extra space (e.g. 500ms + 125ms). Accommodating for every instance of silence is time-consuming, so I find it easier to start with a basic palette of Mutes and build as needed.

This process is repeated until all files are complete, after which the edited files may look like this:

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This concludes Part 1. In Part 2, I continue looking for opportunities to save space by reusing audio clips in multiple places. Should you have any questions, please contact me via the social media links below or feel free to email me directly, [email protected]. Thanks for reading!

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