Jelli Noise

Scripted Automation of Sound Design Tasks for Radio

BY Adam Kay ON May 21, 2013 IN Jelli News

As audio engineers, we are frequently faced with performing extremely similar tasks in vast quantities.  Most seasoned engineers are adept at using batch processors to convert, level-balance or even add effects processing to files.Sample Manager and Sound Grinder are two excellent batch processing solutions that cut down on human error while saving time and sanity.

Here at Jelli, we take these concepts a step further by writing our own custom tools and workflows.  We not only convert and process files, but nearly every piece of audio produced week in and week out is created automatically via drag and drop.

While it might sound like we have a team of C++ programmers writing our own custom version of Pro Tools, it is really just me, a little bit of AppleScript and some basic knowledge of the command-line.

In this article, I’m going to show you a couple of our tools (just to give you an idea of what is possible) and also share with you some resources for building your own custom workflows.  If you are a technically inclined audio engineer, you should spend some time learning some of these technologies and building your own workflows.  If you are a creative producer, you should seriously consider contracting an engineer to help you build some custom tools.

Both of the examples shown here are primarily accomplished using AppleScript and an open-source command line audio editor called SoX (Sound eXchange).

For those of you looking to install SoX on your Mac, I highly recommend using the Homebrew package manager.  If you are working in Windows, fear not.  SoX is cross-platform.  Anything done here with AppleScript could be re-created using Batch scripting.

For a quick-start guide on using SoX, you should check out 15 Awesome Examples to Manipulate Audio Files Using SoX and also, my own notes from a talk I gave at the Game Developer’s Conference in 2011, Work Smarter, Not Harder: Automating Repetitive Tasks During Audio Content Creation.


Twice weekly, I browse through messages left by Jelli listeners at 888-YO-JELLI, and select a few shout-outs to play on the air.  The first thing I have to do is manually trim the file to get rid of any unwanted noises at the head or tail.  But, once I’ve done that, I simply drag the file to my AppleScript and it spits out a fully mixed file, mastered, encoded and named so that it is ready for upload to our servers.

My AppleScript utilizes SoX, which determines the length of the voicemail file, while simultaneously measuring and adjusting its level.  It then sequences the voicemail sample with an intro and outro samples (pulled from a pool of available samples, for variation).

User of the Week
Every Friday, we announce the Jelli User of the Week, aka the user with the most voting activity on Jelli.  This audio imaging, which is exactly 1 minute in length, is comprised of the username, an example sigTone and a handful of shout-outs filling out the remainder of our time.  This is all stitched together on top of a couple of music elements with some pre-recorded voiceover in between.

Again, Applescript and SoX are used.  I drop the username and sigTone files onto my AppleScript, which works with SoX to stitch together the announcement bits.  It then combs through all of my most recent shout-outs (archived using the Shout-Outs script above) and finds the right amount to fill the remaining space in the minute.




The end result is that I spend substantially less time importing, mixing, bouncing and labeling files.  What would normally take me an hour to accomplish in Pro Tools is completed with a couple of quick snips in a two-track editor and some dragging and dropping.  Time is saved, human error is substantially reduced and everything perfectly adheres to our naming conventions and file format standards.

Now, I am not suggesting we do away with Digital Audio Workstations. Far from it. I am a Pro Tools user and I still use it regularly. No amount of scripting can replace the thousands of creative choices that go into designing an audio sequence from scratch. However, there is no need to design it from scratch each and every time.  After the creative groundwork has been laid, a little scripting can go a long way in making your life a little easier.


Useful Links
SoX SourceForge page – The SoX homepage
AppleScript Language Guide – Apple’s own guide to using AppleScript
Work Smarter, Not Harder: Automating Repetitive Tasks During Audio Content Creation – My notes from a talk I gave at the Game Developer’s Conference in 2011
15 Awesome Examples to Manipulate Audio Files Using SoX – Some quick and easy SoX commands to try

Adam Kay

Adam Kay

sr software engineer