Create sound (voice) files for OpenTX with MacOS’ Siri in less than 1 minute

If you own an Apple Mac or MacBook and want to create your own quality voice sound files using macOS Siri voices – read on.

This is the final product:

General Information

There is an existing, vast and downloadable collection of OpenTX sound files called “OpenTX Soundpack Joanne“, which might be more than enough for most of us. But if you have specific tracks to record, it is fast and easy to do it yourself.

For sound files to run on OpenTX 2.2.x or later, the following OpenTX specs apply – this is just FYI:

• File Name: 123456.wav (up to 6 characters plus .wav)
• Sample Rate: 16 kHz
• Bits / Sample: 16
• Tracks: 1, mono
• Compression Codec: PCM (or u-law, a-law)

Don’t be put off by the technicality of those specs above. We will use a conversion website that will take care of all that.

First Step: Let’s have Siri produce the voice file

• Open the Terminal application on your mac (CMD + space, type terminal)
• in Terminal type cd desktop (cd = change directory), to make sure the sound files produced will be saved on your computer’s desktop.
• To produce a file with the name “a2roff” containing the sentence “ail to rudder, off” paste
  say -o “a2roff” “ail to rudder, off”
  into the terminal application. Paste the whole line including the quotation marks, press enter, and the voice file is created instantly. You won’t get any confirmation that the file was created. It’s just done. Check your desktop. The file will be called a2roff.aiff. We will convert that file to the OpenTX specifications in the second step.

You obviously can replace the file name and the sentence you want Siri to say to whatever you like. Small hint: If you add a “,” (comma) in the text, it will create a slight delay between the words.

Second Step: Convert the .aiff file to .wav using the OpenTX specs

• Go to https://audio.online-convert.com/convert-to-wav 
• Upload a2roff.aiff (or whatever your file is called) and convert it using these settings:

You’re done. Place that newly created sound file in the usual directory on your TX sd-card (E.g. SOUNDS/en/).

How to manage your sound files

To keep a record of the sound files created and to speed up the process, I use an Excel sheet that puts together the line to paste into Terminal based on my choice of file name and text I want Siri to speak. If interested, give me a shout. I am happy to share it. It looks like this:

If you want to create the Excel file yourself, the only tricky line is in column E, the formula is:

=B9&” “””&C9&””””&” “””&D9&”””” 

This formula combines the content of columns B, C and D in the proper format. Using this spreadsheet, all you need to do to produce a voice file is to copy the formula from column E into Terminal and press “enter”.