VoiceXP gives users the ability to use MP3 files as responses to questions and statements. We can do this by using SSML to play an MP3. But the MP3 needs to meet some specific requirements in order to work.
The documentation below explains how to format an MP3 for use in responses. We recommend using the software Audacity, which is free and open-source.
Step 1) Record a standard MP3 or .wav file and open your existing audio file in Audacity, or record a new one in Audacity.
Step 2) At the bottom of the Audacity windows set the Project Rate (Hz) to 16000.
Step 3) Double click on your audio track inside of Audacity to select it, then go to Effect -> Amplify.
Step 4) Set the Amplification (dB) level to -16. You can ignore the New Peak Amplitude (dB)
Step 5) Go to File -> Export -> Export as MP3.
Step 6) Set the Bit Rate Mode to constant (bottom right of picture), then select the 48 Kbps preset under Quality.
Save your file to your computer and it is now ready for use in your skill.
Step 7) To use it in your skill, just select Play MP3 as a response, and then upload the MP3 you saved through this process.