PsychoPy Voicekey

Hi,

I am programming a word-naming experiment in which I want to use the voice key to detect the word onset. I was wondering what property of the speech signal is used to detect the onset. The
SimpleThresholdVoiceKey is based on loudness (trips if the current
chunk’s audio power > 10 * baseline loudness. In the code also something is mentioned about the VoicelessPlosiveVoiceKey: “See SimpleThresholdVoiceKey for a minimal usage example, or
VoicelessPlosiveVoiceKey for a more involved one.”. However, I cannot find this VoicelessPlosiveVoiceKey anywhere in the file.

Do you know where I can find this piece of code?

Best,
Ferdy