I noticed in the PsychoPy2 paper from this year the following paragraph:
A current limitation of temporal stimulus accuracy and precision, however, is the presentation of sound stimuli. There can be a lag (i.e., impaired accuracy) of sound onset, potentially up to tens of milliseconds, with associated trial-to-trial variability in those times of onset. Sound presentation relies on one of several underlying third-party sound libraries, and performance can vary across operating systems and sound hardware. The authors are currently conducting objective testing of performance across all these factors and updating PsychoPy’s sound library to one with better performance.
I was wondering if this also applies to recording response time to someone’s voice (voice key). @auriga it looks like you’ve posted on a somewhat related topic!