[Python] Timing jitter between audio stimulus and eeg maker using parallel ports PsychoPy

I am sorry for reposting this request here (as I already posted it on the psychopy forum (https://discourse.psychopy.org/t/ti...ulus-and-eeg-maker-using-parallel-ports/44387), however I am under severe time pressure and in need for quick help...

OS (e.g. Win10): Win10 PsychoPy version (e.g. 2024.2.4 Py 3.8): 2024.2.4 Standard Standalone Installation? (y/n) If not then what?: y Do you want it to also run online? (y/n) n What are you trying to achieve?: Send a parallel port marker for an audio stimulus

What did you try to make it work?: After having massiv jitter (+/-15ms and more) in my main experiment I created a ‘bearbone’ experiment in the builder with only a parallel port and a audio stimulus. I also created similar set ups with code components and ‘pure’ code. I also used different settings (e.g. sync to screen, samplerate, …). I use th ptb backend as all other backend fail to work (altough being explicitly installed)

Link to the most relevant existing thread you have found: https://discourse.psychopy.org/t/inability-to-have-precise-timing-for-auditory-stimuli/34031

What specifically went wrong when you tried that?: The experiment runs without problems however, when comparing the true onset of the sound and the marker there is a lag of ~5ms (as promised by PsychoPy’s website) BUT also a massiv jitter of about ~10ms or more (depending on settings).

I am really under time pressure and would appreciate a speedy response!

Thank you!

Tim

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