onset delay in slide with soundIn and picture

[Viqui]

Hi everyone, 

I want to record vocal responses for which wav files should start as soon as a picture is shown on the screen. In that way, my 0-ms would be perfectly aligned between picture presentation and wav file onset (so I can calculate vocal RTs manually offline).

I'm not an E-prime user, I'm doing this for the first time. 

Right now, I've embedded both the picture stimulus and the SoundIn into a slide. I'm getting reasonable to awful onset delays for different objects in my trial, but that's okay since I'm not recording any EEG, etc. along with it. I do however worry a lot about a potential lag between the picture stimulus onset and the start of my wav file. (First attempts were using DirectSound API, subsequent attempts with CoreAudio made onset delays even larger!)

Does anyone know whether the onset delay of my slide (with Picture and SoundIn objects) concerns the whole slide and only that, or should I be expecting asynchronous onset delays between picture and wav file? And in case you know the answer to this, is it gut feeling, have you derived it from E-prime's timing reports, or have you actually tested it with an external device, e.g., something with a photodiode producing sound so that you recorded both signals and analysed them yourself?

Thanks a lot for any feedback!

Vitória

[David McFarlane]

Vitória,

If you do not get an answer here, you might try asking PST Support. And
then please write back here with their response.

-- David McFarlane