Hi,
I have made my first experiment by using Matlab and the psychtoolbox. Thank you very much that you have made the psychtoolbox so awesome! :) But I have a bit of a problem now, to which I haven't found a solution yet, so I hope you could help me out.
I want to make sure that my visual and auditory stimuli are presented in exact synchrony. So I am using PsychPortAudio with an external usb ASIO soundcard. It works all fine, I am however still in doubt if the stimuli are presented in exact synchrony. I get a PTB message in matlab telling me the output and input latency before playing the sound. Does this mean that the latency that comes with my external usb soundcard is already corrected? (I don't really think that this is possible, but I still want to make sure.)
I did a latency test by using the program audacity and found out that my external soundcard has a latency of 234 milliseconds. (Which I think is rather high....) Should I let my auditory stimulus start 234 milliseconds earlier now?
The PTB message tells me however that I have an output and input latency of about 400 milliseconds. How is that possible? How does PTB compute these latencies?
Do you have any tips on how I can make sure that my visual and auditory stimuli are presented in exact synchrony?
Thank you in advance,
Angelique
I have made my first experiment by using Matlab and the psychtoolbox. Thank you very much that you have made the psychtoolbox so awesome! :) But I have a bit of a problem now, to which I haven't found a solution yet, so I hope you could help me out.
I want to make sure that my visual and auditory stimuli are presented in exact synchrony. So I am using PsychPortAudio with an external usb ASIO soundcard. It works all fine, I am however still in doubt if the stimuli are presented in exact synchrony. I get a PTB message in matlab telling me the output and input latency before playing the sound. Does this mean that the latency that comes with my external usb soundcard is already corrected? (I don't really think that this is possible, but I still want to make sure.)
I did a latency test by using the program audacity and found out that my external soundcard has a latency of 234 milliseconds. (Which I think is rather high....) Should I let my auditory stimulus start 234 milliseconds earlier now?
The PTB message tells me however that I have an output and input latency of about 400 milliseconds. How is that possible? How does PTB compute these latencies?
Do you have any tips on how I can make sure that my visual and auditory stimuli are presented in exact synchrony?
Thank you in advance,
Angelique