PsychPortAudioTimingTest([exactstart=1] [, deviceid=-1] [, latbias=0] [, waitframes=1] [,useDPixx=0])
Test script for sound onset timing reliability and sound onset
latency of the
PsychPortAudio sound driver.
This script configures the driver for low latency and high timing
precision, then executes ten trials where it tries to emit a beep sound,
starting in exact sync to a black-white transition on the display.
You'll need measurement equipment to use this: A photo-diode attached to
the top-left corner of your CRT display, a microphone attached to your
speakers, some oszillograph to record and measure the signals from the
diode and microphone.
Some parameters may need tweaking. Make sure you got the special driver
plugin as described in 'help
InitializePsychSound' for best results.
This is early alpha code, expect some rough edges...
'exactstart' = 0 -- Start immediately, measure absolute latency.
= 1 -- Test accuracy of scheduled sound onset. (Default)
'deviceid' = -1 -- Auto-select optimal device (Default).
'latbias' = Hardware inherent latency bias. To be determined by
measurement - allows to PA to correct for it if provided.
Unit is seconds. Defaults to zero.
'waitframes' = Time to wait (in video refresh intervals) before emitting beep + flash.
Defaults to a value of 1, may need to be set higher for
high latency sound hardware (where absolute latency > 1
video refresh duration).
'useDPixx' = 1 -- Use
DataPixx device to automatically measure the true
audio onset time wrt. to visual stimulus onset.
0 -- Don't use
DataPixx. This is the default.
Psychtoolbox/PsychTests/PsychPortAudioTimingTest.m