how to measure the sound latency?

[Michiel Sovijarvi-Spape]

Hi,
Just to add, in a geeky sort of way, that it of course also depends on the
distance to your speakers :) With the speed of sound being 343.2 m/s, the
time it takes to travel 0.5 m (in a classical setup) should be about 1.7 ms.
That's less than PST's self-proclaimed accuracy!
Best,
Mich

-----Original Message-----
From: e-prime at googlegroups.com [mailto:e-prime at googlegroups.com] On Behalf
Of David McFarlane
Sent: 07 May 2012 21:43
To: e-prime at googlegroups.com
Subject: Re: how to measure the sound latency?

HanGue,

Get an oscilloscope, a sound file with a sharp attack, and an E-Prime
computer with a simple digital output (e.g., a legacy parallel port).  Use
the E-Prime Onset/OffsetSignal facility to output a signal to the digital
I/O port at the onset of your SoundOut object (see, e.g.,
Slide.OnsetSignalEnabled in the E-Basic Help facility).

Hook up your oscilloscope input to the audio output of the EP computer, and
the oscilloscope trigger to the digital I/O port.  Now run your program to
see the latency between object onset and sound onset.

As I understand it, this is pretty much what PST did, except they used the
Black Box Tool Kit which allowed them to automate this test and rapidly
collect repeated samples.  Perhaps you could contact PST for details.

-----
David McFarlane
E-Prime training
online:  http://psychology.msu.edu/Workshops_Courses/eprime.aspx
Twitter:  @EPrimeMaster (twitter.com/EPrimeMaster)


At 5/7/2012 09:33 AM Monday, you wrote:
>Hallo,
>
>Is there a way to measure the sound latency?
>between the time when the E-Prime calls a sound to play and the time 
>when the sound actually emits from the soundcard or speaker.
>
>I want to give a sound feedback in a precise time after a button press
event.
>So, we used 'SoundBuffer Object' and played in InLine object.
>
>Just what I know is that i read from this site 
>(http://www.pstnet.com/eprimestartup.cfm).
>and download the soundtest file 
>(http://www.pstnet.com/support/kb.asp?TopicID=4348).
>there was no issue with this test
>
>Best,
>HanGue.

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