Measuring the Audio Latency
Hello,
I'd like to measure the Audio Latency of a beep tone on my device while running Expyriment and I'd like to know what the software you used on the description in this page is: https://docs.expyriment.org/Timing.html
Additionally and just to confirm: in this description (Audio section), the latency measured refers to a sound played in Expyriment, doesn't it?
Thank you in advance.
Best,
Ana Luísa
Comments
Hi there,
unfortunately you cannot measure this purely with software (as there is no way for software to know when the actual sound was played).
For our tests, we hence used a hardware oscilloscope to measure audio latency. The exact model I cannot remember right now, but should be mentioned in our 2014 article (https://link.springer.com/article/10.3758/s13428-013-0390-6). Basically, the audio output of the computer was connected to the oscilloscope and in addition we sent a marker to the oscilloscope via a serial port.
With "latency" we mean the difference between the sent marker and the audio. That is, the difference between us telling the soundcard to produce a sound, and the sound actually arriving at the audio output of the computer.
Some people also have good experiences using a BlackBox toolkit (see for instance this recent thread: https://forum.cogsci.nl/discussion/7945/timing-of-expyriment-it-is-pretty-good).
I hope this helped. Let me know if you have more questions.
Best,
Florian
Hello Florian,
Thank you very much for your feedback and references. I am going to try to assess the timing accuracy of my audio events with an oscilloscope as described in the paper. Nevertheless, I didn't understand what type of marker you sent to the oscilloscope. Could you clarify that?
Thank you very much once again.
Best,
Ana Luísa