Measuring audio delay

Question

I am currently thinking about what I could do to measure the time it takes from the point where the computer gets audio input (through a normal audio input on a soundcard) to the point where there's something to work with, e.g. noise cancellation or something like that.

The main problem I reckon is to measure when the audio signal was created and the synchronization of the sender and receiver.

So far I came up with the following ideas:

• Use the serial port to transmit timing information
• Put a timestamp into the audio signal
• Transmit a recurring signal - a delay would be visible

Do you have more ideas or something that I m not seeing in mine? I thought I would find more academic work on this matter but was sad to see that this is not the case, am I searching wrong?

Answer 1

you can check the latency in windows with this tool they also have some great info on the site also you can read up on the ASIO drivers or try to reach out to the communities that use these tools (DJs Guitar modeling scene) another great source of information is open Source projects like JACK that have more technical information:

Latency Tool: http://www.thesycon.de/deu/latency_check.shtml

Asio Wikipedia Page: http://en.wikipedia.org/wiki/Audio_Stream_Input/Output

Guitar Amp Modeling: http://www.guitarampmodeling.com/

JACK Project homepage: http://jackaudio.org/

Hope that helps.