BackgroundAt the Black Box ToolKit we specialize in helping you achieve millisecond accurate presentation, synchronization, and response timing in your computer-based psychology experiments. Here are just a few of the things that can stop you doing just that!
- TFT Input lag
- TFT response time
- Image intensity
- Sound card latency
- Response devices
- Voice keys
- 3rd party equipment
- OS issues
- Software settings
- Conditional biases
- The laws of physics
Need more help?If you are unsure of how our products could work for you take a look at our What, Why and How pages. Answers to common application questions can be found in the FAQ section.
If you have an application in mind but aren't sure, feel free to get in touch via email. Alternatively contact us by mail, phone or fax. We are here to help!
Sound card start-up latency in psychology experiments
Soundcard start-up latency is the time it takes from telling the computer to play a sound to when the sound actually comes out of the speakers or headphones. Professional musicians have to deal with such issues regularly and a lag over a few milliseconds is considered unacceptable to the trained human ear. Empirical tests have shown that soundcards used in typical computer-based psychology experiment can have start-up latencies in the hundreds of milliseconds. This can make presentation timing and synchronicity with other equipment a real issue.
For example, Psychology Software Tools (PST) the authors of E-Prime have conducted tests where soundcard start-up latencies were anywhere between a few milliseconds to over 350 milliseconds (and in one case over three seconds!). This is in no way the fault of E-Prime but rather the hardware and operating systems used.
To compound the problem newer operating systems are actually worse than older ones. In the PST tests Windows XP did not have any soundcards with a start-up latency over 20 milliseconds. Windows Vista was averaged over 50 milliseconds and Windows 7 well into the 100's of milliseconds of lag. An excerpt from PST's results is shown below to illustrate the startling range of variation.
|Adapter||Type||Machine||Operating System||Driver||API/Expected Latency||Mean (ms)|| Std
|Min (ms)||Max (ms)|
|Sound Blaster SB0880 X-Fi||PCIe||Ad Hoc Quad Core||Win 7x64||Manufacturer||DirectSound||344.267||830.216||119.000||3345.000|
|Asus Xonar DG||PCI||Ad Hoc Quad Core||Win 7x64||Manufacturer||DirectSound||69.643||1.277||68.000||72.000|
Excerpt from PST's research on soundcard start-up latency
You are advised to view PST's full results and watch the video below explaining more about soundcard start-up latency.
Note how in the video a 7 year old soundcard out performs a newer model which is integrated into the motherboard!
A professional DJ shows you what start-up latency is with a practical demo of on-board sound versus
a dedicated soundcard.
a dedicated soundcard.