E-Prime Knowledge Base

4348 - INFO: Use of SoundTester to determine machine compatibility with ASIO or Core Audio/WASAPI

A sound startup latency is the amount of time that your computer processes sound from E-Prime before it was audible. If your experiment does not require a specific sound startup latency, just use your computer's current sound hardware and E-Prime's default DirectSound API. Sound will still be generated and the SoundTester does not need to be used in that case. However, if your sound quality is poor or you are aiming for optimal sound startup latency, SoundTester is recommended.

To achieve the most likelihood of low sound startup latency under Windows Vista and Windows 7 under E-Prime 2.0, several other considerations must be made in regards to which sound card, sound driver, and Windows API that will be best for you. For an explanation of these concepts and some results from our timing tests that can help with these decisions, please first read this article: INFO: Sound Latency - Not all sound cards provide optimal millisecond timing. Then, use the SoundTester application to determine the current capabilities of your data collection computers. The application is included with E-Prime 2.0.10.182 or higher.

The goal of using this program is to select the best API for your computer and obtain the lowest possible Buffer Duration that will still play sound within that API. Once this has been determined, a configuration file will be saved to your My Experiments folder that will be used by all runtime files that run on that computer. You will need to use the SoundTester to generate a configuration file for each computer that will be collecting data, as computers may differ.

Detail
Using SoundTester
1) When starting the SoundTester application, it will prompt to use the x86 or x64 native editions. PST encourages using the x86, even on x64 systems, since the x64 version should be used only at the request of a Technical Consultant.

2) Under the Devices area, a tree hierarchy of the three main API (ASIO, Core Audio, and DirectSound) are listed with potential sound devices for each API as child nodes in the tree. If an API does not have any child nodes under it, then audio outputs are not available for that API. This may be expected if you do not have hardware that is compatible with a specific API or you are running Sound Tester in Windows XP; however, it may also mean that a driver for that API is required. Please see the Obtaining Drivers section below. It is encouraged to check all nodes in the Devices listing to begin and then use the 44.1kHz and 48kHz samples to run through each device by selecting the radio button and then clicking the Run button to begin. PST does not encourage using the custom File option at this time unless directed by a Technical Consultant in a support request.

3) A prompt to begin the test will occur during the test run for each device, after which you may see a configuration screen depending on which API you are using. The first time you see this screen, you should keep the default Buffer Duration to make sure that the sound will play.

4) Then, the sample sound will play for about 3-5 seconds. While the sound plays, pay attention that it plays with no cracks, pops, or other issues. If sound does not play for one of the nodes, it most likely means that part of the device is not in use. For example, if you do not have headphones plugged in and the 'High Definition Audio Device (Headphones)' node does not play a sound, SoundTester is functioning correctly. If none of the nodes play for an API, a driver may be needed. Please see the Obtaining Drivers section below. In the event the application freezes or another fatal error occurs, then take note of which device caused the offending problem and rerun the test but with the checkbox next to the node in question unchecked to skip the test on subsequent runs.

5) After each sample is played, a prompt will ask if the sound played without a problem. SoundTester will record this answer in its log file.

6) You will then be prompted to Replay the sample. This gives you an opportunity to get back to the configuration screen quickly to try a different Buffer Duration value. It is suggested that you decrease this value each time until you reach a value that produces poor sound. Then, run the test one more time with the value that was used before the poor performance and answer 'Yes' to the 'without a problem' prompt, and 'No' to the 'Replay' prompt. You could also try any of the following special buffer size values:

ASIO
0 = Use driver preferred size (may be large!).
-1 = Use minimum size (lowest possible latency, higher chance of issues). This is the E-Prime default.
-2 = Use maximum size (lowest chance of problems, highest latency). This could be very high, possibly 100s of ms.

Core Audio
0 = Use driver preferred size
-1 = Use minimum size (lowest possible latency, higher chance of issues). This is the E-Prime default.

7) Finally, if you are satisfied with your results, click 'Yes' when asked to 'Save configuration for use by E-Prime?' to write the configuration file for each specific API to your My Experiments folder. You will then be shown the path to the separate log file for that session. By default, it will be in a folder called 'SoundTester' on your desktop.

Obtaining Drivers
In Windows 7, PST generally recommends on board sound with the default High Definition Audio Device driver and the Core Audio API. This means that you should not seek out any additional driver and use the driver provided by Windows automatically.
In Windows Vista, we recommend an add-on PCI or PCIe sound card with the manufacturer's driver and the Core Audio API. You may find this driver by running Windows Update. If not, check the manufacture's website.

Returning the report files
Each device test will create a log file under the Sound Tester folder on your desktop.
Please provide the results of the SoundTester application as an attachment to an e-mail to info@pstnet.com or a web support request so that a sound card/API compatibility table may be updated regularly in this article.

This topic was created on:
Updated on 11/10/2010 6:49:00 PM (GMT)

This topic was last updated on:
Updated on 8/16/2013 8:34:00 PM (GMT)



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