Sound Startup Latency Tests


E-Prime reports millisecond accurate timing. This does not mean that E-Prime is capable of making hardware do things it cannot. For experiment paradigms that require auditory stimuli, much care and concern should be considered with the hardware being used. Sound cards can have good or poor startup latency, which is the time from when E-Prime tells the sound card to play sound to when the sound actually emits from the sound card or speakers. Not all sound cards are created equal. Results can also depend on the selected sound card driver and selected API (application programming interface). The default API used by Windows XP and E-Prime 1.0, E-Prime 1.1, E-Prime 1.2, and E-Prime 2.0 is DirectSound, which is the capabilities offered by DirectX. E-Prime 2.0.10.X allows for the option of selecting the DirectSound, ASIO or CoreAudio/WASAPI APIs so that the API with the lowest possible sound latency for a particular sound card may be used.

For more information on APIs in Windows Vista and 7, please see this article: INFO: Sound Latency - Windows Vista / Windows 7 (and beyond). To determine the best API for your hardware, please see the chart below or use our Sound Tester program as detailed in this article: INFO: Use of SoundTester to determine machine compatibility with ASIO or CoreAudio/WASAP API. Also, note that if the DirectSound sound startup latencies reported below are acceptable for a specific paradigm, the E-Prime experiment's Sound device will not need to be configured or changed and the defaults may be used.

PST encourages using external equipment to determine the startup latency of your sound card. For our tests, we collected data using a Black Box Toolkit (BBTK) connected to a HP ZD7000 laptop. For more information on the BBTK, please visit their website at http://www.blackboxtoolkit.com/. Each experiment computer generated a sound as well as a parallel port pulse that was detected by the BBTK's microphone and line in respectively. All sounds were sent through the same Altec Lansing VS2620 speakers. There were a total of 18 sounds and port pulses collected for each session. The experiment paradigm used white noise files that were set to 2 channels, 16 bit, and 44.1Khz. The parallel port pulse was sent at the start of the SoundOut object in the experiment paradigm. Since parallel port pulses have been shown to have extremely low latency, the receipt of this pulse represented the time that the sound was sent from E-Prime to Windows for processing. This was compared to the time that the BBTK received the sound through the experiment computer's speakers. The difference in these two times represented the sound startup latency, that is, the amount of time that Windows, the sound card, and the speakers processed the sound before it was audible.

As a result of our tests for Windows 7, PST generally recommends on board sound with the default High Definition Audio Device driver and the CoreAudio API. In Windows Vista, we recommend an add-on PCI or PCIe sound card with the manufacturer's driver and the CoreAudio API. For Windows XP, on board sound was found to be comparable to some add-on cards.



New E-Prime 2.0 Sound Card Startup Latency Results

Adapter Type Machine Operating System Driver API/Expected Latency Mean (ms) StdDev Min (ms) Max (ms)
On Board n/a Ad Hoc Quad Core 7x64 HDAudio DirectSound 40.733 4.217 34.000 49.000
On Board n/a Ad Hoc Quad Core 7x64 HDAudio CoreAudio 3ms 5.533 1.060 4.000 7.000
On Board n/a Ad Hoc Quad Core 7x64 HDAudio ASIO4ALL 4ms 6.071 0.616 5.000 7.000
Sound Blaster SB0880 X-Fi PCIe Ad Hoc Quad Core 7x64 HDAudio DirectSound 55.000 5.306 50.000 71.000
Sound Blaster SB0880 X-Fi PCIe Ad Hoc Quad Core 7x64 HDAudio CoreAudio 3ms 3.643 1.008 2.000 5.000
Sound Blaster SB0880 X-Fi PCIe Ad Hoc Quad Core 7x64 manufacturer DirectSound 344.267 830.216 119.000 3345.000
Sound Blaster SB0880 X-Fi PCIe Ad Hoc Quad Core 7x64 manufacturer CoreAudio 3ms 28.214 3.017 23.000 32.000
Sound Blaster SB0880 X-Fi PCIe Ad Hoc Quad Core 7x64 manufacturer ASIO4ALL 4ms 16.714 0.611 16.000 18.000
Sound Blaster SB0790 X-Fi PCI Ad Hoc Quad Core 7x64 manufacturer DirectSound 142.200 12.359 134.000 186.000
Sound Blaster SB0790 X-Fi PCI Ad Hoc Quad Core 7x64 manufacturer CoreAudio 3ms 18.600 3.043 15.000 23.000
Sound Blaster SB0790 X-Fi PCI Ad Hoc Quad Core 7x64 manufacturer ASIO4ALL 4ms 357.143 0.864 356.000 359.000
Asus Xonar DG PCI Ad Hoc Quad Core 7x64 manufacturer DirectSound 69.643 1.277 68.000 72.000
Asus Xonar DG PCI Ad Hoc Quad Core 7x64 manufacturer CoreAudio 3ms 26.400 2.063 23.000 29.000
Asus Xonar DG PCI Ad Hoc Quad Core 7x64 manufacturer ASIO4ALL 4ms 367.786 0.802 366.000 369.000
HT Omega Striker 7.1 PCI Ad Hoc Quad Core 7x64 manufacturer DirectSound 88.071 3.025 83.000 93.000
HT Omega Striker 7.1 PCI Ad Hoc Quad Core 7x64 manufacturer CoreAudio 3ms 25.071 1.685 23.000 28.000
HT Omega Striker 7.1 PCI Ad Hoc Quad Core 7x64 manufacturer ASIO4ALL 4ms 366.714 0.914 365.000 368.000
On Board n/a Dell Precision T3400 7x64 HDAudio DirectSound 44.714 8.416 35.000 70.000
On Board n/a Dell Precision T3400 7x64 HDAudio CoreAudio 3ms 8.214 1.122 7.000 10.000
On Board n/a Dell Precision T3400 7x64 HDAudio ASIO4ALL 4ms 6.643 0.929 5.000 8.000
On Board n/a HP Pavilion dv7t-1000 laptop 7x64 HDAudio DirectSound 47.357 3.795 43.000 53.000
On Board n/a HP Pavilion dv7t-1000 laptop 7x64 HDAudio CoreAudio 3ms 6.214 1.051 5.000 8.000
On Board n/a HP Pavilion dv7t-1000 laptop 7x64 HDAudio ASIO4ALL 4ms 6.267 0.458 6.000 7.000

 

Adapter Type Machine Operating System Driver API/Expected Latency Mean (ms) StdDev Min (ms) Max (ms)
On Board n/a Ad Hoc Quad Core Vista x86 HDAudio DirectSound 58.400 7.278 53.000 83.000
On Board n/a Ad Hoc Quad Core Vista x86 HDAudio CoreAudio unusable
On Board n/a Ad Hoc Quad Core Vista x86 HDAudio ASIO4ALL 4ms 19.786 2.806 15.000 24.000
Sound Blaster SB0880 X-Fi PCIe Ad Hoc Quad Core Vista x86 HDAudio DirectSound 58.933 5.535 53.000 76.000
Sound Blaster SB0880 X-Fi PCIe Ad Hoc Quad Core Vista x86 HDAudio CoreAudio 90ms 136.357 29.705 92.000 177.000
Sound Blaster SB0880 X-Fi PCIe Ad Hoc Quad Core Vista x86 HDAudio ASIO4ALL 4ms unusable
Sound Blaster SB0880 X-Fi PCIe Ad Hoc Quad Core Vista x86 manufacturer DirectSound 129.667 24.307 120.000 217.000
Sound Blaster SB0880 X-Fi PCIe Ad Hoc Quad Core Vista x86 manufacturer CoreAudio 3ms 26.800 3.509 22.000 32.000
Sound Blaster SB0880 X-Fi PCIe Ad Hoc Quad Core Vista x86 manufacturer ASIO4ALL 4ms 17.286 0.611 16.000 18.000
Asus Xonar DG PCI Ad Hoc Quad Core Vista x86 manufacturer DirectSound 69.200 1.146 68.000 72.000
Asus Xonar DG PCI Ad Hoc Quad Core Vista x86 manufacturer CoreAudio 3ms 26.867 1.685 24.000 30.000
Asus Xonar DG PCI Ad Hoc Quad Core Vista x86 manufacturer ASIO4ALL 4ms 367.000 0.756 366.000 368.000

 

Adapter Type Machine Operating System Driver API/Expected Latency Mean (ms) StdDev Min (ms) Max (ms)
On Board n/a Ad Hoc Quad Core XP x86 default DirectSound 29.400 0.986 27.000 31.000
Sound Blaster SB0880 X-Fi PCIe Ad Hoc Quad Core XP x86 manufacturer DirectSound 11.667 0.488 11.000 12.000
Asus Xonar DG PCI Ad Hoc Quad Core XP x86 manufacturer DirectSound 69.133 1.642 67.000 72.000

 

 

E-Prime Legacy (Version 1.2) Sound Card Startup Latency Results

Adapter

Type

Machine

Operating System

Mean (ms)

StdDev

Min (ms)

Max (ms)

Sound Blaster 128

PCI

Dell 8200 Desktop (2.2 GHZ)

Windows XP SP2

6.708

2.116

1.000

9.000

Sound Blaster Live!

PCI

Dell 8200 Desktop (2.2 GHZ)

Windows XP SP2

2.042

0.204

2.000

3.000

Sound Blaster Audigy 2

PCI

Dell 8200 Desktop (2.2 GHZ)

Windows XP SP2

2.500

0.590

2.000

4.000

Sound Blaster Live! 24 External

USB

Dell 8200 Desktop (2.2 GHZ)

Windows XP SP2

10.208

2.146

7.000

14.000

Turtle Beach Santa Cruz

PCI

Dell 8200 Desktop (2.2 GHZ)

Windows XP SP2

3.083

0.408

3.000

5.000

Avance Logic AW200

PCI

Dell 8200 Desktop (2.2 GHZ)

Windows XP SP2

7.667

1.274

6.000

12.000

Yamaha Xwave A571-T20 ESS Allegro

PCI

Dell 8200 Desktop (2.2 GHZ)

Windows XP SP2

12.792

3.189

7.000

16.000

Sound Blaster Ensoniq

PCI

Dell 8200 Desktop (2.2 GHZ)

Windows XP SP2

4.875

3.803

1.000

16.000

Sound Blaster Audigy2 PCMCIA

PCMCIA (Laptop)

HP ZD7000 2.8GHZ

Windows XP SP2

3.333

0.482

3.000

4.000

Conexant AMC Audio

Motherboard Chipset

HP ZD7000 2.8GHZ

Windows XP SP2

18.000

0.000

18.000

18.000


Paradigm

The paradigm used on the E-Prime side was the SoundExperimentStation.es file. The sound devices were set at 2 channels, 16 bit, 44.1Khz. A white noise sound file was used. Event generation file used on the BBTK The results are from 24 trials per subject/session.


Equipment


  • E-Prime 1.2.1.841 was used.
  • The E-Prime desktop computer was a Dell 8200 Desktop (2.2 GHZ).
  • 2.2 GHZ machine running Windows XP SP2.
  • The E-Prime laptop computer was an HP ZD7000.
  • 2.8 GHZ machine running Windows XP SP2.
  • The BBTK computer was an HP ZD7000.
  • 3.0 GHZ machine running Windows XP SP2.
  • Hyperthreading was turned on all computers.
  • The MSCONFIG diagnostic mode was used to shut down background applications and services.

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