Setting up USB Audio in Windows 7/Vista
In Windows 7/Vista, the underlying audio architecture has been completely redesigned and requires a different output mode from Windows XP in order to achieve bit-transparency. We recommend setting the media player to the WASAPI exclusive mode, which gives the audio stream the most direct path to the hardware.
For bit-transparent playback, regardless of the media player you are using, please be sure to:
- Set the software volume control to the maximum (0.0 dB).
- Turn off automatic gain adjustments, such as replay gain.
- Disable all DSP plugins.
- Ensure that CPU-intensive applications are not running since they may interrupt the streaming of audio data.
- Set power management to High Performance.
An idiosyncrasy in Windows 7/Vista can cause the power management to interfere with audio streaming and hog CPU resources. To avoid this potential issue, go to Control Panel → Hardware and Sound → Power Options, and select High Performance.
Bit Error Rate Measurement
Though there are several media players suitable for audiophiles using Windows 7/Vista, it's important to set them up correctly and verify their bit-transparency. Listening tests may give a hint of imperfections, but we simply cannot be sure until we measure the bit error rate.
We've selected two of the popular ones for bit transparency measurements – JRiver Media Center and foobar2000 – and thoroughly tested them using a pseudo-random digital sequence that exercises a wide range of levels and frequencies. We've performed the tests for all combinations of standard sample rates (44.1K, 48K, 88.2K, 96K, 176.4K, 192KHz) and bits (16 and 24). An example of such a measurement is shown below, performed on 24-bit, 192KHz data (0 % error rate means that the bits are completely unaltered) :
Setting up JRiver Media Center
With the built-in WASAPI exclusive mode support, setting up JRiver Media Center for bit-perfect playback is straight forward. The following steps will ensure that the audio stream from your computer will be passed on unaltered to the DAC.
- Go to Player → Playback Options, and select "WASAPI" for the output mode.
- Click on "Output mode settings" and make sure that "ANEDIO USB Audio" is selected for the device and "Open device for exclusive access" is checked.
- Click on "DSP and output format", and make sure that all signal processing is checked off and resampling is disabled.
Setting up foobar2000
- Download the WASAPI output support from the foobar2000 components page.
- Go to File → Preferences → Components, and click the Install button and find the file "foo_out_wasapi.dll" in the download directory. Upon installation, you should see "WASAPI output support" as shown below:
- Go to File → Preferences → Output, and select "WASAPI: Speakers (ANEDIO USB Audio)" as the output device.
- Once again, ensure that all signal processing, such as replay gain, is turned off.
