Windows WDM system audio is typically used for audio I/O in media players, web browsers, and similar programs, while ASIO is typically used for audio I/O in DAW programs. WDM and ASIO are different subsystems that are configured separately.
To ensure proper audio system functionality, follow these guidelines when using a Thunderbolt Apollo as the audio input and/or output device for Windows WDM system audio.
- ASIO and WDM sample rates must match. All sample rate values in ASIO DAW programs and WDM audio programs must be set to the same sample rate. If the ASIO and WDM sample rates are not the same, audio from one or more programs will not be heard correctly.
- When changing WDM sample rates: Set the sample rate in the Apollo Console Settings>Hardware panel before changing sample rates in the Sound>Playback or Sound>Recording control panels within Windows. Note that WDM programs may need to be closed then reopened to be heard correctly if the sample rate is changed in the Sound control panel within Windows.
- When changing ASIO sample rates: If the DAW sample rate is changed, WDM audio will no longer be heard correctly because the sample rates no longer match. In this case, the WDM sample rate must be changed in the Windows Sound>Playback panel to match the DAW sample rate.
- For optimum performance, a buffer size of 512 or lower is recommended when using Apollo for WDM system audio.
- If using Avid Pro Tools, it is not recommended to have Apollo set as the WDM input or output device for system audio while Pro Tools is in use.
- If an audio program has the option of using either ASIO or WDM, using the ASIO option is recommended for optimum performance.
- WDM system settings are configured in the Sound control panel within Windows. ASIO system settings are configured in the Apollo Console Settings>Hardware panel and within the DAW preferences.