Audio engine enhancements

SONAR has several enhancements for audio device compatibility in WDM and WASAPI mode.

Improved consumer audio support

SONAR provides optimized support for onboard audio devices (internal sound cards) for desktop and laptop computers using either WDM or WASAPI driver modes, and provides more stable low latency playback and recording with all available sample rates and buffer sizes.

WASAPI audio driver enhancements

WASAPI (Windows Audio Streaming API) is the multimedia API from Microsoft. SONAR offers two WASAPI driver modes:

Exclusive mode. WASAPI Exclusive mode provides the lowest possible latency audio and direct access to the audio driver, bypassing the Windows audio engine. Only one application can access the driver in Exclusive mode.

Shared mode. WASAPI Shared mode allows multiple applications to access the audio driver. Windows will mix the audio output from SONAR along with audio from other apps such as YouTube.

Low latency audio for Windows 10

SONAR provides support for the Windows 10 low latency in WASAPI Shared mode, which can be selected via a new driver mode under Edit > Preferences > Audio - Playback and Recording.

When WASAPI Shared is selected, Windows will mix the audio output from SONAR along with audio from other applications. An advantage of Windows 10 is that WASAPI Shared mode now supports low latency playback and recording at buffer sizes down to 2 milliseconds.

Enable/disable built-in DSP

In Windows 10, WASAPI Shared mode has support for configuring built-in signal processing for inputs and output independently. Many onboard audio devices have built in DSP, such as Dolby audio enhancement of audio outputs and noise reduction for audio inputs. While these effects may be desirable for better quality audio from laptops (for example, for noise gating of microphone inputs), the DSP processing of these effects can cause latency.

SONAR allows you to enable or disable DSP effects on inputs and output devices in WASAPI Shared mode. This is done via the EnableWasapiDSP variable in Aud.ini. By default, SONAR enables endpoint DSP effects for input devices (for noise removal).

To configure the built-in signal processing for inputs and outputs:

1.	Go to Edit > Preferences > Audio - Configuration File.

2.	Under Configuration Settings, click Edit Config File.

The Aud.ini file opens in the default Windows text editor.

3.	In Aud.ini, add a new entry called EnableWasapiDSP in the [Wave] section, and set its value to the minimum desired buffer sample value. For example:

[Wave]

EnableWasapiDSP=0

Valid values are as follows:

0 = Disable all signal processing for inputs and outputs (RAW mode)

1 = Enable signal processing for inputs (default)

2 = Enable signal processing for outputs

3 = Enable signal processing for inputs and outputs

4.	Save Aud.ini and close the Windows text editor.

5.	Click Reload Config Settings to reload the current audio configuration settings from Aud.ini.

 

Note: Setting the EnableWasapiDSP variable to 2 or 3 will result in a minimum latency of 5 milliseconds in SONAR when using WASAPI Shared mode.

Support for single endpoint devices

SONAR’s enhanced WASAPI driver support allows you to use single endpoint devices such as USB microphones, Rocksmith Real Tone guitar cables, and USB speakers and headphones. For example, you can connect a Rocksmith guitar cable and a USB microphone and play through your onboard audio device or through USB headphones or speakers. This works at a latency of about 10 milliseconds in WASAPI Shared mode, and as low as 3 milliseconds in WASAPI Exclusive mode, which is very usable for tracking and playing virtual instruments.

Support for Bluetooth audio devices

SONAR supports output to Bluetooth audio devices such as Bluetooth headphones and speakers. Note that latencies are typically higher with such devices.

The following table shows how the new audio engine enhancements are supported in different versions of Windows.

 

	Windows 7	Windows 8	Windows 10
WASAPI Shared mode	Yes	Yes	Yes
WASAPI Shared mode latency	10 ms (fixed)	10 ms (fixed)	2-10 ms
WASAPI Exclusive Mode latency	Varies	Varies	min 2 ms
WASAPI endpoint DSP disable	No	No	Yes

 

See:

Audio - Playback and Recording

Improving audio performance

AUD.INI

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