ASIO (Audio Stream Input Output) is Steinberg's standard for implementing audio input/output in the computer. The major advantage of ASIO with respect to Direct Sound is that ASIO supports multichannel audio input/output (DirectSound can be compared to a software mixer from which you can only hear the two stereo outputs). If the audio card in your computer has multiple (more that two) audio input/output(s), it probably supports the ASIO standard. Tip: for a list of cards that support ASIO, please click in the following web site: service.steinberg.de/knowledge.nsf/show/list_audiocards.

Important: Unity supports the ASIO standard only when running under Windows 98 (Windows 95 does not support some of the multithread calls needed to implement the loading of files within ASIO). Make sure the ASIO drivers are correctly installed by following the hardware installation instructions that come with the card or with the downloaded update drivers. Tip: for more information about ASIO, please go to (or click the hyperlink) steinberg.net/products/vst/asio.html.

The Unity DS-1 Control Panel includes options for the user to select the Unity Engine to run under the Direct Sound or the ASIO audio output drivers. Under ASIO, Unity provides three different output options:

Stereo, which provides a global stereo output corresponding to the mix of up to 16 MIDI channels Unity is executing.

Individual Mono, which provides up to eight individual mono outputs corresponding to MIDI channels 1 through 8.

Individual Stereo, which provides up to four individual stereo outputs corresponding to MIDI channels 1 through 4.

Important: ASIO drivers may use all available channels when running Unity, failing to provide additional wave audio support. In this case, you will need to have another audio card, selected in the Multimedia Control Panel as the Preferred Audio Device, to be able to audition samples from the Unity DS-1 Editor application.