M-Audio 121002, 1010LT manual

MULTITRACK DRIVER DEVICES: The Delta 1010LT drivers intelligently synchronize the beginning of recording and playback across all audio devices on the board. When using application software that is capable of using multiple channels simultaneously, select "Single and In-Sync" to ensure that all audio channels will begin playback and/or recording at the same time. Otherwise select "Independent" to allow the audio channels to play independently

–this setting may be desirable if more than one application needs to access the Delta 1010LT simultaneously.

DMA BUFFER SIZES: This section specifies the amount of system memory dedicated to digital audio buffering. Setting a buffer size that is too small may result in clicks or pops in the audio stream as some data may be lost. Larger buffers cause slightly more latency but prevent the pops and clicks that might occur with smaller buffer sizes – the default settings are recommended but you may desire to tweak these default settings to suit your tastes. This buffer size must be set in the Delta Control Panel before you launch your music software. When using ASIO with the Delta 1010LT, set the buffer size in the control panel, then exit the control panel. After doing so, launch your music software.

SOUND MANAGER: The Hardware Settings Page in the Delta Control Panel also contains software switches that allow you to select which Delta input and output stereo pair will be used by the Sound Manager, if and when you choose the Delta as the Sound Manager input and output device. If you go to the Apple menu Control Panel Sounds and highlight the Delta icon for Sound In and Sound Out, then your Apple system sounds will be routed to the Delta hardware output that you have selected here, and Alert Sounds, if you choose to record, will receive their input from the Delta hardware input that you select here.

You will want to choose the Delta for input and output in the Sounds control panel if your music program does not use ASIO and the Delta ASIO drivers. If you are using the ASIO drivers (see Mac Software Installation), you may want to leave the Sounds control panel selection to “built-in.” With the Sounds control panel set to built-in, these Sound Manager settings in the Delta Control Panel will have no effect, and your system sounds will come from your internal sound card.

The Sound Manager driver limits you to using only one of the Delta 1010LT stereo input pairs for audio input and only one of the stereo output pairs for output. These do not need to be matched pairs- you can use inputs 1&2 for Sound In and S/PDIF for Sound Out, for example, or any combination that you choose. The following screen shot shows the Hardware Settings page on the Mac with the Sound Manager I/O set to “Analog 1&2” for Input and “Analog 1&2” for Output. Once you have made a selection, go to the File menu and “Save as Preferences.”