What is it?
Sound Out Preferences lets you choose how sounds will be played.

How to use it
Sound Out Preferences has the following six parameters, Use Mixer, Stereo Playback, Linear Interpolation, Rewind Speed, Fast Forward Speed, and Allow Background Tasks.

The Use Mixer check box when selected, plays sounds with mixing board control.  Same as the Mixer command in the Controls menu.

The Stereo Playback check box when selected, sounds are played in stereo no matter how many tracks they have.  Same as the Stereo command in the Controls menu.

The Linear Interpolation check box when selected, sounds are played with Linear Interpolation.  It improves sound quality but slows down the computer.  Same as the Linear Interpolation command in the Controls menu.

The Rewind popup menu has the choice of 10 different speeds for the Rewind command and the Shuttle.

The Fast Forward popup menu has the choice of 10 different speeds for the Fast Forward command and the Shuttle.

The Pan Delay Steps popup menu has the choice of 4 different ranges for the Mixer's Pan Delay.  1000th has a range of 1 to 31 milliseconds each step (pixel) being 1 millisecond.  2000th has a range of .5 to 15.5 milliseconds each step being 500 microseconds.  4000th has a range of .25 to 7.75 milliseconds each step being 250 microseconds.  8000th has a range of .125 to 3.875 milliseconds each step being 125 microseconds.  

The Background Tasks check box when selected, lets other programs run normally in the background when playing sounds (slower).

Notes  
The main reason you would want to turn off the Mixer, Stereo Playback, Linear Interpolation, or Background Tasks, is if the computer is having trouble playing multi-track sounds.