I experimented with various values. Another way to save time is the same idea but ... make a program that have a couple objects randomly tossed about - a few cubes.
For each cube, load and play a different "3d sound" may color cubes so you know what color should be playing what sound if you see it while moving about.
Oh...that moving about? Make your cam movable so you can fly around. After roating and positioning cam, make the listener in the same position rotation as cam.
Now... add to your program the ability to have a float viable to hold this SCLAELISTENER value, set up you program to display this value each loop and keypresses to adjust it on the fly realtime.
You should be able to experiment with type of set up.