I found three different "points" where my perception changes. The first is, when moving left to right one notch at a time, I hear it on change on the 9th notch

I found three different "points" where my perception changes. The first is, when moving left to right one notch at a time, I hear it on change on the 9th notch (1-based numbering starting with LAUREL notch as 1). If I start from right to left, I hear it switch on the middle notch. And finally, if I leave it on the 8th notch, I can hear both ways at the same time and also 'force' myself to hear one or the other. Additionally, I can make it sound like "larry", "gary", "yally" and a bunch of other things on various notches without much effort, like all those 'ghost hunting' shows and their EVPs that sound like whatever the plot needs...