I wanted to mention that if you pay close attention to the visual display of that scanner, you will soon start being able to pick out specific types of outcrops, meteorites etc just based on what the lines on the scanner look like and how they are behaving.
No doubt, having the sound accompany these scanner displays would be an immense help, but I have learned over time to use that scanner pretty effectively by just using the visual cues.
Yeah I don't have trouble with the other sources but these three (geyser, piceous cobble and volcano) I just can't seem to find. Every time I think I got one, as I get closer, the scanner signal resolves itself or turns out to be one of the ones I don't want.