Charles, whenever I hear someone say that they can or have learned the ability to tell alloyed gold apart from aluminum, by virtue of sounds, tones, smoothness, etc.... I challenge them: Meet me at a blighted junky park, and let's turn you loose. See how much gold you get, and how much aluminum you leave behind. EVEN if only a 1 in 50, or 1 in 100 ratio. And after you give them this challenge, you hear nothing but the sound of chirping crickets.
If ever a person digs a gold ring (after digging 50 foil and aluminum), yes, they will say to themselves: "Aha! That one sounded different!" (and then figure they can isolate and learn that sound). But this is nothing more than the trick of selective memory bias. Every time you and I stop to dig a signal, we're subconsciously thinking "this one sounds different". And after it turns out to be junk, we forget our premonitions. Or think "come to think of it, it *did* sound kind of junky". But when one FINALLY turns out to be gold, only THEN do we remember our premonitions and say "aha! I knew it".
JMHO
If ever a person digs a gold ring (after digging 50 foil and aluminum), yes, they will say to themselves: "Aha! That one sounded different!" (and then figure they can isolate and learn that sound). But this is nothing more than the trick of selective memory bias. Every time you and I stop to dig a signal, we're subconsciously thinking "this one sounds different". And after it turns out to be junk, we forget our premonitions. Or think "come to think of it, it *did* sound kind of junky". But when one FINALLY turns out to be gold, only THEN do we remember our premonitions and say "aha! I knew it".
JMHO