I will tell you an example of something that I know for sure to get an idea.
I believe that the gold gun has the ability to separate between different materials.Sound compared to meter readings can give you discrimination.
There are people that mastered it through practice.The designer and the maker just put down the idea and they never bothered testing it properly.
Here is an example of what has been found out from some users and I can verify it as well.
Whenever you point the Goldgun to a place that pieces of ceramics are burried you will have always the same sound coming out of it.
It is like having a very hot piece of metal putting it inside a pan full of water.You hear a sound that lasts as long as it takes for the metal to cool down and it has always the same characteristics.
It starts loud and sharp and it goes off gradually, usually it takes 1-2secs for the whole sound to dissapear.
