Though pulse machines lack 'discrimination',
after getting some hours in, you can have some idea of what's there from subtle tone differences,
here's a few for Whites Surfmaster I found in a review:
Gold- is loud and quick
Silver-haven't found it yet,sorry
Coins- are medium sound and quick
Pull tabs- are soft and the tone last longer
Iron-double tones quick as with bobby pins:-)
sounds similar to Excals responses....
(I dig it all anyway

Keep on diggin, if you hunt wet salt, pulse is the way to go !! HH to you, Herbie.