Metal detector question Help?

[just lookin]

I posted in the mod, section, but I might not have explain what I was asking!So I will ask a little better. The way I understand, there are alot of different types of design's, what I would like someone to explain to me is this, on some detectors, they have high, low and in between tones as they detect different types of metal's. I have just came up with a brown box Eldorado, I have tested it with coins, pulltabs, ect. and I cannot notice much audio difference in the different targets, the detector just came back from the factory, so it must be working okay??Is it possible to mod this detector so that it changes audio pitch on different targets. I know this is a dumb question, but hopefully someone can and will explain this to me.
Thanks Greg :confused:

[diggerbarns]

Eldorado only does one tone. you hear the same tone for any positive target. Never seen a tone ID that was any use anyway. Just another bit of detecting clap trap.