I am haveing trouble hearing the hi low tones on the conductiverty of different metals,I have turned Bi level on but it is very hard to pick the the tones between feros and non feros.On my ace it is very distinctive and bell tone is better, The GTI lights up very well on our $1 and $2 coin but the silver coins are a bit differrent,our pre decimal coins realy ring in as well which is what I mainly look for, I am still learning on this detector and realise I have a long way to go. 
