I was out today with my EX2 and was hunting a really junky area. Put on my 8 in coil and started finding coins. One thing I noticed that on the really junky clad quarters, the ones that have been in the ground for quite a while and are almost unreadable would give off the high chirp and would read 00-28-00-30 but no flute sound Just a high pitched chirp.The newer ones would give the normal warble. If I was going by the sound alone I probably would have passed them by