I had the experience today of holding a "fake" 1924 peace dollar andan original! The store keeper told me that one was real and one was fake.....and ask could I tell for certain which was which? I examined both and he even dropped both to check the sounds. After inspecting both I said I could identify with 100%certainty the "real deal". He said prove it! I simply went and got the f5, set the gain low, thresh @ 0 , and maxed the disc. , 3 tones! He placed each under a short stack of magazines...one gave a high pitch but showed only a low 70's number. The other showed a 88and a 92 on vid and darn near popped my ear drums! I let him see and hear the difference and we both said this was the best to quickly find out if a coin was real! I learned something today.........buyer beware,beware,beware!