I recently bought the compadre with the 8" coil. I have read a great deal about this machine, and I realize it is only a one tone machine, but that the tonal quality will change which will give an idea of depth, or help with target discrimination. I have been using a set of headphones that I bought at a garage sale a couple of years ago, and I have noticed some tonal differences like pennies and pull tabs come across loud and clear to the point where they practically blow my ear off. Today I noticed this whisper of tones very faint, and very light. It was almost like an echo. I could barely hear it, so I turned up the volume on the phones, and I could still barely hear it. I am wondering if my headphones are just not equipped to pick up this tone? Have others with this machine heard very quiet tones? I have only had this machine for a couple of weeks, and have no complaints, but have noticed that I have dug a large quantity of pennies and pull tabs, due to the fact that they come across so loud, and I realize this comes with the territory, but now I am wondering if I have missed a bunch of targets because I have not been hearing these very faint tones. Any input would be greatly appreciated. If it is the phones, what should I be looking at purchasing?