Have you tried listening to different models? I have friends/docs who had the cheaper Littman's (the light, cardio II (?), cardiology III, master cardiology). i preferred the Cardiology III. I hate the sprague and very cheap types (hurt my ears and I can't hear anything). The Littman has the very nice soft earpieces, and they seal the ear for me to get rid of background noise and are gentle on my ear. My ear actually bled from those sprague type stethoscopes in school!!! Ouch!!!
A new find of mine is the Ultrascopes. They are very cute, come in all kinds of colors and designs in the diaphragm. I have a pink one with a stick figure nurse in it. LOL. It's got the same acoustics (to me, anyway) as my plain black Littman. Everyone comments on the Ultrascope (cause it's cute and different). LOL...I even had our medical director wanting to borrow it, and the patients just thought this 70 year old MD looked great with a Hot Pink stethoscope around his neck!!! He said he wanted one (not a pink one, though...darn it) too.
If you ever get a chance to listen with a Ultrascope, I highly recommend it!!! (And no, I dont work for Ultrascope or Littman!

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Good Luck finding one that works for you and your ears! There was a nice thread here not too long ago, with some tricks on how to mark your stethoscope so you can know it's yours from quite far away. I know from experience that even engraved, labeled, and marked Littmans get stolen. In fact, the 3 stethoscopes I *did* have marked all were stolen by some agency nurses a couple years ago. I still have my unmarked ones now. That's why I don't let anyone borrow anymore (I made one exception for the MD who had an emergency with no scope...but I never left his side). My advice would be to get a hip/waist clip and keep your scope there unless it's in your ears. Don't borrow it!!!!