Have been playing for a long time and have been fronting a working band for the past four years. My frustration is in that when I use third position, unless I use chords or octaves, it pretty much sounds like 2nd position. I really noticed this today while working with Taj Mahals "Everybodys gotta change sometime" it's done in the key of G so when I switch back and forth between a C and LO F harp it sounds very similar, that is unless I do octaves. Maybe it's just the style as eth Taj Mahals version of "Checkin up on my baby" using a Bb for third position it sounds like cross but that's how he does it. 

Hi Brian - I use 3rd position quite often (more than any other player I know actually). Keep in mind that there are MANY ways for 3rd position to sound different than 2nd (especially away from holes 4-6), but mastering the blues scale and playing all notes in tune outside of this area of the harp is more complex than standard 2nd position playing. More than likely, the reason what you're playing sounds like 2nd position is that in the middle octave while playing 3rd position, there are tuning similarities on the lower octave in 2nd position, which can make some licks/patterns sound similar to 2nd position. Since the lower octave in 2nd position is most players "comfort zone" this is usually a big help for players. 

Thanks very much. I think for me it's also a matter of my ear training, in other word I've become very comfortable with the sound of second position andperhaps I'm still chasing that sound in my muscle memory. Listening to Little Walters "That's it" last night made me feel that I should retune my ear to what i'm trying to achieve. Thanks again.

Each position on the harmonica will have it's own particular advantages and disadvantages, and sounds/patterns that work well. Little Walter's "That's It" is a great tune, as well as some early George "Harmonica" Smith 3rd position solos from songs like "Telephone Blues" and "Blues Stay Away". Just keep in mind, the more you want to stray from the typical 2nd position style of playing 3rd position (focusing on the middle octave), the more difficult it can get, due to the different layout of the scale and some bending issues. 

Brian...you hit the nail on the head! If your inner ear is hearing the sound of second position, this will spill over into almost any position you play. Spend some time listening to original players using third position and get that sound into your head...

btw, making third position sound like second is pretty sophisticated playing...most players usually make each position sound like that position and don't have the ability that you have right now...