Regarding playing the 3rd a bit flat, I find myself doing the same thing against a major chord and I think it adds interest. For me, it doesn't work as well for melodies unless you skip across it and it doesn't work at all for European folk stuff.
Regarding harp tuning, I have S20 and GM harps. I find all my harps play a few cents sharp according to the tuner. When I pluck the reeds that effect goes away. I conclude that I have a tendency to play a bit sharp, and I have no idea why that is so. The result is that I don't concern myself with the various harp tunings. I just concentrate on how I am playing.
I'm playing Bushmans and Suzukis which are equal tuned. Should be dead on for playing single notes.... well actually harps are almost never tuned dead on. But close.
What harp are you playing? Just Intonation (Herring, old MB), Equal temperment (Golden Melody), or something in between (Sp 20, LO) may have slightly different pitches on the 3 draw. I don't have a tuning chart in front of me, and I think the 5 draw is the BIG difference (like 12 cents) between these tunings, but it could make a difference. Have you checked your 3 draw unbent with a tuner?
All that said, it might just be that a hint of a bend (1/8 - 1/4 step?) gives it the right bluesiness or sound for that song. Can't say I've intentionally done that or even noticed it, but it sounds plausible. But could also be that the compromises made with standard tunied harmonicas puts that note a little off of where you want to be...
Hey all, wanted to run a few thoughts past you all on the flat 3rd note (3 draw single step bend in cross harp) and see what you thought.
Learning to play blues most of us are taught to always bend the 3 draw to get the flat 3rd to sound bluesy. I agree. When you play it unbent in a blues it sounds OK but definitely not bluesy. Its the old major/minor thing going on with blues. I get this.
I'm not into country all that much but I do play some country/rock kind of songs. We play Doolin Dalton by the Eagles and to my ear the 3 draw sounds best when slightly bent - not all the way to the flat 3rd, just a little flat. And not just as a passing tone, I hang on it a little and it still sounds best that way. I would think that in general you would want to play the note unbent, or bend it to pitch - playing it slightly flat would seem to be a bad idea. But I've been playing this a long time and it definitely sounds best that way when we play it. Anyone else ever bend the 3 a little flat but not all the way to the flat 3rd? Is this common?
Now what really brings this question up is the following. Someone has asked me to play harp on a country song for them. Its an original, but think "real" country ... George Jones playing "He stopped loving her today". As I'm fooling around with the song looking for something that sounds good on harp, again I find myself liking the sound of that 3 draw pulled slightly flat. The band is playing straight major chords and the unbent 3 draw sounds fine, but pulling it slightly flat seems to give it some character. Again, does anyone else do this? Is my ear out of tune .... hahahah.