When is a Bflat not a B flat?
My lack of formal education is showing again so I’m turning to others for help. A few days ago ago I made a comment about playing (in other genres and as a bassist) in my favorite keys, E flat and B flat. A friend said quite emphatically that in folk/blues B flat and C sharp are the same note but in the classical world they are not. My friend (who I’ll say now that I love dearly) is not classically trend and prefers the singer songwriter/ old time styles as a skilled guitarist and first-class luthier) is quite emphatic about this. One of the things I know is that he is sensitive to having his knowledge challenged so I won’t be asking him directly how he knows this.
Of course I immediately looked at my guitar (classical of course), my flutes (wooden and Bohm) and my wife’s piano (baby grand). What I didn’t see is a distinction of any kind between B flat and C sharp. My fiddle and bass don’t have frets so I suppose some "shading" of those notes are possible and some embouchure adjustments are possible on flutes could happen. Still I’m pretty sure that a lot of "classical" music is played on piano and the B flat isn’t re-tuned between pieces.
Before I dismiss his comments as non-sense maybe one of you can fill me in on why he might think the way he does. Is there a difference between B flat and C sharp and why?