# Can I play `A scale` song on a `C scale` harmonica?

Here is how to play a `C scale` on a harmonica. But I found a song which is in the `A scale`. So, is this possible: to play the `A scale` song on the same harmonica? If so, What would the table look like? or how can I change the `C scale` to `A scale`? Is there any algorithm to do so? For example, when I change it to `E scale`, is there any equation to do so? Thanks.

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Do you mean A Major, I suppose? – American Luke Nov 28 '12 at 14:39
@Luke, you raise a good point. You wanna write an answer about relative minor? I was about to add more, but I think I've milked it enough. :) – luser droog Nov 30 '12 at 10:32

You can play the A scale on a C harmonica. But you'll have to bend overblow all the C's (♯1 (or use ♭2, if ♯1 is not available)) F's (♯4 (or substitute ♭5)) and G's (♯5 (or ♭6)) because the A Major scale goes: A B C♯ D E F♯ G♯ A.

For Blues, don't raise the G. Use the A mixolydian scale instead: A B C♯ D E F♯ G A.

Or, for harder Blues, use the A minor pentatonic: A C D E G A.

For really hard Blues, play the blue notes. But you have to find them in the middle of the bend because they exist partway between the notes of the diatonic scales. In A, there's one between C and C♯ and between E and F♯ and between F♯ and G.

To learn the "algorithm" for finding the sharps and flats in a scale, read about The Circle of Fifths/Fourths, Key Signatures, Key Modulation, and maybe even The Pythagorean Comma.

Using the Circle of Fifths, you'll see that E is one step farther from C (no sharps/flats) than A (3 sharps). So it has 4 sharps. The same three from the A scale plus the new leading tone (Major Seventh) D♯ instead of D.

I've heard it's common for a player to have several harmonicas in different keys. Usually they're not too-many steps (fourths or fifths) away from C. So a small set would be C, F (or B♭), and G (or D). It's also common for a player to choose the harmonica that's keyed to the fifth to make the mixolydian (♭7) <-> ionian (Major 7) transition simpler. So for a song in A, you'd grab the D harmonica. This can help put the melody in the sweet spot. [This paragraph assembled from heresay, use at own risk.]

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your last para. is o.k., as in ,playing with a blues band, songs in E for example, you'd use an A harp, as sucking this will produce a sort of E9 chord, allbeit without the root. – Tim Dec 2 '12 at 16:51
Is this overblowing suggestion just theoretical or do real players do this to change keys? I'm not asking about the blues scale stuff. That part is understood. – Michael Curtis Feb 4 at 17:48
@MichaelCurtis I've seen it done in youtube videos. But I've never been able to do it myself. I'd probably bend down to get those notes, to be honest. – luser droog Feb 6 at 17:20
@LuserDroog, can you share a video link? The only example I can find is this: youtu.be/_mgBmwxhJuA?t=6m45s. In the video he only deals with one altered note as apposed to three altered notes to get A major from C major. It also doesn't seem like a practical technique for changing key. – Michael Curtis Feb 8 at 19:13

You're probably better off getting a harp in the appropriate key - much less bother - or - get a chromatic harmonica (with a button at the side ) to give all the # and b neccessary, so you can play in any key you like. They're often based in C maj. anyway, so can still work like your existing one.

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