How do I know what key I'm in?

Dusty Turtle
Dusty Turtle
last year
1,489 posts

Nate, as Ken and Skip have explained, the notion of key on a modal instrument gets a little tricky.

I would just define a key as the tonal center of a piece of music, the tone that seems to represent rest or resolution with the other notes creating different degrees of tension.  

Your effort to determine key by examining the sharps and flats of a piece makes sense in western classical music, and you are correct that the key of D major has a C# and they key of G has a C natural.  That "key signature" defines the major scale, or the Ionian mode.  However, with traditional, modal music, any mode can be played in any key, so the key, or tonal center, does not necessarily determine the scale pattern. To use the most common examples, D Ionian uses the C sharp, but D Mixolydian uses the C natural. 

In fact, those examples explain why the 6+ fret was added.  On a true diatonic dulcimer tuned to D, tuning DAd would not give you a major scale (Ionian mode) precisely because the 6 fret is a C natural.  To play the major scale, one would tune DAA and start the scale at the 3rd fret.  Then you get the C# on the 9th fret.  To avoid having to retune, dulcimer players about a half century ago began adding the 6+ fret so that they could play in the two most common major-sounding modes, the Ionian and Mixolydian, without re-tuning.

Let's also remember that a lot of folk and pop music doesn't use all the notes of the scale or mode.  A lot of music is pentatonic, meaning only 5 notes are used.  And heck, the old song by the Chrystals, "Da Doo Ron Ron," only has three notes in it!

"So what?" you might ask.  Good question.  My point is that every song has a key, meaning the tonal center or "home base" even if it does not make use of the scale indicated by the key signature.

Having said all this, I would guess that 90 percent of the time when you are tuned DAA or DAd you are playing in the key of D (or Bm, the "relative minor").  If you fret across all the strings, then you can also play in G and perhaps (though it gets tricky) A.  I've recently been arranging several tunes that work in both D and G on the DAd dulcimer. That way you can modulate after a couple of verses and impress your friends and family.


Dusty T., Northern California
Site Moderator

As a musician, you have to keep one foot back in the past and one foot forward into the future.
-- Dizzy Gillespie

updated by @dusty-turtle: 10/05/20 01:30:02AM
last year
291 posts

I learned several years ago that it is much easier to understand music theory, as applied to MD, when the word 'key' [in music] has several definitions. One defines or indicates the specific notes in a scale [the one you found], another, more generic, refers to the lowest note in a scale, regardless of the notes involved. The second one can also be a 'keynote' or 'scale center'.

So, in your tune, the written 'key' scale [def 1] is G; the 'key' on the instrument [def 2] is D. 

The 6+ can be considered an additional fretboard overlay that modifies the mode layout of the frets. Two fret board layouts, 1 without the 6+, one without the 6. 

updated by @skip: 10/04/20 07:27:10PM
Ken Hulme
Ken Hulme
last year
1,870 posts

Normally, "the key I'm in" is the open note of the Bass string.  That is, the entire instrument is tuned to a particular keynote -- C, D, G, whatever.  

The + frets are not there to supply notes -- not just sharps or flats -- above and beyond the diatonic scale.  The 6+ fret in particular was added to the fretboard because people wanted to be able to play a C natural as well as the C# which is 'natural' to that diatonic scale. 

When I first learned all this we talked about Modes, and the idea that players wanted to be able to play in more than one Mode with re-tuning.  DAA (a.k.a. Ionian Mode) is what guitar folks think of as the Natural Major Scale.  DAd (a.k.a. Mixolydian Mode) is almost the same -- except that the 7th note of the scale is "flatted" (a half step below what it would be in the Natural Major scale).  The 6+ fret was added so that players could play both the natural and the flatted 7th note of a scale starting on the Open fret.

Years ago I wrote the attached article about modes (scales) and the diatonic nature of the dulcimer.  It might help you understand things...

last year
76 posts

Hey guys I have been trying to practice writing my own tab and I wrote out tab by ear for an old folk song called sally wheatley. Because I did it by ear, and I'm still just beginning to learn music theory, I didnt really know what key I was in. because I didnt use any half frets my first thought was that I was in the key of D, but I noticed the key of D has a C sharp, and my arrangement has a C natural, so I think this means it is in the key of G? This seems weird to me because I assumed that since the dulcimer is diatonic, that the non half frets would be the diatonic scale, but if C# is in the scale of D, why is it the 6 1/2 fret? whereas C natural is the 6 fret. Would love some help this stuff is not very intuitive to me !