Having played the hammered dulcimer for about 16 years I can say that
Dulcimer Dan is the man:  http://www.dulcimerdan.com/  This YouTube clip 
is classic Dan!  This reminds me I still need a _lot_ of practice!!

Being raised in East Tennessee this music reminds me of the Appalachian
festivals, especially at Jonesboro.  This is where I first became
interested in playing the hammered dulcimer.

The hammered dulcimer is not a chromatic instrument.  Many times the
accidentals need to have other note strings tuned to the pitch or most
of the times Dulcimer players fakes it by embellishing by it or by
combining different notes that fool the ear.  It is amazing how the
brain can "fill in the blanks."

Well, I could go on about the construction, bridge layout and tuning,
and my experience restoring my dulcimer, but I don't believe many folks
here would be that interested.

Sam Harris
Greenville, North Carolina