String size
General mountain dulcimer or music discussions
Marg, when I think about "tone quality", I think of three things pitch, volume and timber. String choice has an effect on all of these. First, let's define what I mean:
Pitch: the note to which the string is tuned. You also see this referred to as tension. More tension = higher pitch, less tension = lower pitch. Lighter weight strings can be tuned to a higer pitch than heavier strings because they require less tension to reach that pitch.
Volume: loudness. Heavier strings can produce greater volume than lighter ones
Timber: (pronounced tam-ber) This is all of those sound qualities that are not Pitch or Volume. Highly subjective and influenced by many many factors such as Wout mentions above: body design, wood choice, string materials, etc.
So, string choice is really a personal choice as to what you think sounds best on your instrument. For example, for many years I have played medium weight, John Pearse phosphor bronze wound strings on my guitar because I get greater bass response and a warm tone. Right now I like the McSpadden flat wound (squeakless) strings on one of my instruments because thery sound mellow and sweet on it and I have another strung up with nickel wound tenor banjo strings because they are brassy and bright. (and I found them at my local music shop in a pinch)
Robin Thompson plays an instrument with all plain steel strings of the same guage tuned to the same note.
Have fun and don't be afraid to try something new!

The West Virginia fiddler Ernie Carpenter wrote the song (in the 1950s, I think) and you would expect it to be under copyright. However, I have not found any evidence that the song is copyrighted, and everyone (not just dulcimer players) seems to both credit Carpenter for its composition and also post music and tablature freely.