A dulcimer usually has two
bridges, a bass bridge near the right and a treble bridge on the left side. The bass bridge holds up bass strings, which are played to the left of the bridge. The treble strings can be played on either side of the treble bridge. In the usual construction, playing them on the left side gives a note a fifth higher than playing them on the right of the bridge. The dulcimer comes in various sizes, identified by the number of strings that cross each of the bridges. A 15/14, for example, has 15 strings crossing the treble bridge and 14 crossing the bass bridge, and can span three
octaves. The strings of a hammered dulcimer are usually found in pairs, two strings for each note (though some instruments have three or four strings per note). Each set of strings is tuned in
unison and is called a
course. As with a
piano, the purpose of using multiple strings per course is to make the instrument louder, although as the courses are rarely in perfect unison, a
chorus effect usually results like a
mandolin. The strings of the hammered dulcimer are wound around tuning pins with square heads (ordinarily, 5 mm "zither pins" are used, similar to, but smaller in diameter than piano tuning pins, which come in various sizes ranging upwards from "1/0" or 7 mm), and tuning requires a
wrench as for an
autoharp, harp, or piano. The strings of the hammered dulcimer are often tuned according to a
circle of fifths pattern. Typically, the lowest note (often a G or D) is struck at the lower right-hand of the instrument, just to the left of the right-hand (bass) bridge. As a player strikes the courses above in sequence, they ascend following a repeating sequence of two whole steps and a half step. With this tuning, a
diatonic scale is broken into two
tetrachords, or groups of four notes. For example, on an instrument with D as the lowest note, the D
major scale is played starting in the lower-right corner and ascending the bass bridge: D – E – F – G. This is the lower tetrachord of the D major scale. At this point the player returns to the bottom of the instrument and shifts to the treble strings to the right of the treble bridge to play the higher tetrachord: A – B – C – D. The player can continue up the scale on the right side of the treble bridge with E – F – G – A – B, but the next note will be C, not C, so he or she must switch to the left side of the treble bridge (and closer to the player) to continue the D major scale. See the drawing on the left above, in which "DO" would correspond to D (see
Movable do solfège). The shift from the bass bridge to the treble bridge is required because the bass bridge's fourth string G is the start of the lower tetrachord of the G scale. The player could go on up a couple notes (G – A – B), but the next note will be a flatted seventh (C natural in this case), because this note is drawn from the G tetrachord. This D major scale with a flatted seventh is the
mixolydian mode in D. The same thing happens as the player goes up the treble bridge – after getting to
La (B in this case), one has to go to the left of the treble bridge. Moving from the left side of the bass bridge to the right side of the treble bridge is analogous to moving from the right side of the treble bridge to the left side of the treble bridge. The whole pattern can be shifted up by three courses, so that instead of a D-major scale one would have a G-major scale, and so on. This transposes one
equally tempered scale to another. Shifting down three courses transposes the D-major scale to A-major, but of course the first Do-Re-Mi would be shifted off the instrument. This tuning results in most, but not all, notes of the
chromatic scale being available. To fill in the gaps, many modern dulcimer builders include extra short bridges at the top and bottom of the soundboard, where extra strings are tuned to some or all of the missing pitches. Such instruments are often called "chromatic dulcimers" as opposed to the more traditional "diatonic dulcimers". The tetrachord markers found on the bridges of most hammered dulcimers in the
English-speaking world were introduced by the American player and maker
Sam Rizzetta in the 1960s. In the
Alps there are also chromatic dulcimers with crossed strings, which are in a whole tone distance in every row. This chromatic
Salzburger hackbrett was developed in the mid 1930s from the diatonic hammered dulcimer by Tobi Reizer and his son along with Franz Peyer and Heinrich Bandzauner. In the postwar period it was one of the instruments taught in state-sponsored music schools. Hammered dulcimers of non-European descent may have other tuning patterns, and builders of European-style dulcimers sometimes experiment with alternate tuning patterns. == Hammers ==