The tro is Cambodia's traditional spike fiddles, bowedstring instruments that are held and played vertically. Spike fiddles have a handle that passes through the resonator, often forming a spike, on the bottom side where it emerges. The family is similar or distantly related to the Chinese erhu or huqin. The instruments have a soundbox at the bottom of the stick, covered with leather or snake skin. Strings run from pegs at the top of the stick and secured at the bottom, running across the soundbox. The larger the soundbox, the lower the pitch range. Instruments in this family include the two-stringed tro ou, tro sau thom, tro sau toch and tro che, as well as the three-stringed tro Khmer spike fiddle. The two-stringed tros are tuned in a fifth, while the three-stringed tro Khmer is tuned in fourths. The tros, with the exception of the tro Khmer, are strung so that the bowstring is permanently placed between the two stings. When the musician plays, the placement of the bow causes the strings to be played at once, one from below and one from above. In contrast, western fiddles are played with the bow pushing on each string from the outside, as is also the case with the tro khmer.
Tro family of fiddles
The tro u is a traditional instrument from Cambodia that dates back at least as far as the "Lungvek period," about 1528-1594, and is the lowest pitched tro, with strings tuned in a 5th, approximately C—G. The resonator bowl is constructed from a round-bodied coconut shell that has one end covered with animal skin, such as snake or calfskin. Its two strings are made of silk, gut, nylon, or metal, running over a bridge made of bamboo or wood. The coconut may have designs carved into its back-side. It is similar to the Thai saw u and the Chinese yehu, although the latter instrument has a wooden rather than animal skin face. Played in the mohori and ayai ensembles. May be used in the Bassac theater orchestra. The tro ou chamhieng is played "exclusively" by Cham who live in Cambodia and has a sound-bowl resonator made from a turtle shell. It is played in the Bassac theater orchestra and the yike orchestra. The tro sau or tro sau thom is a bowed stringed instrument from Cambodia, with metal strings tuned in a 5th, approximately D—A. The thom is the larger and lower-pitched tro sau; thom means "big" in Khmer. The cylindricalsound box is approximately 120 mm long and 90mm across the skin head. The neck can measure 620mm long. It is made from black wood but more basic materials were used, such as a hollow bamboo and a tortoise shell. It is used in Cambodian classical music ensembles, the arak, kar, mohori and ayai. It is not the lead instrument in these ensembles. The tro sau toch is a Cambodian instrument used in Khmer classical music. It is a two-string vertical fiddle with a hardwood body. The word toch means "small." The sound box can measure 80mm wide by 115mm long, the neck 760mm. Measurements are approximate as the instruments are not standardized. It is equivalent to the Thai Saw duang. Its two metal strings are tuned in 5ths, G—D, higher than the larger tro sau thom. It is used in Cambodian classical music ensembles, the arak, kar, mohori and ayai, as the lead instrument. The tro che or tro chhe is a member of the tro family of 2-stringed Cambodian fiddles, the smallest member of the tro family. Its two metal strings are tuned D—A, an octave above the tro sau thom and the highest of the tros. Instrument tunings are approximate in the Cambodian ensembles, and change with key instruments such as the sralay; when the instrument is played in the bassack theatre orchestra (paired with the tro ou instead of tri sau thom, the tro che be tuned the same as the Tro u, one octave higher. Like most of the other members of the family, it is a two stringed instrument. Formerly, silk strings were standard, but now metal wire or cable is used. The resonating chamber, a cylinder, is made of hardwood or ivory. There are no standard sizes; however the resonating chamber can be 65–70 mm across and 105 mm long. The skin soundboard, is made of snakeskin or pangolin hide.
