促弦

cùxián

подтягивать струны

cùxián

[wring string of a musical instrument to be ever so straight] 把弦拧紧

感我此言良久立, 却坐促弦弦转急。 --白居易《琵琶行(并序)》

cù xián

to tighten the strings (of a musical instrument)