It’s the quaver that makes the Ethiopian singer Mahmoud Ahmed’s voice so arresting. He seizes on a note, brief or sustained, and makes its pitch tremble as if its urgency could barely be contained. It’s a show of controlled intensity, and in the course of a song, it happens again and again, making each phrase leap out anew: with sorrow, with anticipation, with a plea. That quaver is coupled with emphatic rhythm and grainy determination in a voice that Ethiopians in and out of the country have prized since the 1970s. Mr. Ahmed’s 1975 album, “Ere Mela Mela,”helped introduce Ethiopian pop to a wider world, and in the 1990s, reissues of his recordings as part of Buda Musique’s “Ethiopiques” series brought him further international attention.
Ethiopians were singing along in Amharic to Mr. Ahmed’s hits, and the whole room was dancing, when he performed on Saturday at Pioneer Works, headlining the first show in Issue Project Room’s summer concert series there. He led a band drawn from musicians he often works with in Washington, joined by the saxophonist Russ Gershon from Either/Orchestra, a Boston group that has backed Mr. Ahmed onstage and in recordings.
With three saxophones, keyboards, guitar, bass and drums, the band charged into funk that has distinctive Ethiopian features. It uses modal scales, often five-note ones with a half-step somewhere, and countermelodies from keyboard or guitar that snake up and down in those modes. (They translate, to Western ears, as minor chords and diminished harmonies, like the exotica of themes for spy movies set in the Middle East.)
The rhythms in many songs trade the 4/4 of American funk and rock for a particular rolling six-beat groove goaded by a sharp accent on the third beat, even as the rhythm guitar keeps scrubbing, and the saxophones punch out soul-band riffs. The songs use Western instruments and some Western ideas — a lot of James Brown, a little rock and reggae — and they have clear-cut verses and refrains, yet the melodies keep them unmistakably North African.
Mr. Ahmed is 73, but he shook the rust off his high notes before the first song was over. He was singing love songs, sometimes with his hand over his heart, sometimes waving or jabbing the air; now and then, he took up the shoulder-twitching dance that Ethiopians and their friends were doing on the floor.
He was a soul man, stoking the dancing and then easing into a ballad, declaiming and lamenting and then building again, with his voice seizing every line and pushing it toward incantation. Each quaver rooted the music in Ethiopian tradition while insisting on the universality of passion.