It's not often you get a rabbi and an imam trading verses but Algeria's El Gusto ensemble is no ordinary orchestra. Forty besuited musicians perform on everything from guitar, oud and banjo to zither, accordion - and violin played upright on the lap to save space.

A dozen lead vocalists were bracketed by two grand pianos, one boasting internationally-acclaimed pianist Maurice el Médioni. There were members in their seventies and older, wielding walking sticks, comb-overs and wigs.

Alongside Muslim musicians were Jewish ones, just as there were in the 1940s and 1950s, back when chaabi - a mix of Arabic, European and Jewish music brewed in the casbah - was the music to swing to in Algiers. Then the all-male El Gusto (good mood) were part of a united musical community, their people's music a fixture of weddings and religious festivals, before the war of independence splintered the French colony and started a Jewish exodus.

Chaabi made a comeback earlier this decade; now a series of events - a film, a Damon Albarn-produced album, this tour - have brought El Gusto together for the first time in 45 years.

So after some sober chants from both religions, sung as they were in the old days, the orchestra played songs from their golden age with rousing authority enhanced by a percussion section on hand drums (who removed their jackets in one choreographed swoop). Lyrics of love, freedom and longing drew ululations. The music - bluesy, swirling, perfectly phrased - brought hope and promised change.

• The Ramadan Nights season runs until 16 October (www.barbican.org.uk/contemporary).