Strings play a much smaller role on Visitors (Tone Rogue), the debut album from co-leaders Christian Li (piano, keyboards) and Mike Bono (guitar). But when violinist Alex Hargreaves and string player Chris Marion insert their bowed sonic input, ears perk up. Hargreaves enlivens Li’s restless, antic “Little Rascals” and Bono’s tartly moody “Tango,” while Marion’s layered string sound waxes darkly ethereal on the finale, “Heart.” Also featured are cameos from the stellar tenor saxophonist Dayna Stephens.