There is a particular kind of arrival that marks not just a journey but a threshold — a young artist stepping into a room that has never heard him play. Malcolm Todd, a 23-year-old American singer-songwriter whose songs have traveled far ahead of him, will make his Singapore debut on November 30 at The Star Theatre, part of an eight-city Asian sweep tied to his second album, Do That Again. The tour is both a commercial undertaking and a test of whether the intimacy of recorded music can survive — and deepen — in a live room full of strangers becoming believers.