Casper Allen is a traveling country and folk singer-songwriter who has pulled off the eternally eerie gift of possessing an old man’s voice and bearing in a young man’s body. Originally from Texas, he is a touring road dog of the first degree and worth an evening of your time, which you can enjoy at Synapsis at 8 p.m. ($20). Clyde McGee from Bridge City Sinners is a good choice as an opener.