Tuesday night in Clarkston, three generations of Pinders — Harold the grandfather, Howard the father and 13-year-old grandson James — will perform in the DeKalb Symphony Orchestra. Harold, a retired Dunwoody engineer and double-bassist, has played in community orchestras most of his life. At 45, Howard is an electrical engineer for Cisco. He played with the DSO years ago and recently returned to his seat in the first violin section.