Performance is merely the first step in the way we hear music. Acoustics of concert halls, churches, electronics and recording, or broadcasting all modify the original sounds, often quite dramatically. Even in the best auditoria no two seats will receive identical sounds. Buildings designed for different types of music will rarely perform well across a range of musical performances. Understanding this can help in the choice of seating. For music that is broadcast or played from recordings there are considerable changes from the electronics, recording, transmission, reception, home electronics, and acoustics. This chapter examines many possible situations and the attempts at optimization. Hearing differs considerably between people, and it changes with age and our level of concentration.