Unravelling the secrets of choral singers
Scientists believe there might be more to choir boys' and girls' voices than meets the ear.
Professor David Howard from the University of York has been monitoring the unique sets of frequencies in young choristers' voices.
He believes that soloists' voices have particular energy at around 8000Hz, which gives them a special shimmering, resonating sound.
He shows science reporter Rebecca Morelle how he carries out his acoustic experiments in his anechoic chamber.