Pappenheim is a frequent collaborator with contemporary composer-performers Simon Fisher-Turner, Orlando Gough and Jocelyn Pook, and is also a member of their respective musical projects.

As part of the Ensemble, she has contributed to the soundtracks of Hollywood blockbuster films, Eyes Wide Shut and Gangs of New York.

In 2009, at the invitation of producer Giles Perring, Pappenheim recorded for the album 'Poets and Lighthouses' by Tuvan singer Albert Kuvezin.

She has regularly performed Paul Clark's score 'Here All Night' - a words and music collaboration with Beckett specialists Gare St Lazare - in the UK, Ireland and US.

Her vocals on the track "Doomsday" (used in the dénouement of the eponymous episode) caused an influx of emails to the BBC about her contribution to the soundtrack.