You Tube recordings give the choral works in concert performance. They are good for hearing the context and the full harmonies.
MP3 files help singers to gradually learn their individual parts by listening to electronically-synthesized sound.
ChoraLine sells rehearsal CDs or downloads for individual voice parts. This means that they can also be used for practise in places without internet connection (eg car journeys).
If you discover any other rehearsal aids that would be of help to our singers, or mistakes in the above, please let Christine Wright know.