Interview 1: subject-related discussion; Interview 2: text-based and subject-related discussion
Analyse landmark pieces of music; read musical dictionaries
Nothing to add!
Remember this advice isn't official. There is no guarantee it will reflect your experience because university applications can change between years. Check the official Cambridge and Oxford websites for more accurate information on this year's application format and the required tests.
Also, someone else's experience may not reflect your own. Most interviews are more like conversations than tests and like, any conversation, they are quite interactive.
Test taken: None
Number of interviews: 2
Skype interview: no
Time between interviews: 4 hours
Length of first interview: 25 minutes; Length of second interview: 25 minutes
Various scores that had been given to me 15 mins before the interview. The first was a kind of theory aptitude test and involved some discussion of 20th century music. There was also discussion about why some music is better 'accepted' than others.
The second interview was a discussion of a text about the history of music. This interview also involved more philosophical discussion as well as the opportunity for me to ask the fellows general questions about music and life at Cambridge. The atmosphere in the room was welcoming, the interviewers where clearly excited to meet me. However I was inevitably
Do some brief analysis of landmark pieces in each major era of music, maybe looking at harmony and structure, taking 7-10 mins for each piece.
Also, read lots of musical dictionaries.