The best way to find music in the Cambridge libraries is to start with iDiscover. Type some keywords into the search box and press return on the keyboard or the spyglass symbol onscreen to get a list of items (scores, CDs, LPs, DVDs and more) from libraries all over Cambridge:
You can then select the type of material you want, or you can also click on 'Advanced search':
You can use the 'Material type' drop-down menu on the right of the screen to refine your keyword search.
Two Cambridge libraries have particularly strong music collections: the Pendlebury Library of Music, based in the University’s Music Faculty on West Road, and the Music Department of the University Library.
In the University Library Music Department, you might need to search for items in old-fashioned card drawers, as roughly two-thirds of its notated music isn't currently searchable online. The University Library Music Department also has a backlog of items that haven't been catalogued yet. If you need one of those, don't give up: library staff are there to help you (check the opening and staffed times for the Anderson Room here).
If you are looking for musical manuscripts you can also try using ArchiveSearch, which covers a lot of Cambridge manuscript collections, as well as the University Library Department of Manuscripts and University Archives.
It may also be worth checking to see if your college library has any music collections. Many have CDs and some also have scores, including full orchestral and choral sets.