Note; if you are playing these on iphone or ipad, you may find it easier to download a different app to play it on because itunes isn't the easiest.
I use Denon Professional Pitch Control which is free and can also play mp3 files slower or faster whilst still maintaining the pitch.
You can download all or part of your library into it
You can also cue sections which makes it easy to repeat the dodgy bits over again!
Andrew's Brahms Requiem mp3 rehearsal files
Alternative mp3 files converted from midi
Synthesised for note and timing bashing:-
These files have been optimized for the Novello English version. The singers part will be on the right stereo channel with the greatest volume, the rest of the voices in that choir with lesser volume on the left stereo channel, and the continuo balanced across both stereo channels at a lower volume.
Thus if you set your stereo balance to the centre you will hear a reasonable balance of all parts and still be able to distinguish your part. However if you set the balance to the right, you should hear your part dominating strongly. Conversely, if you set the balance to the left, your part should be almost inaudible
To hear the mp3 file, just click on your partin the row next to the section you want to hear. If you can, save the files onto your conputer or mobile device so that you can play them wherever you are.