These are the audio files for Nessun Dorma. Download the file for your part, plus the file that is just called Nessun Dorma Choral, which has all parts.
The MP3s are missing the first bar you have in your score. In terms of instruments used, sopranos are violin, altos church organ, tenor trombone and basses bassoon; the introductory solo part is played as a piano in the Nessun Dorma Choral file. The sound is also panned in the stereo field, so sopranos and tenors are fully on the left side; altos and basses fully on the right side. There is a click track in the individual part files, to count out the first four bars.