it's easily fixed by decreasing the volume of the sound in the file itself.
I took
Thief2\RES\snd\SFX\PAGETURN.WAV
and decreased the volume by 15 dB in audacity
everything sounds perfect now
http://www.mediafire.com/?sharekey=a...d71d83c0cb2532
(original backup included)
note:
your snd is most likely not a folder, but a snd.crf file, extract it and rename old snd.crf to anything else and place the file in the folder, overwriting the old one.
if you want it to be a crf again, make the snd folder into a zip file (not rar) and rename it from .zip to .crf