"EdgeSounds' RatHole (formerly GenieSys RatHole) is a free, unique, nondestructive universal media compression utility. Its function is based on a principle of self-training neural networks. RatHole was especially designed for archiving all kinds of sound files and is capable of compressing to the amazing rate of 40-80%." More information can be obtained from the EdgeSounds web site.
it supports many audio formats..and i tested it with http://www.soundzone.info/sf2/UK-Fatonic05.zip and its lossless..(but not file date)
i have attached a packed file for "portability" testing as it should unpack correctly.. size (6332706 byte) checksum for data (8B5C133C) so please confirm..
i tested compression with winzip 12 (1024kb) winrar (945kb) 7-zip (1030kb) paq8p1 (572kb log file attached)..
so if its pure lossless..its good so its detection for different audio formats is great..