Here are some samples for the topic here: http://www.hydrogenaudio.org/forums/index....showtopic=99125 (http://www.hydrogenaudio.org/forums/index.php?showtopic=99125) . These ones are from System Shock 2. The first one is the ADPCM sample followed by the uncompressed one.
By comparision, here is the whole song (I don't think any copyright is being violated as the FLAC soundtrack was released freely on the internet by someone who appear to be one of the original developers here http://www.ttlg.com/forums/showthread.php?t=113469 (http://www.ttlg.com/forums/showthread.php?t=113469) ) in 44 Khz lossless, 22 Khz downsampled but without lossy compression, 44 Khz IMA ADPCM and 22 Khz IMA ADPCM. The soundtrack had to be broken up into small parts in the game (because of the Thief engine and to make quickly changing music according to location and situation possible).
44 Khz MS ADPCM version.
Here are the difference noise samples.