Garf, could you please make this sample available again?
I still have that file and just ran it through a bunch of lossless audio compressors (plus the old and new WavPacks, of course):
Original File
-------------
10,584,044 garf.wav (orginal file)
Monkey's Audio 3.97
-------------------
5,642,404 garf-xh.ape (extra high mode)
5,494,040 garf-h.ape (high mode)
4,530,440 garf-n.ape (normal mode)
4,527,024 garf-f.ape (fast mode)
FLAC
----
4,425,222 garf-1.flac (mode 1)
4,397,071 garf-5.flac (mode 5)
4,392,479 garf-8.flac (mode 8)
OptimFROG 4.507
---------------
53,186 garf.ofr (default mode)
2,985 garf2.ofr ("newbest" mode)
RKAU 1.07
---------
164,261 garf-1.rka (fast mode)
590,353 garf-3.rka (high mode)
LA 0.4
------
3,343,564 garf-h.la (high mode)
2,364,142 garf.la (default mode)
WavPack
-------
2,134,878 garf-ff.wv (3.97, very fast mode)
1,476,068 garf-ff.wv (4.0a2, very fast mode)
766,124 garf-ffx4.wv (4.0a2, very fast mode, extra processing)
1,804,879 garf-f.wv (3.97, fast mode)
1,503,778 garf-f.wv (4.0a2, fast mode)
769,248 garf-fx4.wv (4.0a2, fast mode, extra processing)
4,034,834 garf-n.wv (3.97, default mode)
1,741,260 garf-n.wv (4.0a2, default mode)
770,792 garf-x4.wv (4.0a2, default mode, extra processing)
4,035,317 garf-h.wv (3.97, high mode)
2,675,828 garf-h.wv (4.0a2, high mode)
768,158 garf-hx3.wv (4.0a2, high mode, extra processing)
The first interesting point is that WavPack, RKAU, LA and Monkey's Audio all have the characteristic that the "higher" modes do worse than the "faster" modes.
Second, the "extra" processing mode does significantly help WavPack's performance with this sample.
Finally, OptimFROG is pretty amazing. Good job, Florin!