today i while transcoding some stuff with mediacoder, i found a codec with an strange/interesting name (for those who are into media coding - as how can an uncompressed or loslessly compressed thing be lossy, its like 'lossy loseless", no sense), called lossy wav. i had no idea what it is so done some search. i 've read the stuff; and then decided to make a try - i transcoded a flac to wav and then that wav to lossywav using lowest possible quality, “portable”. then used zip compression with 7-zip using “fastest”; lossy became 89MB and the source (normal wav) became 117 - both was 133 uncompressed. (totally expectable result giving the nature of the thing, see the HA link above) (the flac was 63 and i didnt code the lossy with flac as this is not our purpose (et can take only wav) but likely it would be less than 63.)
soundpacks, and maps containing sounds, can save a few, lets say 5-10%, if the resulting file is recognized by ET; this will have to be tested, i didnt bother iwth it as in near future i will be nowhere in demand of using sounds, lots of brushwork&texture making to do i have. (sources say its a totally regular wav file so i have high hopes)
off topic - i also tested this earlier, and i dont think many ppl aware - et recognises RLE encoded tga! this is not much more efficient than uncompressed tga in zip but somewhat it is (maybe 1-2%?). (ofc u should use jpg whenever u can but its not always possible). in ifranview, (otherwise a very cool thing) u cant choose this as saving option but in gimp u can.