Was interested in trying this - seeing others used "indirectsound" I googled and found another supposed convertor - the open source Open AL Soft mentioned.
Not sure if this really worked for me or not - installed and setup EAX following Storebrors original post and mediafire link on current system including changes to IL2 config etc -booted IL2 BAT and seemed to get the correct logs and quieter sounds and some reverb but not really impressive.
I then dowloaded "OpenAL Soft" from
https://openal-soft.org and extracted the zip.
First tested setup (prior to renaming the included dll) via the included openal-info64.exe and this showed limited EAX extensions/support - next renamed the included OpenAL Soft.dll to OpenAL32.dll (note on my 64bit win 10 system this file is in the windows/system32 folder) then re ran the openal-info64.exe and that showed numerous additional extensions.
Reloaded IL2 BAT and sounds seemed much improved than the original EAX - so either it doesn't work and sounds are as before installing EAX or it actually works definetly sounded better than the original ALchemy version.