Actually that was my fault, the libspeex package i uploaded was for dynamic linking, not static linking.
You need to remove the libspeex.dll.a from the "lib" dir where you just unpacked it to (just the ones with dll in them, not libspeex.a), otherwise you'll also need to put the libspeex-1.dll into the LAV folder.
I posted corrected library zips, just when you already unpacked it, it won't remove the old files
