Windows 8.1 / Foobar with WASAPI plugin. I can select 32bit in foobar but it gives me an "Unsupported stream format:" error. Also the device settings in Windows control panel only list up to 24bit 192khz.
Using a bunch of test files i can play everything up to 24bit 384khz via WASAPI, including 176k and 352k which i had never heard of before. Its just 32bit streams i cant do.
P.S. Installed JRiver and have the same issue, set the output to 32bit floating or integer and it gives an error on playback.