What version are you running? https://sourceforge.net/projects/sox/files/sox/14.4.2/sox-14.4.2-win32.zip
okay so from reading another thread:
Do I have to install the DSD patches? I'm running windows and trying to figure out what files from the following site to download and where to install/place them:
A while back Mans Rullgard added support to SoX for DSD resampling. It applies the SoX resampling to 1bit DSD directly. https://github.com/mansr/sox
A cursory glance at that computeraudiophile thread shows that someone found this link from which the file sox-dsd-win32-MSVC.zip can be downloaded. I downloaded a DSD64 (which I believe is the kind of encoding SACD's use; correct me if I am mistaken) file from here and managed to convert it to FLAC with the included SoX.exe executable included in the ZIP file (extract all of the compressed file first).
I used the following batch file in Windows 10 with the executable in question:
for %%a in ("YourInputFolderHere\*.dsf") do sox -V3 -S -D "%%a" -b 16 "YourOutputFolderHere\%%~na.flac" rate -v 44100
I had to include the "-D" parameter to stop SoX from dithering; I'm not sure why it was automatically doing this. Maybe it's better? I'm not too sure.
Anyway, this is if you want to encode it in standard CDDA quality (16-bit stereo, 44.1kHz). You can change the bit depth and sampling frequency to whatever you want the FLAC output to be.