I've been curious about that. If most of your music is 44.1kHz should you set windows to that? Or as I've read elsewhere, supposedly its better to resample to 48kHz?
It's a better choice IMO not to resample at all, but to send the original sample rate of the file--WHATEVER it is-- directly to your device, by-passing the Windows Mixer altogether. You accomplish this by using the WASAPI-Exclusive output, as discussed above. The only limitation to this is if the original file has a sample rate that is not supported by your actual audio device. In that case, IN MY EXPERIENCE (such as it is), the bass.dll will resample the rate on its own to 44.1khz--alternatively, you CAN use the MusicBee internal resampler to set whatever rate you want, as long as you know that as long as you use it EVERYTHING will be resampled to the chosen rate.
From what I've read, the collective wisdom is that the use of any modern resampler (Sox, etc.) will not add any audible changes to your music. But I prefer to keep the path as short as possible, which is why WASAPI-Excusive. As also mentioned before, ASIO will do that too, but seems more "twitchy" to set up properly based on what I've seen posted in the Forum.