How can I change the default bitrate for Audio File conversion in Windows 8.1 File Explorer drag and drop?

So, I replaced my old Windows Phone 7.5 device with a shiny new Nokia Lumia 1520 (love it). One of the things that attracted me to WP8, besides the fact that I really like the OS, was support for the m4a audio file format since most of my music is in iTunes in m4a (ALAC) lossless format. My bad for not doing more in-depth research. Even though the Windows Phone site lists support for m4a on WP8, I found out the hard way that it does NOT support m4a (ALAC) files. No problem, I had ripped all of my CD's to WAV lossless format through Windows media player several years ago and the WP8 site also shows support for WAV files. Wrong! Turns out it doesn't support that WAV format either. However, I found that if I use Windows File Explorer in Windows 8.1 to drag and drop the WAV files to the music folder on the Windows Phone that it will offer to convert those files to a supported format. The problem is that the files are converted to WMA with a 160Kb bitrate. I can live with the files in WMA format but I would really prefer a higher bitrate. I can't find an option anywhere in Windows 8.1 to change the default bitrate for the drag and drop audio file conversion. I've done a ton of internet searches and have not found any solution. I can't help but think there must be a registry hack or some other way to change the default setting. Does anyone know a way to do this?