Mikkel Breiler wrote:

retaining the full quality you could rerip the cd into mono,

Good idea. The ripper I'm using doesn't have a mono option, but I'm
sure others do it.

If you rip into a WAV file then you can use any encoder that offers a
mono option.

Yup, I use Goldwave for exactly that purpose. Open a stereo file, tick mono
box, save - job done!