Can you add 6channel audio files to iTunes? If not, has apple devised a way to down mix them? Today I downloaded a soundtrack composed of 19 tracks.
Their format is FLAC (24bit depth and 96kHz sampling).

In order to add them to my iTunes library and eventually to my iPod, I converted the files to ALAC (24 bit 48kHz) which is the maximum my 7th gen iPod classic can handle. 

Problem is, iTunes won't let me import those converted files into the library.
I noticed those files have 6 audio channels.
I think that is the problem, and I've started looking for an answer.
Internet wasn't very clear, unfortunately.

My question is : is there a way to import those files to iTunes? 
Is there a way to down mix the files to 2 channel audio or similar, so iTunes can handle them?

(I hope such a conversion wouldn't distort the audio) 
I usually use XLD to convert my audio files, and there's no option for down mixing.
I sorted it out!
You can down mix the audio files from 6channel to 2 channel using ffmpeg
(you have to use the terminal, though).
The down mixing process is quick and there are no perceivable distortions in the audio.