There was sound (storms, rover, walking etc) but I uploaded music over (wipes off all sound)... it can be quiet on mars!
radio chat sounds great as background noise etc, would enhance the ambience.... BTW have you ever considered pre-recorded radio commands/acknowlegments? ie,, key 1 = 'roger', key 2='On My way',
key 3= 'need assitance' etc.. Sounding like nasa radio chat..
??