Besides the guitar sounding different, it just seems that spring '76 soundboard sound somewhat 'distant' and the spring '77 soundboards are more in your face.
I may be in the minority, however, I like the spring '76 sound. Lots of the recordings are just beautiful. 7/18/76 is a classic show.
Speaking of spring '76, there were lots of radio shows (Philly, NY, Boston, Chicago, SF, if not more). Do you think there was a purpose to these radio shows (ie: to show the country they were back after retirement)?