The image above is an interior photo of the Atlanta Auditorium Armory circa early twentieth century. Atlanta began hosting the Old Time Fiddler's Convention here in 1913 and drew in visitors from across the state and around the region. These gatherings have been described as a "veritable montage of humanity as ladies in silks and expensive furs mixed with workin' folk in plain attire, as city folk and country folk rubbed elbows, quarrelled over the merits of rival favorites and patted their feet as one man to the strans of the music they had come to hear" (Atlanta Journal 1914) One of my references, Pickin' on Peachtree, by Wayne Daniel, has excellent quotes from convention enthusiasts from back in the day describing the scene.
Here's one of my favorites from the Atlanta Constitution in 1926:
"Practically three thousand persons filled to overflowing the lower part of the building, and created an atmosphere that was something like the enthusiasm of a prize fight, added to the getting happy of an old time camp meeting. Members of the audience got the spirit and moved out into the aisles, for a double shuffle...they fiddled solos, in duets, in deafening ensembles. The fiddled in the regular way, on their knees, backward and foward, and blindfolded. Since the burning of Rome, there has never been such fiddling."
The Municipal Auditorium held some big name concerts early on in the 1970s but was eventually acquired by Georgia State University. Finally in the early 80s, demolition of the auditorium began to make way for a student parking deck.
For more info: Wayne Daniel on the old city auditorium