2 Jukeboxes cannot play the same song in the same world at the same time. However, it does work with 2 different songs and mixes them together. Within render distance, when I play the same song in 2 jukeboxes, the one that has been playing the longest stops and makes note particles. When I moved a jukebox far enough outside render distance of the second jukebox and play the same song, it works like normal. However, when I return to the jukebox that hasn't moved, it doesn't play the song and doesn't make note particles. I have not tested this with all the discs, I only tested this with Pigstep, Wait, and Chirp.