I have to admit that I've been referring to this cartoon as The Symphony Hour, but its official title is just Symphony Hour. My mistake.
This is another Riley Thompson cartoon where he has cast the animators by character. Mickey is mostly done by Les Clark and Marvin Woodward, with a bit of Ken Muse and a sprinkling of Bernie Wolf. Les Clark gets the confident, in-control Mickey at the start of the cartoon. The animation is slick as a whistle and beautifully drawn. For all of that, Marvin Woodward actually gets the more interesting Mickey scenes. Instead of being in control, Woodward's scenes have Mickey react to everything going wrong. As great as Clark's animation is, I'm betting that Woodward had more fun.
Ed Love does Pete in a somewhat old-fashioned way. By this I mean that by the time of this cartoon, there was a streamlining of characer design going on. In the mid-thirties, the Disney characters have lots of wrinkles in their clothing and all kinds of follow-through in their fleshy bodies. By this time, a lot of that was pared away, but Love's Pete still has that fleshiness.
I wonder the final shot is a satirical jab at Walt Disney himself. Pete ends up hiding Mickey behind him while he takes the bows for Mickey's work. Is Pete a stand-in for Disney and the hidden Mickey a comment on the artists who didn't get screen credit at this point in time?
Bernie Wolf does a very interesting Donald. He catches Donald's temperament without resorting to the kinds of fireworks that Dick Lundy used when Donald's temper exploded. His Donald is also thick with multiple images and dry brush streaks to sell the idea of fast action. Wolf draws a great, mean Mickey when he's holding that gun.
With the exception of a couple of Muse shots of Mickey, the rest of the animators just do 'bits.' There's not a lot of acting here for Horace, Clarabelle, Clara or Goofy. They're all slickly animated, but they're just there to put across gags. Only Horace reacts to what's going on with other characters in scene 61 by Jack Campbell. Clarabelle, Clara and Goofy exist in a kind of limbo, playing their instruments in a vacuum.
In many ways, this is a 'high concept' cartoon. It's based on a funny idea that's well executed; the gags themselves are nothing special. The fun comes from Riley Thompson giving the animators lots of room to work, and in the case of Clark, Woodward, Love and Wolf, it pays off.