George Whiteside made a pretty fantastic (d)iskette (O)rgan which he posted on YouTube as Phantom of the Floppera [Download source code]. He discusses some of the frequency properties of floppies.
between the 5¼" and 3½" drives, the 3½" drives produced the most audible low frequencies, and the 5¼" drives produced the cleanest and highest notes. I hypothesized that the older drives were more over-engineered than their modern descendents, allowing them to operate farther out of spec, i.e. play higher notes. The newer drives are flimsier by comparison, and literally rattled better at low frequencies.