This thoughtpath is more of a braindump for future project-ideas rather'n directly-relevant to floppyBird... But, even floppyBird isn't particularly-relevant to floppyBird, since this project-page is kinda a two-parter, with multiple tangents, anyhow.

A tiny bit of background:
The idea, again, is to record audio [samples] directly onto a floppy-disk. As I've imagined, the entire [simple] system, record and playback, would require little more than a PC floppy-drive and some simple circuitry, no microcontroller.
Playback from a single track/cylinder I've got down to a simple T-Flip-Flop, a transistor, and a speaker.
Recording, though, is a bit more complicated, due to the controller built in to a floppy drive. This controller has some protection logic to prevent accidental overwrites, e.g. if you try to record on a track for longer than a single rotation. Thus, timing of a few write-related signals is highly important. I'd thought it was only feasible with a microcontroller, but I recently had an idea.
If the controller used for writing was unaware of the 'index' pulse, and maybe some other signals, it would have no reason to go into what Imma call 'protection', and, thus, timing isn't critical.
One thought: Use a separate controller board, from a second floppy drive, which is *not* connected to the index sensor, nor the spindle motor. At that point, the controller might as well think the disk's track is *huge*, or even linear (like a tape). Thus, recording could be performed without regard to timing.
Index-pulsing is still useful, however, since a simple way to record/playback from *multiple* tracks, sequentially, is to tie the index output to the step input, making it auto-advance with each rotation, kinda like a CD or record (LP, 45, etc.).
Thus, using *two* controller-boards for recording: one handles the waveforms written to the disk, the other handles stepping through tracks and rotation.

As an aside, this may also benefit my microstepping idea from a while back. (Probably discussed in my KayPro Floppy Recovery project).
Microstepping the read/write head may be possible with precise timing to the Step/Direction inputs. The Problem, however, is that each change to Step causes the floppy controller to wait for the head to settle into position on the new track before reading/writing is allowed. So, microstepping *between* tracks would cause the controller to continuously *block* reading/writing. So, keep the read/write controller separate from the step/rotation controller, and it might just be possible.

(Microstepping between tracks is an idea I had for attempting to recover data from old disks which may have warped over time, causing oblong or off-center circular tracks. This effect is more common on 5.25in floppies whose circular spindle-hole may've been stretched by many insertions over the years.
But, microstepping in this case, for audio recording/playback, might be quite handy, as well. This'd allow a spiralling track, rather than dozens of concentric tracks. Thus, playback/recording would be uninterrupted with each rotation.
And, yes, I'm very aware that *without* microstepping, any audio recorded/played-back will be at the very least distorted with each track-advance. Thus, an idea, presently, to use each track as a repeating audio sample, 1/5th of a second in duration... selectable via MIDI)