27 mm-wide paper roll

That’s a small roll of paper.

Because it is easy and cheap. You can buy inkjet cartridges which include the printhead. These are the hardest parts.

Now you „only“ need a motion system.

For a laser printer you need much more complex parts.

I guess if this project takes off they will start looking into Laser printers.

They do have lossless audio now, like since a few weeks.

Anyway, normal speakers don’t go above or below human audible frequencies.