I agree! But that's exactly my point: 1 type of machine is ok, another isn't, so it is not just a matter of all machines make derivative work. To draw the line

I agree! But that's exactly my point: 1 type of machine is ok, another isn't, so it is not just a matter of all machines make derivative work. To draw the line more carefully is an open question. I would be surprised if a machine that "uses information sent into it in a substantive way" is a perfect deliminator. OTTOMH musicians might present some compelling objections.